/* ==========================================================================
   TEER Education Platform — Style System v3
   Design: Deep blue (#1e3a5f) + white, professional medical aesthetic.
   Multi-page visual experience — each section distinct.
   ========================================================================== */

/* --- CSS Variables --- */
:root {
  --primary: #1e3a5f;
  --primary-dark: #101f33;
  --primary-medium: #152942;
  --primary-light: #2c5282;
  --secondary: #2b6cb0;
  --accent: #4299e1;
  --accent-light: #63b3ed;
  --accent-pale: #bee3f8;
  --blue-50: #ebf8ff;
  --blue-100: #bee3f8;
  --blue-700: #2b6cb0;
  --blue-800: #2a4365;
  --light-bg: #f5f8fb;
  --ultralight-bg: #fafcfd;
  --white: #ffffff;
  --text: #1a202c;
  --text-secondary: #4a5568;
  --text-muted: #718096;
  --text-light: #a0aec0;
  --success: #38a169;
  --success-bg: #f0fff4;
  --success-border: #c6f6d5;
  --warning: #d69e2e;
  --warning-bg: #fffff0;
  --danger: #e53e3e;
  --danger-bg: #fff5f5;
  --border: #e2e8f0;
  --border-light: #edf2f7;
  --shadow-sm: 0 1px 3px rgba(0,0,0,0.06), 0 1px 2px rgba(0,0,0,0.04);
  --shadow: 0 4px 14px rgba(0,0,0,0.08), 0 2px 6px rgba(0,0,0,0.04);
  --shadow-md: 0 8px 24px rgba(0,0,0,0.10), 0 4px 8px rgba(0,0,0,0.05);
  --shadow-lg: 0 16px 48px rgba(0,0,0,0.12), 0 6px 12px rgba(0,0,0,0.06);
  --shadow-xl: 0 24px 64px rgba(0,0,0,0.14), 0 8px 16px rgba(0,0,0,0.08);
  --radius-sm: 0.375rem;
  --radius: 0.5rem;
  --radius-lg: 0.75rem;
  --radius-xl: 1rem;
  --radius-2xl: 1.25rem;
  --header-height: 68px;
  --content-max: 1200px;
  --transition: 0.2s ease;
}

/* --- Reset & Base --- */
*,*::before,*::after{margin:0;padding:0;box-sizing:border-box;}
html{scroll-behavior:smooth;font-size:16px;-webkit-text-size-adjust:100%;scroll-padding-top:calc(var(--header-height) + 16px);}
body{
  font-family:-apple-system,BlinkMacSystemFont,"Segoe UI",Roboto,"Helvetica Neue",Arial,"PingFang SC","Hiragino Sans GB","Microsoft YaHei",sans-serif;
  color:var(--text);line-height:1.7;background:var(--white);
  -webkit-font-smoothing:antialiased;-moz-osx-font-smoothing:grayscale;overflow-x:hidden;
}

/* --- Accessibility --- */
.sr-only{position:absolute;width:1px;height:1px;padding:0;margin:-1px;overflow:hidden;clip:rect(0,0,0,0);white-space:nowrap;border-width:0;}
.skip-link{position:absolute;top:-40px;left:0;background:var(--primary);color:var(--white);padding:8px 16px;z-index:200;border-radius:0 0 var(--radius-sm) 0;font-size:.875rem;text-decoration:none;}
.skip-link:focus{top:0;}
*:focus-visible{outline:2px solid var(--accent);outline-offset:2px;}

/* --- Typography --- */
h1,h2,h3,h4,h5,h6{line-height:1.3;font-weight:700;color:var(--primary);}
h1{font-size:clamp(2rem,5vw,3rem);letter-spacing:-0.02em;}
h2{font-size:clamp(1.5rem,4vw,2.25rem);}
h3{font-size:1.25rem;}
h4{font-size:1.125rem;}
p{margin-bottom:1rem;}
a{color:var(--secondary);text-decoration:underline;text-underline-offset:2px;transition:color var(--transition);}
a:hover{color:var(--primary-dark);}
strong{font-weight:700;}

/* ==========================================================================
   HEADER & STICKY NAVIGATION
   ========================================================================== */
header{
  background:linear-gradient(180deg,var(--primary-dark) 0%,var(--primary) 100%);
  position:sticky;top:0;z-index:1000;height:var(--header-height);
  box-shadow:0 2px 16px rgba(0,0,0,0.18);
}
nav{max-width:var(--content-max);margin:0 auto;padding:0 1.5rem;display:flex;justify-content:space-between;align-items:center;height:100%;}

.logo{
  color:var(--white);font-size:1.2rem;font-weight:700;text-decoration:none;
  display:flex;align-items:center;gap:0.5rem;white-space:nowrap;letter-spacing:-0.01em;
}
.logo svg{flex-shrink:0;}

.nav-toggle{
  display:flex;align-items:center;background:none;border:none;color:var(--white);
  font-size:1.5rem;cursor:pointer;padding:0.5rem;border-radius:var(--radius-sm);
  line-height:1;transition:background var(--transition);
}
.nav-toggle:hover{background:rgba(255,255,255,0.1);}

/* Nav menu */
.nav-menu{
  position:fixed;top:var(--header-height);left:0;right:0;bottom:0;
  background:var(--primary-dark);flex-direction:column;padding:1rem;gap:0;
  transform:translateX(100%);transition:transform 0.3s ease-in-out;
  list-style:none;display:flex;z-index:99;overflow-y:auto;
}
.nav-menu.open{transform:translateX(0);}

.nav-menu>li{position:relative;}

.nav-menu>li>a,
.nav-menu>li>.nav-toggle-label{
  color:var(--white);text-decoration:none;padding:.875rem 1rem;
  display:flex;align-items:center;justify-content:space-between;
  border-radius:var(--radius);transition:background 0.15s;
  font-weight:500;font-size:.95rem;cursor:pointer;gap:0.5rem;
}
.nav-menu>li>a:hover,
.nav-menu>li>.nav-toggle-label:hover{background:rgba(255,255,255,0.08);}

.nav-arrow{display:inline-block;font-size:.65rem;transition:transform 0.2s;opacity:0.6;}
.nav-dropdown.open>.nav-toggle-label .nav-arrow{transform:rotate(180deg);}

.nav-dropdown-menu{
  list-style:none;background:rgba(0,0,0,0.2);border-radius:var(--radius);
  padding:.375rem 0;margin:.25rem 0 0 .5rem;display:none;
  border-left:2px solid rgba(255,255,255,0.15);
}
.nav-dropdown.open .nav-dropdown-menu{display:block;}
.nav-dropdown-menu a{
  color:rgba(255,255,255,0.85)!important;padding:.625rem 1rem!important;
  font-size:.875rem!important;display:block!important;border-radius:0!important;text-decoration:none!important;
}
.nav-dropdown-menu a:hover{background:rgba(255,255,255,0.06)!important;color:var(--white)!important;}

.nav-menu a[data-nav].nav-active{background:rgba(66,153,225,0.15);color:var(--accent-light);font-weight:600;}

@media (min-width:1024px){
  .nav-toggle{display:none;}
  .nav-menu{
    position:static;transform:none;flex-direction:row;background:transparent;
    padding:0;gap:.125rem;box-shadow:none;overflow-y:visible;bottom:auto;
  }
  .nav-menu>li>a,
  .nav-menu>li>.nav-toggle-label{padding:.5rem .875rem;font-size:.875rem;border-radius:var(--radius-sm);}
  .nav-dropdown-menu{
    position:absolute;top:100%;left:0;min-width:200px;
    background:var(--primary-dark);border-radius:0 0 var(--radius) var(--radius);
    box-shadow:0 8px 32px rgba(0,0,0,0.25);padding:.5rem 0;margin:.25rem 0 0 0;
    border-left:none;border-top:2px solid var(--accent);
  }
  .nav-dropdown-menu a{padding:.625rem 1.25rem!important;white-space:nowrap;}
  .nav-menu a[data-nav].nav-active{border-radius:var(--radius-sm);}
}

/* ==========================================================================
   HERO SECTION
   ========================================================================== */
.hero{
  background:linear-gradient(135deg,var(--primary-dark) 0%,var(--primary) 30%,var(--primary-light) 60%,var(--secondary) 100%);
  color:var(--white);padding:5rem 1.5rem 6rem;position:relative;overflow:hidden;
  min-height:85vh;display:flex;align-items:center;
}
.hero::before{
  content:'';position:absolute;top:-30%;right:-15%;width:700px;height:700px;
  background:radial-gradient(circle,rgba(66,153,225,0.12) 0%,transparent 70%);pointer-events:none;
}
.hero::after{
  content:'';position:absolute;bottom:-20%;left:-10%;width:500px;height:500px;
  background:radial-gradient(circle,rgba(66,153,225,0.08) 0%,transparent 70%);pointer-events:none;
}

.hero-content{max-width:900px;margin:0 auto;position:relative;z-index:1;text-align:center;}

.hero h1{color:var(--white);line-height:1.15;margin-bottom:1.25rem;font-size:clamp(2.25rem,6vw,3.5rem);}
.hero .subtitle{
  font-size:clamp(1rem,2vw,1.3rem);color:rgba(255,255,255,0.8);
  margin-bottom:2.5rem;max-width:650px;margin-left:auto;margin-right:auto;line-height:1.6;
}

/* Hero Search */
.hero-search{
  max-width:560px;margin:0 auto 3.5rem;display:flex;gap:0;
  border-radius:var(--radius-xl);overflow:hidden;
  box-shadow:0 8px 32px rgba(0,0,0,0.2);
}
.hero-search input{
  flex:1;padding:1rem 1.5rem;border:none;font-size:1rem;outline:none;color:var(--text);background:var(--white);
}
.hero-search input::placeholder{color:var(--text-muted);}
.hero-search button{
  padding:1rem 1.75rem;border:none;background:var(--accent);color:var(--white);
  font-weight:600;font-size:.95rem;cursor:pointer;transition:background var(--transition);white-space:nowrap;
}
.hero-search button:hover{background:var(--secondary);}

/* Hero Stats */
.hero-stats{display:grid;grid-template-columns:repeat(3,1fr);gap:1.5rem;max-width:700px;margin:0 auto;}
.stat-card{
  background:rgba(255,255,255,0.08);backdrop-filter:blur(8px);
  border-radius:var(--radius-xl);padding:1.5rem 1rem;text-align:center;
  border:1px solid rgba(255,255,255,0.12);transition:transform var(--transition),background var(--transition);
}
.stat-card:hover{transform:translateY(-4px);background:rgba(255,255,255,0.12);}
.stat-number{font-size:2rem;font-weight:800;color:var(--accent-light);line-height:1;margin-bottom:.5rem;letter-spacing:-0.02em;}
.stat-label{font-size:.85rem;color:rgba(255,255,255,0.75);line-height:1.3;font-weight:500;}

@media (max-width:639px){
  .hero-stats{grid-template-columns:1fr;gap:1rem;}
  .hero{padding:3.5rem 1rem 4rem;min-height:auto;}
}

/* ==========================================================================
   SECTION LAYOUTS
   ========================================================================== */
.page-section{padding:6rem 0;position:relative;}
.page-section:nth-child(even){background:var(--light-bg);}

.section-header{text-align:center;margin-bottom:3.5rem;}
.section-header h2{margin-bottom:.75rem;position:relative;display:inline-block;}
.section-header h2::after{
  content:'';display:block;width:48px;height:3px;background:var(--accent);
  margin:.75rem auto 0;border-radius:2px;
}
.section-header p{color:var(--text-secondary);font-size:1.1rem;max-width:600px;margin:0 auto;}

.container{max-width:var(--content-max);margin:0 auto;padding:0 1.5rem;}

/* ==========================================================================
   ABOUT SECTION — asymmetric split + visual
   ========================================================================== */
.about-layout{display:grid;grid-template-columns:1fr;gap:3rem;align-items:center;}
@media (min-width:768px){.about-layout{grid-template-columns:1.2fr 0.8fr;}}

.about-text h3{font-size:1.5rem;margin-bottom:1rem;color:var(--primary);}
.about-text p{margin-bottom:1rem;color:var(--text-secondary);line-height:1.8;}

.about-visual{
  background:linear-gradient(145deg,var(--primary) 0%,var(--primary-light) 60%,var(--secondary) 100%);
  border-radius:var(--radius-2xl);padding:3rem 2rem;color:var(--white);text-align:center;
  position:relative;overflow:hidden;box-shadow:var(--shadow-lg);min-height:360px;
  display:flex;flex-direction:column;align-items:center;justify-content:center;
}
.about-visual::before{
  content:'';position:absolute;top:-40%;right:-30%;width:300px;height:300px;
  background:radial-gradient(circle,rgba(255,255,255,0.1) 0%,transparent 70%);pointer-events:none;
}
.about-visual p{font-size:.95rem;opacity:0.85;line-height:1.7;}

/* ==========================================================================
   INDICATIONS — criteria cards with checkmarks
   ========================================================================== */
.indications-grid{display:grid;grid-template-columns:1fr;gap:1.5rem;}
@media (min-width:640px){.indications-grid{grid-template-columns:repeat(2,1fr);}}

.indication-card{
  background:var(--white);border-radius:var(--radius-xl);padding:2rem 1.75rem;
  box-shadow:var(--shadow-sm);border:1px solid var(--border);position:relative;
  transition:transform var(--transition),box-shadow var(--transition);
}
.indication-card:hover{transform:translateY(-3px);box-shadow:var(--shadow);}

.check-badge{
  width:44px;height:44px;border-radius:50%;
  background:linear-gradient(135deg,var(--success) 0%,#48bb78 100%);
  display:flex;align-items:center;justify-content:center;margin-bottom:1.25rem;
  box-shadow:0 4px 12px rgba(56,161,105,0.25);
}
.check-badge svg{width:20px;height:20px;stroke:var(--white);}

.indication-card h4{color:var(--primary);margin-bottom:.75rem;font-size:1.1rem;}
.indication-card p{color:var(--text-secondary);font-size:.92rem;margin-bottom:1rem;line-height:1.7;}

.indication-tag{
  display:inline-block;padding:.3rem .9rem;background:var(--blue-50);color:var(--blue-700);
  border-radius:9999px;font-size:.78rem;font-weight:600;letter-spacing:.01em;
}
.indication-tag.emerging{background:#faf5ff;color:#6b46c1;}

/* ==========================================================================
   PROCEDURE — numbered timeline
   ========================================================================== */
.procedure-timeline{max-width:860px;margin:0 auto;}
.step-row{display:flex;gap:2rem;position:relative;padding-bottom:3rem;}
.step-row:last-child{padding-bottom:0;}
.step-marker{flex-shrink:0;position:relative;display:flex;flex-direction:column;align-items:center;}
.step-number{
  width:52px;height:52px;border-radius:50%;
  background:linear-gradient(135deg,var(--primary) 0%,var(--primary-light) 100%);
  color:var(--white);display:flex;align-items:center;justify-content:center;
  font-weight:700;font-size:1.25rem;z-index:1;flex-shrink:0;
  box-shadow:0 0 0 8px var(--white),0 4px 16px rgba(30,58,95,0.2);
}
.step-line{width:2px;flex:1;background:var(--border);margin-top:.5rem;min-height:40px;}
.step-row:last-child .step-line{display:none;}

.step-content{
  background:var(--white);border-radius:var(--radius-xl);padding:1.75rem 2rem;
  box-shadow:var(--shadow-sm);border:1px solid var(--border);flex:1;
  transition:box-shadow var(--transition);
}
.step-content:hover{box-shadow:var(--shadow);}
.step-content h4{color:var(--primary);margin-bottom:.5rem;font-size:1.1rem;}
.step-content p{color:var(--text-secondary);font-size:.92rem;margin-bottom:0;line-height:1.7;}

@media (max-width:639px){
  .step-row{gap:1rem;}
  .step-number{width:40px;height:40px;font-size:1rem;box-shadow:0 0 0 5px var(--white),0 4px 12px rgba(30,58,95,0.2);}
  .step-content{padding:1.25rem 1rem;}
}

/* ==========================================================================
   DEVICES — comparison cards with badges
   ========================================================================== */
.devices-grid{display:grid;grid-template-columns:1fr;gap:1.75rem;}
@media (min-width:768px){.devices-grid{grid-template-columns:repeat(3,1fr);}}

.device-card{
  background:var(--white);border-radius:var(--radius-2xl);overflow:hidden;
  box-shadow:var(--shadow-sm);border:1px solid var(--border);
  transition:transform var(--transition),box-shadow var(--transition);display:flex;flex-direction:column;
}
.device-card:hover{transform:translateY(-4px);box-shadow:var(--shadow-lg);}

.device-card-header{
  background:linear-gradient(135deg,var(--primary) 0%,var(--primary-light) 100%);
  color:var(--white);padding:1.75rem 1.5rem;text-align:center;position:relative;overflow:hidden;
}
.device-card-header::before{
  content:'';position:absolute;top:-50%;right:-50%;width:150px;height:150px;
  background:radial-gradient(circle,rgba(255,255,255,0.1) 0%,transparent 70%);pointer-events:none;
}
.device-card-header h3{color:var(--white);font-size:1.3rem;margin-bottom:.25rem;}
.device-badge{
  display:inline-block;padding:.25rem .75rem;background:rgba(255,255,255,0.15);
  border-radius:9999px;font-size:.72rem;font-weight:600;letter-spacing:.04em;text-transform:uppercase;margin-top:.5rem;
}

.device-card-body{padding:1.75rem 1.5rem;flex:1;display:flex;flex-direction:column;}
.device-card-body p{color:var(--text-secondary);font-size:.92rem;line-height:1.7;margin-bottom:1.25rem;}

.device-meta{display:flex;flex-direction:column;gap:.6rem;margin-top:auto;padding-top:1.25rem;border-top:1px solid var(--border-light);}
.device-meta-item{display:flex;align-items:center;gap:.5rem;font-size:.85rem;color:var(--text-secondary);}
.device-meta-item strong{color:var(--primary);font-size:.72rem;text-transform:uppercase;letter-spacing:.06em;min-width:90px;}

/* ==========================================================================
   EVIDENCE — data table
   ========================================================================== */
.evidence-table-wrap{
  overflow-x:auto;border-radius:var(--radius-xl);
  box-shadow:var(--shadow-md);border:1px solid var(--border);
  -webkit-overflow-scrolling:touch;margin-bottom:1.5rem;background:var(--white);
}
.evidence-table{width:100%;border-collapse:collapse;font-size:.9rem;min-width:900px;}
.evidence-table thead th{
  background:linear-gradient(180deg,var(--primary-light) 0%,var(--primary) 100%);
  color:var(--white);text-align:left;padding:1rem 1.25rem;font-weight:600;
  white-space:nowrap;font-size:.82rem;letter-spacing:.03em;text-transform:uppercase;
  border-bottom:2px solid var(--secondary);
}
.evidence-table tbody td{padding:1rem 1.25rem;border-bottom:1px solid var(--border-light);vertical-align:top;line-height:1.5;}
.evidence-table tbody tr:last-child td{border-bottom:none;}
.evidence-table tbody tr{transition:background var(--transition);}
.evidence-table tbody tr:hover td{background:var(--blue-50);}
.evidence-table tbody tr:nth-child(even) td{background:var(--ultralight-bg);}
.evidence-table tbody tr:nth-child(even):hover td{background:var(--blue-50);}
.evidence-note{text-align:center;color:var(--text-muted);font-size:.9rem;max-width:700px;margin:0 auto;line-height:1.6;}

/* ==========================================================================
   TRAINING — 3-column learning path
   ========================================================================== */
.training-grid{display:grid;grid-template-columns:1fr;gap:2rem;}
@media (min-width:768px){.training-grid{grid-template-columns:repeat(3,1fr);}}

.training-card{
  background:var(--white);border-radius:var(--radius-2xl);overflow:hidden;
  box-shadow:var(--shadow-sm);border:1px solid var(--border);display:flex;
  flex-direction:column;transition:transform var(--transition),box-shadow var(--transition);
}
.training-card:hover{transform:translateY(-3px);box-shadow:var(--shadow);}

.training-card-header{
  background:linear-gradient(135deg,var(--primary) 0%,var(--secondary) 100%);
  color:var(--white);padding:2.5rem 1.5rem 1.5rem;text-align:center;position:relative;overflow:hidden;
}
.path-number{
  width:48px;height:48px;border-radius:50%;background:rgba(255,255,255,0.15);
  display:flex;align-items:center;justify-content:center;margin:0 auto 1rem;
  font-size:1.25rem;font-weight:700;border:2px solid rgba(255,255,255,0.3);
}
.training-card-header h3{color:var(--white);font-size:1.15rem;}
.training-card-header p{color:rgba(255,255,255,0.75);font-size:.85rem;margin-bottom:0;margin-top:.25rem;}

.training-card-body{padding:1.75rem 1.5rem;flex:1;display:flex;flex-direction:column;}
.training-card-body p{color:var(--text-secondary);font-size:.92rem;line-height:1.7;margin-bottom:1.5rem;}
.training-card-body .btn{margin-top:auto;align-self:flex-start;}

/* ==========================================================================
   QUIZ — interactive card-based
   ========================================================================== */
.quiz-progress{
  text-align:center;margin-bottom:2rem;font-weight:600;color:var(--secondary);
  font-size:.95rem;background:var(--white);display:inline-block;padding:.5rem 1.5rem;
  border-radius:9999px;box-shadow:var(--shadow-sm);border:1px solid var(--border);
}

.quiz-card{
  background:var(--white);border-radius:var(--radius-xl);padding:2rem;
  margin-bottom:1.25rem;box-shadow:var(--shadow-sm);border:1px solid var(--border);
  transition:box-shadow var(--transition);
}
.quiz-card:hover{box-shadow:var(--shadow);}

.quiz-question{font-weight:700;color:var(--primary);margin-bottom:1.25rem;font-size:1.05rem;line-height:1.5;}

.quiz-options{list-style:none;}
.quiz-options li{margin-bottom:.5rem;}
.quiz-options button{
  width:100%;text-align:left;padding:.85rem 1.25rem;border:1.5px solid var(--border);
  background:var(--white);border-radius:var(--radius);cursor:pointer;
  transition:all var(--transition);font-size:.95rem;color:var(--text);line-height:1.5;
}
.quiz-options button:hover:not(:disabled){background:var(--light-bg);border-color:var(--accent);transform:translateX(4px);}
.quiz-options button:focus{outline:2px solid var(--accent);outline-offset:2px;}
.quiz-options button.correct{background-color:var(--success-bg);border-color:var(--success);color:#22543d;font-weight:600;}
.quiz-options button.incorrect{background-color:var(--danger-bg);border-color:var(--danger);color:#742a2a;}
.quiz-options button:disabled{cursor:default;opacity:0.9;}

.quiz-feedback{
  margin-top:.75rem;padding:.85rem 1.25rem;border-radius:var(--radius);
  font-size:.9rem;display:none;line-height:1.6;
}
.quiz-feedback.show{display:block;}
.quiz-feedback.correct{background-color:var(--success-bg);color:#22543d;border-left:4px solid var(--success);}
.quiz-feedback.incorrect{background-color:var(--danger-bg);color:#742a2a;border-left:4px solid var(--danger);}

/* ==========================================================================
   VIDEOS — masonry grid with category tabs
   ========================================================================== */
.video-tabs{display:flex;justify-content:center;gap:.5rem;margin-bottom:2.5rem;flex-wrap:wrap;}
.video-tab{
  padding:.6rem 1.5rem;border:2px solid var(--border);background:var(--white);
  border-radius:9999px;cursor:pointer;font-weight:600;font-size:.875rem;
  color:var(--text-secondary);transition:all var(--transition);
}
.video-tab:hover,.video-tab.active{border-color:var(--accent);color:var(--primary);background:var(--blue-50);}

.video-grid{display:grid;grid-template-columns:1fr;gap:1.5rem;}
@media (min-width:640px){.video-grid{grid-template-columns:repeat(2,1fr);}}

.video-card{
  background:var(--white);border-radius:var(--radius-xl);overflow:hidden;
  box-shadow:var(--shadow-sm);border:1px solid var(--border);
  transition:transform var(--transition),box-shadow var(--transition);
}
.video-card:hover{transform:translateY(-2px);box-shadow:var(--shadow-md);}

.video-player-wrap{position:relative;background:#000;aspect-ratio:16/9;overflow:hidden;}
.video-placeholder{
  width:100%;height:100%;background:linear-gradient(135deg,var(--primary) 0%,#0a1a2e 100%);
  display:flex;flex-direction:column;align-items:center;justify-content:center;
  color:var(--white);text-align:center;padding:1.5rem;
}
.video-placeholder p:first-child{font-weight:700;font-size:1rem;margin-bottom:.25rem;}
.video-placeholder p:last-child{font-size:.8rem;opacity:.75;margin-bottom:0;}

.play-overlay{
  position:absolute;top:50%;left:50%;transform:translate(-50%,-50%);width:64px;height:64px;
  background:rgba(255,255,255,0.92);border-radius:50%;display:flex;align-items:center;
  justify-content:center;cursor:pointer;transition:transform var(--transition),background var(--transition);
  box-shadow:var(--shadow-lg);border:none;
}
.play-overlay:hover{transform:translate(-50%,-50%) scale(1.1);background:var(--white);}
.play-overlay svg{width:24px;height:24px;fill:var(--primary);margin-left:3px;}

.video-controls{
  display:flex;align-items:center;gap:.75rem;padding:.625rem 1rem;
  background:#1a202c;color:var(--white);
}
.video-controls button{background:none;border:none;color:var(--white);cursor:pointer;padding:.25rem;display:flex;align-items:center;}
.progress-bar{flex:1;height:6px;background:#4a5568;border-radius:3px;cursor:pointer;overflow:hidden;}
.progress-fill{height:100%;background:var(--accent);width:0%;border-radius:3px;transition:width .1s linear;}
.time-display{font-size:.75rem;font-variant-numeric:tabular-nums;min-width:80px;text-align:right;}

.video-info{padding:1rem 1.25rem;}
.video-info h4{font-size:1rem;margin-bottom:.25rem;}
.video-info p{font-size:.875rem;color:var(--text-secondary);margin-bottom:0;}

/* ==========================================================================
   BUTTONS
   ========================================================================== */
.btn{
  display:inline-flex;align-items:center;justify-content:center;gap:.5rem;
  padding:.75rem 1.5rem;border-radius:var(--radius);font-weight:600;
  font-size:.95rem;text-decoration:none;transition:all var(--transition);
  border:none;cursor:pointer;line-height:1.4;
}
.btn-primary{background:var(--accent);color:var(--white);}
.btn-primary:hover{background:var(--secondary);transform:translateY(-1px);box-shadow:var(--shadow);}
.btn-secondary{background:transparent;color:var(--white);border:2px solid rgba(255,255,255,0.6);}
.btn-secondary:hover{background:rgba(255,255,255,0.1);border-color:var(--white);}
.btn-outline{background:var(--white);color:var(--primary);border:2px solid var(--border);}
.btn-outline:hover{border-color:var(--accent);color:var(--secondary);}
.btn-sm{padding:.5rem 1rem;font-size:.85rem;}

/* ==========================================================================
   API SECTION
   ========================================================================== */
.api-grid{display:grid;grid-template-columns:1fr;gap:1.25rem;}
@media (min-width:768px){.api-grid{grid-template-columns:repeat(3,1fr);}}
.api-card{
  background:var(--white);padding:1.75rem;border-radius:var(--radius-xl);
  border:1px solid var(--border);box-shadow:var(--shadow-sm);
  transition:transform var(--transition),box-shadow var(--transition);
}
.api-card:hover{transform:translateY(-2px);box-shadow:var(--shadow);}
.api-method-badge{display:inline-block;padding:.15rem .55rem;border-radius:4px;font-size:.72rem;font-weight:700;letter-spacing:.03em;margin-right:.5rem;}
.api-method-get{background:var(--success-bg);color:#22543d;}
.api-method-post{background:var(--warning-bg);color:#744210;}
.api-card h4{font-size:.95rem;margin-bottom:.5rem;}
.api-card p{color:var(--text-secondary);font-size:.875rem;margin-bottom:0;}

/* ==========================================================================
   BACK TO TOP
   ========================================================================== */
.back-to-top{
  position:fixed;bottom:24px;right:24px;width:48px;height:48px;
  border-radius:50%;background:var(--primary);color:var(--white);border:none;
  cursor:pointer;font-size:1.25rem;box-shadow:var(--shadow-lg);
  display:flex;align-items:center;justify-content:center;z-index:150;
  opacity:0;visibility:hidden;
  transition:opacity .3s,visibility .3s,transform .3s;
}
.back-to-top.visible{opacity:1;visibility:visible;}
.back-to-top:hover{background:var(--primary-light);transform:translateY(-3px);}

/* ==========================================================================
   FOOTER
   ========================================================================== */
footer{
  background:linear-gradient(180deg,var(--primary-dark) 0%,var(--primary) 100%);
  color:var(--white);padding:4rem 1.5rem 1.5rem;
}

.footer-grid{display:grid;grid-template-columns:1fr;gap:2rem;max-width:var(--content-max);margin:0 auto;}
@media (min-width:640px){.footer-grid{grid-template-columns:repeat(2,1fr);}}
@media (min-width:900px){.footer-grid{grid-template-columns:2fr 1fr 1fr;}}

.footer-col h4{
  font-size:1.05rem;margin-bottom:1rem;color:var(--accent);
  letter-spacing:.01em;font-weight:700;
}
.footer-col p,.footer-col a{
  color:#cbd5e0;font-size:.9rem;text-decoration:none;
  line-height:1.9;display:block;transition:color .15s;
}
.footer-col a:hover{color:var(--white);text-decoration:underline;}

.footer-bottom{
  max-width:var(--content-max);margin:3rem auto 0;padding-top:1.5rem;
  border-top:1px solid rgba(255,255,255,0.1);text-align:center;
  font-size:.85rem;color:var(--text-light);
}

/* ==========================================================================
   SCROLL SPY ACTIVE
   ========================================================================== */
.nav-menu a[data-nav].nav-spy-active{
  background:rgba(66,153,225,0.15);
  color:var(--accent-light);
  font-weight:600;
}

/* ==========================================================================
   CHAT WIDGET
   ========================================================================== */
#teer-chat-widget{position:fixed;bottom:20px;right:20px;z-index:9999;font-family:inherit;}

/* ==========================================================================
   UTILITY
   ========================================================================== */
.text-center{text-align:center;}
.mt-2{margin-top:1rem;}
.mt-4{margin-top:2rem;}
.mb-2{margin-bottom:1rem;}
.mb-4{margin-bottom:2rem;}

/* ==========================================================================
   RESPONSIVE
   ========================================================================== */
@media (max-width:767px){
  .page-section{padding:3.5rem 0;}
  .hero-search button{padding:1rem 1.25rem;font-size:.85rem;}
}

/* ==========================================================================
   SCROLLBAR
   ========================================================================== */
::-webkit-scrollbar{width:8px;}
::-webkit-scrollbar-track{background:var(--light-bg);}
::-webkit-scrollbar-thumb{background:var(--text-muted);border-radius:4px;}
::-webkit-scrollbar-thumb:hover{background:var(--text-secondary);}

/* ==========================================================================
   PRINT
   ========================================================================== */
@media print{
  header,footer,.back-to-top,#teer-chat-widget,.nav-toggle{display:none!important;}
  body{font-size:12pt;}
  .page-section{display:block!important;}
  a{color:var(--text);}
}

/* ==========================================================================
   REDUCED MOTION
   ========================================================================== */
@media (prefers-reduced-motion:reduce){
  html{scroll-behavior:auto;}
  *,*::before,*::after{animation-duration:.01ms!important;animation-iteration-count:1!important;transition-duration:.01ms!important;}
}
/* ==========================================================================
   NAVIGATION — sticky + dropdown
   ========================================================================== */
.navbar { position: sticky; top: 0; z-index: 1000; background: var(--primary); box-shadow: var(--shadow); backdrop-filter: blur(10px); }
.nav-container { max-width: var(--content-max); margin: 0 auto; display: flex; align-items: center; padding: 0 24px; height: var(--header-height,64px); }
.logo { display: flex; align-items: center; gap: 8px; color: var(--white); text-decoration: none; font-weight: 700; font-size: 1.25rem; }
.logo-icon { flex-shrink: 0; }
.logo-accent { color: var(--accent-light); font-weight: 400; }
.nav-menu { display: flex; align-items: center; gap: 4px; margin-left: auto; list-style: none; }
.nav-item { position: relative; }
.nav-link, .nav-dropdown-toggle { background: none; border: none; color: rgba(255,255,255,0.85); padding: 8px 14px; border-radius: var(--radius); cursor: pointer; font-size: 0.925rem; font-family: inherit; transition: background 0.2s, color 0.2s; }
.nav-link:hover, .nav-dropdown-toggle:hover { background: rgba(255,255,255,0.1); color: var(--white); }
.dropdown-menu { position: absolute; top: 100%; left: 0; background: var(--white); border-radius: var(--radius); box-shadow: var(--shadow-lg); min-width: 200px; padding: 6px 0; opacity: 0; visibility: hidden; transform: translateY(-4px); transition: all 0.2s; list-style: none; z-index: 1001; }
.nav-item:hover .dropdown-menu, .nav-item:focus-within .dropdown-menu { opacity: 1; visibility: visible; transform: translateY(0); }
.dropdown-link { display: block; padding: 8px 16px; color: var(--text); text-decoration: none; font-size: 0.9rem; transition: background 0.15s; }
.dropdown-link:hover { background: var(--blue-50); color: var(--primary); }
.hamburger-line { display: block; width: 20px; height: 2px; background: var(--white); margin: 4px 0; transition: transform 0.3s, opacity 0.3s; }
.nav-toggle { display: none; background: none; border: none; cursor: pointer; padding: 8px; }

/* mobile nav */
@media (max-width: 768px) {
  .nav-toggle { display: block; }
  .nav-menu { display: none; flex-direction: column; position: absolute; top: var(--header-height,64px); left: 0; right: 0; background: var(--primary-dark); padding: 16px; gap: 8px; }
  .nav-menu.nav-open { display: flex; }
  .nav-item { width: 100%; }
  .dropdown-menu { position: static; background: rgba(255,255,255,0.05); box-shadow: none; opacity: 1; visibility: visible; transform: none; padding-left: 16px; }
  .dropdown-menu a { color: rgba(255,255,255,0.8); }
  .dropdown-menu a:hover { background: rgba(255,255,255,0.1); color: var(--white); }
}

/* ==========================================================================
   HERO
   ========================================================================== */
.hero { background: linear-gradient(135deg, var(--primary) 0%, var(--primary-light) 50%, var(--secondary) 100%); padding: 120px 0 80px; text-align: center; color: var(--white); position: relative; overflow: hidden; }
.hero::before { content:""; position:absolute; inset:0; background: radial-gradient(circle at 30% 50%, rgba(66,153,225,0.15) 0%, transparent 60%); }
.hero-content { position: relative; z-index: 1; }
.hero h1 { font-size: clamp(2rem, 5vw, 3.25rem); font-weight: 800; margin-bottom: 16px; letter-spacing: -0.02em; }
.hero-subtitle { font-size: 1.2rem; color: rgba(255,255,255,0.8); max-width: 700px; margin: 0 auto 32px; line-height: 1.6; }
.hero-stats { display: flex; justify-content: center; gap: 40px; margin-bottom: 32px; }
.hero-stat { display: flex; flex-direction: column; align-items: center; }
.hero-stat-num { font-size: 2.25rem; font-weight: 800; }
.hero-stat-label { font-size: 0.85rem; color: rgba(255,255,255,0.7); margin-top: 4px; }
.hero-cta { display: flex; gap: 12px; justify-content: center; }
.btn { display: inline-block; padding: 12px 28px; border-radius: var(--radius); font-weight: 600; text-decoration: none; transition: all 0.2s; cursor: pointer; font-size: 0.95rem; border: 2px solid transparent; }
.btn-primary { background: var(--accent); color: var(--white); border-color: var(--accent); }
.btn-primary:hover { background: var(--secondary); border-color: var(--secondary); transform: translateY(-1px); box-shadow: var(--shadow-lg); }
.btn-outline { background: transparent; color: var(--white); border-color: rgba(255,255,255,0.4); }
.btn-outline:hover { background: rgba(255,255,255,0.1); border-color: var(--white); }
.btn-sm { padding: 6px 14px; font-size: 0.85rem; }

/* ==========================================================================
   SECTIONS — common
   ========================================================================== */
.section { padding: 80px 0; }
.section-light { background: var(--light-bg); }
.section-dark { background: var(--primary); color: var(--white); }
.section-dark .section-subtitle { color: var(--accent-pale); }
.section-dark h2 { color: var(--white); }
.section-dark .evidence-table { color: var(--text); }
.section-dark .evidence-table thead { background: var(--primary-medium); }
.section-dark .evidence-table thead th { color: var(--white); }
.container { max-width: 1200px; margin: 0 auto; padding: 0 24px; }
.section-header { text-align: center; margin-bottom: 48px; }
.section-header h2 { font-size: 2rem; font-weight: 700; color: var(--primary); margin-bottom: 8px; }
.section-subtitle { color: var(--text-muted); font-size: 1.05rem; max-width: 600px; margin: 0 auto; }

/* ==========================================================================
   ABOUT — 3 column cards
   ========================================================================== */
.about-grid { display: grid; grid-template-columns: repeat(auto-fit, minmax(320px, 1fr)); gap: 24px; }
.about-card { background: var(--white); border-radius: var(--radius-lg); padding: 32px; box-shadow: var(--shadow-sm); transition: transform 0.2s, box-shadow 0.2s; }
.about-card:hover { transform: translateY(-2px); box-shadow: var(--shadow-lg); }
.about-card-icon { width: 56px; height: 56px; background: var(--blue-50); border-radius: 12px; display: flex; align-items: center; justify-content: center; margin-bottom: 16px; color: var(--primary); }
.about-card h3 { font-size: 1.15rem; color: var(--primary); margin-bottom: 8px; }
.about-card p { color: var(--text-secondary); line-height: 1.6; }

/* ==========================================================================
   INDICATIONS — 4 card grid with tags
   ========================================================================== */
.indications-grid { display: grid; grid-template-columns: repeat(auto-fit, minmax(500px, 1fr)); gap: 20px; }
@media (max-width: 768px) { .indications-grid { grid-template-columns: 1fr; } }
.indication-card { background: var(--white); border-radius: var(--radius-lg); padding: 28px; box-shadow: var(--shadow-sm); border-left: 4px solid var(--primary); transition: box-shadow 0.2s; }
.indication-card:hover { box-shadow: var(--shadow); }
.indication-card-accent { display: flex; gap: 16px; margin-bottom: 12px; }
.indication-icon { flex-shrink: 0; width: 44px; height: 44px; background: var(--blue-50); border-radius: 10px; display: flex; align-items: center; justify-content: center; color: var(--primary); }
.indication-card h3 { font-size: 1.1rem; color: var(--primary); margin-bottom: 6px; }
.indication-card p { color: var(--text-secondary); line-height: 1.5; margin-bottom: 8px; }
.indication-tag { display: inline-block; padding: 3px 10px; border-radius: 20px; font-size: 0.75rem; font-weight: 600; }
.tag-recommended { background: var(--success-bg); color: var(--success); }
.tag-emerging { background: var(--warning-bg); color: var(--warning); }
.tag-team { background: var(--blue-50); color: var(--primary); }
.indication-criteria { margin-top: 12px; padding-left: 18px; }
.indication-criteria li { color: var(--text-secondary); font-size: 0.9rem; padding: 3px 0; }
.indication-criteria li::marker { color: var(--accent); }

/* ==========================================================================
   PROCEDURE — timeline
   ========================================================================== */
.procedure-timeline { max-width: 800px; margin: 0 auto; position: relative; padding-left: 60px; }
.procedure-timeline::before { content:""; position:absolute; left: 26px; top: 0; bottom: 0; width: 2px; background: linear-gradient(to bottom, var(--accent), var(--primary-light)); }
.procedure-step { display: flex; gap: 24px; margin-bottom: 36px; position: relative; }
.procedure-step:last-child { margin-bottom: 0; }
.step-number { width: 52px; height: 52px; background: var(--primary); color: var(--white); border-radius: 50%; display: flex; align-items: center; justify-content: center; font-weight: 700; font-size: 1.2rem; position: absolute; left: -60px; z-index: 1; box-shadow: 0 0 0 4px var(--light-bg); }
.step-content { background: var(--white); border-radius: var(--radius); padding: 20px 24px; box-shadow: var(--shadow-sm); flex: 1; transition: box-shadow 0.2s; }
.step-content:hover { box-shadow: var(--shadow); }
.step-content h3 { font-size: 1.1rem; color: var(--primary); margin-bottom: 6px; }
.step-content p { color: var(--text-secondary); line-height: 1.6; }

/* ==========================================================================
   DEVICES — 5 card grid with badges
   ========================================================================== */
.devices-grid { display: grid; grid-template-columns: repeat(auto-fit, minmax(240px, 1fr)); gap: 20px; }
.device-card { background: var(--white); border-radius: var(--radius-lg); overflow: hidden; box-shadow: var(--shadow-sm); transition: transform 0.2s, box-shadow 0.2s; }
.device-card:hover { transform: translateY(-4px); box-shadow: var(--shadow-xl); }
.device-badge { padding: 8px 14px; font-size: 0.75rem; font-weight: 700; text-transform: uppercase; letter-spacing: 0.05em; }
.badge-primary { background: var(--primary); color: var(--white); }
.badge-accent { background: var(--accent); color: var(--white); }
.badge-secondary { background: var(--secondary); color: var(--white); }
.badge-innovative { background: var(--blue-50); color: var(--primary); }
.device-card h3 { padding: 0 20px; margin-top: 16px; font-size: 1.2rem; color: var(--primary); }
.device-mfr { padding: 0 20px; color: var(--text-muted); font-size: 0.85rem; margin-bottom: 8px; }
.device-card p { padding: 0 20px 16px; color: var(--text-secondary); line-height: 1.5; font-size: 0.9rem; }
.device-features { list-style: none; padding: 0 20px 20px; }
.device-features li { padding: 6px 0; border-bottom: 1px solid var(--border-light); font-size: 0.88rem; color: var(--text-secondary); }
.device-features li:last-child { border-bottom: none; }
.device-features li::before { content:"\2713"; color: var(--success); margin-right: 8px; font-weight: 700; }

/* ==========================================================================
   EVIDENCE — data table
   ========================================================================== */
.table-responsive { overflow-x: auto; border-radius: var(--radius-lg); box-shadow: var(--shadow-sm); }
.evidence-table { width: 100%; border-collapse: collapse; background: var(--white); font-size: 0.9rem; }
.evidence-table thead { background: var(--primary); }
.evidence-table th { padding: 14px 16px; text-align: left; color: var(--white); font-weight: 600; font-size: 0.85rem; }
.evidence-table td { padding: 12px 16px; border-bottom: 1px solid var(--border-light); color: var(--text-secondary); }
.evidence-table tbody tr:nth-child(even) { background: var(--ultralight-bg); }
.evidence-table tbody tr:hover { background: var(--blue-50); }
.evidence-table td:first-child { font-weight: 600; color: var(--primary); }
.evidence-table td:last-child { font-family: monospace; font-size: 0.8rem; color: var(--text-muted); }

/* ==========================================================================
   TRAINING — 3 tier cards
   ========================================================================== */
.training-grid { display: grid; grid-template-columns: repeat(auto-fit, minmax(300px, 1fr)); gap: 24px; }
.training-card { background: var(--white); border-radius: var(--radius-lg); padding: 32px; box-shadow: var(--shadow-sm); border-top: 4px solid var(--border); transition: transform 0.2s, box-shadow 0.2s; }
.training-card:hover { transform: translateY(-2px); box-shadow: var(--shadow); }
.training-card-featured { border-top-color: var(--accent); box-shadow: var(--shadow-lg); transform: scale(1.03); }
.training-card-featured:hover { transform: scale(1.03) translateY(-2px); }
.training-tier { font-size: 0.75rem; font-weight: 700; text-transform: uppercase; letter-spacing: 0.08em; color: var(--text-muted); margin-bottom: 12px; }
.training-card h3 { font-size: 1.25rem; color: var(--primary); margin-bottom: 16px; }
.training-card ul { list-style: none; padding: 0; margin-bottom: 24px; }
.training-card li { padding: 8px 0; border-bottom: 1px solid var(--border-light); font-size: 0.92rem; color: var(--text-secondary); }
.training-card li:last-child { border-bottom: none; }
.training-card li::before { content:"\2713"; color: var(--success); margin-right: 8px; }
.training-cta { text-align: center; padding-top: 16px; border-top: 1px solid var(--border-light); }
.training-cta span { font-weight: 600; color: var(--primary); }

/* ==========================================================================
   FOOTER
   ========================================================================== */
footer { background: var(--primary-dark); color: rgba(255,255,255,0.7); padding: 48px 0 0; }
.footer-grid { display: grid; grid-template-columns: 2fr 1fr 1fr; gap: 40px; max-width: 1200px; margin: 0 auto; padding: 0 24px; }
@media (max-width: 768px) { .footer-grid { grid-template-columns: 1fr; } }
footer h4 { color: var(--white); font-size: 1rem; margin-bottom: 12px; }
footer p { font-size: 0.9rem; line-height: 1.6; margin-bottom: 8px; }
footer ul { list-style: none; padding: 0; }
footer li { padding: 4px 0; }
footer a { color: rgba(255,255,255,0.6); text-decoration: none; font-size: 0.9rem; transition: color 0.2s; }
footer a:hover { color: var(--accent-light); }
.footer-bottom { max-width: 1200px; margin: 32px auto 0; padding: 20px 24px; border-top: 1px solid rgba(255,255,255,0.1); text-align: center; font-size: 0.8rem; color: rgba(255,255,255,0.4); }

/* ==========================================================================
   BACK TO TOP
   ========================================================================== */
.back-to-top { position: fixed; bottom: 24px; right: 24px; width: 44px; height: 44px; background: var(--primary); color: var(--white); border: none; border-radius: 50%; font-size: 1.5rem; cursor: pointer; opacity: 0; visibility: hidden; transition: all 0.3s; z-index: 999; box-shadow: var(--shadow); }
.back-to-top.visible { opacity: 1; visibility: visible; }
.back-to-top:hover { background: var(--accent); transform: translateY(-2px); }

/* ==========================================================================
   ACCESSIBILITY
   ========================================================================== */
.skip-link { position: absolute; top: -100px; left: 8px; background: var(--primary); color: var(--white); padding: 8px 16px; z-index: 1002; border-radius: 0 0 var(--radius) var(--radius); transition: top 0.2s; }
.skip-link:focus { top: 0; }

/* ==========================================================================
   SCROLL ANIMATION
   ========================================================================== */
@keyframes fadeInUp { from { opacity: 0; transform: translateY(24px); } to { opacity: 1; transform: translateY(0); } }
.about-card, .indication-card, .procedure-step, .device-card, .training-card { animation: fadeInUp 0.5s ease-out both; }
.about-card:nth-child(2) { animation-delay: 0.1s; }
.about-card:nth-child(3) { animation-delay: 0.2s; }
@media (prefers-reduced-motion: reduce) { .about-card, .indication-card, .procedure-step, .device-card, .training-card { animation: none; } }

/* ==========================================================================
   QUIZ SECTION
   ========================================================================== */
.quiz-container { max-width: 700px; margin: 0 auto; }
.quiz-progress-bar { height: 6px; background: var(--border-light); border-radius: 3px; margin-bottom: 24px; position: relative; }
.quiz-progress-fill { height: 100%; background: var(--accent); border-radius: 3px; transition: width 0.3s; }
.quiz-card { background: var(--white); border-radius: var(--radius-lg); padding: 32px; box-shadow: var(--shadow-sm); margin-bottom: 20px; }
.quiz-card h3 { color: var(--primary); font-size: 1.1rem; margin-bottom: 16px; }
.quiz-option { display: block; padding: 14px 20px; margin: 8px 0; border: 2px solid var(--border); border-radius: var(--radius); cursor: pointer; transition: all 0.2s; font-size: 0.95rem; }
.quiz-option:hover { border-color: var(--accent); background: var(--blue-50); }
.quiz-option.selected { border-color: var(--accent); background: var(--blue-50); font-weight: 600; }
.quiz-option.correct { border-color: var(--success); background: var(--success-bg); }
.quiz-option.wrong { border-color: var(--danger); background: var(--danger-bg); }
.quiz-result { text-align: center; padding: 20px; background: var(--white); border-radius: var(--radius-lg); box-shadow: var(--shadow-sm); margin-top: 20px; }
.quiz-result .score { font-size: 2.5rem; font-weight: 800; color: var(--primary); }
.quiz-score-text { font-size: 1rem; color: var(--text-muted); margin-top: 8px; }
.quiz-explanation { background: var(--ultralight-bg); border-radius: var(--radius); padding: 16px; margin-top: 12px; font-size: 0.9rem; color: var(--text-secondary); }

/* ==========================================================================
   VIDEO SECTION
   ========================================================================== */
.video-tabs { display: flex; gap: 8px; justify-content: center; margin-bottom: 32px; flex-wrap: wrap; }
.video-tab { padding: 10px 22px; border: 2px solid var(--border); border-radius: 30px; background: var(--white); cursor: pointer; font-size: 0.9rem; font-weight: 600; color: var(--text-secondary); transition: all 0.2s; }
.video-tab:hover { border-color: var(--accent); color: var(--primary); }
.video-tab.active { background: var(--primary); color: var(--white); border-color: var(--primary); }
.video-grid { display: grid; grid-template-columns: repeat(auto-fit, minmax(280px, 1fr)); gap: 20px; }
.video-card { background: var(--white); border-radius: var(--radius-lg); overflow: hidden; box-shadow: var(--shadow-sm); transition: transform 0.2s, box-shadow 0.2s; }
.video-card:hover { transform: translateY(-2px); box-shadow: var(--shadow); }
.video-thumb { height: 160px; background: linear-gradient(135deg, var(--primary), var(--secondary)); display: flex; align-items: center; justify-content: center; color: var(--white); font-size: 0.9rem; font-weight: 600; }
.video-card h4 { padding: 16px 16px 4px; font-size: 1rem; color: var(--primary); }
.video-card p { padding: 0 16px 16px; font-size: 0.85rem; color: var(--text-muted); }

/* ==========================================================================
   FAQ SECTION
   ========================================================================== */
.faq-list { max-width: 800px; margin: 0 auto; }
.faq-item { background: var(--white); border-radius: var(--radius); margin-bottom: 12px; box-shadow: var(--shadow-sm); overflow: hidden; }
.faq-question { padding: 20px 24px; cursor: pointer; font-weight: 600; color: var(--primary); display: flex; justify-content: space-between; align-items: center; transition: background 0.2s; }
.faq-question:hover { background: var(--blue-50); }
.faq-question::after { content: '+'; font-size: 1.3rem; color: var(--text-muted); }
.faq-item.open .faq-question::after { content: '−'; }
.faq-answer { padding: 0 24px 20px; font-size: 0.95rem; color: var(--text-secondary); line-height: 1.7; display: none; }
.faq-item.open .faq-answer { display: block; }

/* ==========================================================================
   API DOCS
   ========================================================================== */
.api-endpoints { display: grid; grid-template-columns: repeat(auto-fit, minmax(300px, 1fr)); gap: 20px; }
.api-card { background: var(--white); border-radius: var(--radius-lg); padding: 24px; box-shadow: var(--shadow-sm); }
.api-card h4 { font-size: 0.95rem; margin-bottom: 8px; color: var(--primary); }
.api-card pre { background: var(--primary-dark); color: var(--accent-light); padding: 12px 16px; border-radius: var(--radius); font-size: 0.82rem; overflow-x: auto; margin-top: 8px; }
.method-post { background: var(--success); color: var(--white); padding: 2px 8px; border-radius: 4px; font-size: 0.75rem; margin-right: 6px; }
.method-get { background: var(--accent); color: var(--white); padding: 2px 8px; border-radius: 4px; font-size: 0.75rem; margin-right: 6px; }