/* ==========================================================================
   VibeCode 101 — Single Source of Truth Theme
   Used by EVERY page (index, lessons, slides, ep01, cheatsheet)
   
   Design DNA:
   - 4-pastel palette (pink + lavender + mint + peach) — NOT hot pink
   - Fraunces serif display + Inter sans + IBM Plex Sans Thai
   - Dark plum ink (#3D2C4F) + cream bg (#FFFBF7)
   - Soft organic blobs, gradient hero
   - Border-radius scale: 8/14/20/28/pill
   
   THIS IS THE ONLY FILE TO EDIT FOR GLOBAL DESIGN CHANGES.
   ========================================================================== */

/* ========================== TOKENS ========================== */
:root{
  /* 4-pastel palette */
  --pink-50:#FFF1F6;     --pink-100:#FFE0EC;    --pink-200:#FFC8DC;    --pink-300:#FFA8C4;    --pink-400:#FF89AC;
  --lavender-50:#F5F1FF; --lavender-100:#E8DEFF;--lavender-200:#D4C5FF;--lavender-300:#BBA6FF;--lavender-400:#9F87F0;
  --mint-50:#EFFBF6;     --mint-100:#D6F5E5;    --mint-200:#B5EBCD;    --mint-300:#8DDBB0;    --mint-400:#65C895;
  --peach-50:#FFF5EE;    --peach-100:#FFE6D4;   --peach-200:#FFD0AE;   --peach-300:#FFB888;   --peach-400:#FF9F66;

  /* Brand colors */
  --primary:  var(--pink-300);
  --secondary:var(--lavender-300);
  --accent:   var(--mint-300);
  --warm:     var(--peach-300);

  /* Surface */
  --bg:       #FFFBF7;     /* cream */
  --bg-2:     var(--pink-50);
  --bg-3:     var(--lavender-50);
  --paper:    #ffffff;
  --paper-2:  #fafafa;

  /* Text */
  --ink:      #3D2C4F;     /* dark plum */
  --ink-2:    #5a4670;
  --ink-3:    #7d6c92;
  --muted:    #6B5B7B;

  /* Borders */
  --line:     #f0e8ee;
  --line-2:   #e8dde7;

  /* Code */
  --code-bg:  #2d1b3a;
  --code-ink: #fff5f8;

  /* Radius */
  --r-sm:   8px;
  --r-md:   14px;
  --r-lg:   20px;
  --r-xl:   28px;
  --r-pill: 999px;
  --r-blob: 42% 58% 65% 35% / 55% 45% 60% 40%;

  /* Shadows */
  --shadow-sm: 0 2px 8px -2px rgba(61,44,79,0.06);
  --shadow:    0 4px 12px -4px rgba(255,168,196,0.20);
  --shadow-card:0 8px 24px -10px rgba(255,168,196,0.40);
  --shadow-soft:0 10px 40px -12px rgba(187,166,255,0.35);
  --shadow-lg: 0 18px 50px -16px rgba(187,166,255,0.30);
  --shadow-inset: inset 0 1px 0 rgba(255,255,255,0.6);

  /* Spacing */
  --space-1:4px;  --space-2:8px;  --space-3:12px;  --space-4:16px;
  --space-5:20px; --space-6:24px; --space-7:32px;  --space-8:40px;
  --space-9:48px; --space-10:64px;--space-11:80px; --space-12:96px;

  /* Layout */
  --max:   1180px;
  --max-w: 1080px; /* lesson content */

  /* Fonts */
  --font-display:'Fraunces','IBM Plex Sans Thai',Georgia,serif;
  --font-sans:'Inter','IBM Plex Sans Thai',-apple-system,BlinkMacSystemFont,sans-serif;
  --font-mono:'JetBrains Mono','IBM Plex Mono',ui-monospace,monospace;
  --font-thai:'IBM Plex Sans Thai','Inter',sans-serif;

  /* Transitions */
  --t-fast:150ms ease;
  --t:      220ms cubic-bezier(.2,.7,.2,1);
  --t-slow: 400ms ease;

  /* Hero gradient (4 stops) */
  --grad-hero: linear-gradient(135deg, #FFE0EC 0%, #E8DEFF 35%, #D6F5E5 70%, #FFE6D4 100%);
  --grad-text: linear-gradient(120deg, #FF89AC 0%, #9F87F0 50%, #65C895 100%);
}

/* Dark theme overrides */
:root[data-theme="dark"]{
  --bg:       #14101e;
  --bg-2:     #1d1828;
  --bg-3:     #251f33;
  --paper:    #1f1a2c;
  --paper-2:  #261f35;
  --ink:      #f4ecf8;
  --ink-2:    #d4c4e0;
  --ink-3:    #b9a4c9;
  --muted:    #8b7a9d;
  --line:     #362d4a;
  --line-2:   #2d2440;
  --code-bg:  #0d0816;
  --shadow:   0 4px 12px -4px rgba(0,0,0,0.4);
  --shadow-card:0 8px 24px -10px rgba(0,0,0,0.4);
  --grad-hero: linear-gradient(135deg, #2a1a3a 0%, #1f2440 50%, #1a3028 100%);
}

/* ========================== BASE ========================== */
*,*::before,*::after{box-sizing:border-box}
html,body{margin:0;padding:0}
html{scroll-behavior:smooth;scroll-padding-top:80px}
body{
  background:var(--bg);color:var(--ink);
  font-family:var(--font-sans);
  font-size:16px;line-height:1.7;
  -webkit-font-smoothing:antialiased;
  -moz-osx-font-smoothing:grayscale;
  text-rendering:optimizeLegibility;
  overflow-x:hidden;
  transition:background var(--t), color var(--t);
}
body::before{
  content:'';position:fixed;inset:0;pointer-events:none;z-index:0;
  background:
    radial-gradient(ellipse 60% 40% at 15% 0%,rgba(252,231,243,.45),transparent 70%),
    radial-gradient(ellipse 60% 40% at 95% 30%,rgba(232,222,255,.35),transparent 70%);
  transition:background var(--t);
}
[data-theme="dark"] body::before{opacity:0.5}
::selection{background:rgba(255,168,196,0.4);color:var(--ink)}

/* Typography */
h1,h2,h3,h4{
  font-family:var(--font-display);
  font-weight:600;
  letter-spacing:-.022em;
  line-height:1.15;
  margin:0 0 .5em;
  color:var(--ink);
}
h1{font-size:clamp(36px,5vw,56px)}
h2{font-size:clamp(28px,3.5vw,40px)}
h3{font-size:clamp(20px,2.4vw,24px)}
h4{font-size:18px}
p{margin:0 0 1em}
a{color:var(--primary);text-decoration:none;transition:color var(--t-fast)}
a:hover{color:var(--pink-400)}
code{font-family:var(--font-mono);font-size:.92em;background:var(--bg-2);padding:1px 6px;border-radius:6px;color:var(--ink-2)}
pre{font-family:var(--font-mono);background:var(--code-bg);color:var(--code-ink);padding:18px 22px;border-radius:var(--r-md);overflow-x:auto;font-size:13.5px;line-height:1.6;margin:0 0 1em}
pre code{background:transparent;padding:0;color:inherit}

.gradient-text{
  background:var(--grad-text);
  -webkit-background-clip:text;background-clip:text;
  -webkit-text-fill-color:transparent;color:transparent;
}
.eyebrow{
  font:600 11px/1 var(--font-mono);
  letter-spacing:.22em;text-transform:uppercase;
  color:var(--muted);margin-bottom:14px;
  display:inline-block;padding:6px 12px;
  background:var(--bg-2);border-radius:var(--r-pill);
}

/* ========================== TOP NAV ========================== */
.topbar{
  position:sticky;top:0;left:0;right:0;z-index:50;
  display:flex;align-items:center;justify-content:space-between;
  padding:14px 32px;
  backdrop-filter:blur(12px);
  background:rgba(255,251,247,0.78);
  border-bottom:1px solid var(--line);
  transition:box-shadow var(--t), background var(--t);
}
.topbar.scrolled{
  background:rgba(255,251,247,0.95);
  box-shadow:0 4px 24px -8px rgba(187,166,255,0.18);
}
[data-theme="dark"] .topbar{background:rgba(20,16,30,0.78)}
[data-theme="dark"] .topbar.scrolled{background:rgba(20,16,30,0.95)}

.topbar .brand{
  display:inline-flex;align-items:center;gap:10px;
  font:700 15px/1 var(--font-sans);
  color:var(--ink);text-decoration:none;
  letter-spacing:-.01em;
}
.topbar .brand .logo-mark{
  width:36px;height:36px;border-radius:11px;
  background:linear-gradient(135deg,var(--pink-300),var(--lavender-300));
  color:#fff;display:flex;align-items:center;justify-content:center;
  font-size:17px;font-weight:600;
  box-shadow:0 6px 16px -6px rgba(255,168,196,0.5);
}
.topbar .brand .brand-text{display:flex;flex-direction:column;line-height:1.1}
.topbar .brand .brand-text small{
  font:500 10px/1 var(--font-mono);
  color:var(--muted);letter-spacing:.16em;
  text-transform:uppercase;margin-top:3px;
}

.topbar .nav{display:flex;align-items:center;gap:4px;flex-wrap:wrap}
.topbar .nav a{
  display:inline-flex;align-items:center;gap:5px;
  font:500 13.5px/1 var(--font-sans);
  color:var(--ink-3);
  text-decoration:none;padding:8px 14px;border-radius:var(--r-pill);
  transition:color var(--t-fast),background var(--t-fast);
  white-space:nowrap;
}
.topbar .nav a:hover{color:var(--ink);background:var(--bg-2)}
.topbar .nav a.active{color:var(--ink);background:var(--pink-50)}
[data-theme="dark"] .topbar .nav a:hover{background:var(--bg-2)}
[data-theme="dark"] .topbar .nav a.active{background:var(--bg-2);color:var(--pink-300)}

.topbar .actions{display:flex;align-items:center;gap:8px}
.login-cta{
  display:inline-flex;align-items:center;gap:4px;
  padding:8px 16px;border-radius:var(--r-pill);
  font:600 13px/1 var(--font-sans);color:var(--ink);
  background:var(--bg-2);text-decoration:none;
  border:1px solid var(--line);
  transition:all var(--t-fast);
}
.login-cta:hover{background:var(--pink-50);border-color:var(--pink-100);transform:translateY(-1px)}
.theme-toggle{
  appearance:none;background:var(--paper);border:1.5px solid var(--line);
  border-radius:var(--r-pill);width:38px;height:38px;
  display:inline-flex;align-items:center;justify-content:center;
  cursor:pointer;font-size:16px;color:var(--ink-2);
  transition:all var(--t-fast);
}
.theme-toggle:hover{border-color:var(--pink-300);transform:rotate(15deg)}

/* ========================== HERO ========================== */
.hero{
  position:relative;padding:88px 32px 64px;
  text-align:center;overflow:hidden;
  isolation:isolate;
}
.hero::before{
  content:'';position:absolute;inset:0;z-index:-2;
  background:var(--grad-hero);
  opacity:.85;
}
.hero::after{
  content:'';position:absolute;inset:0;z-index:-1;
  background:
    radial-gradient(circle at 20% 20%, rgba(255,168,196,0.45) 0%, transparent 50%),
    radial-gradient(circle at 80% 30%, rgba(187,166,255,0.4) 0%, transparent 50%),
    radial-gradient(circle at 50% 80%, rgba(141,219,176,0.35) 0%, transparent 50%);
}
.hero-inner{position:relative;max-width:780px;margin:0 auto}
.hero-badge{
  display:inline-flex;align-items:center;gap:6px;
  padding:8px 16px;border-radius:var(--r-pill);
  background:rgba(255,255,255,0.85);
  backdrop-filter:blur(8px);
  border:1px solid var(--pink-200);
  font:500 12px/1 var(--font-mono);
  color:var(--ink);letter-spacing:.05em;
  box-shadow:var(--shadow-card);
  margin-bottom:24px;
}
.hero h1{
  font-size:clamp(40px,7vw,80px);
  font-weight:600;line-height:1.05;
  margin:0 0 24px;
}
.hero h1 .gradient-text{
  background:var(--grad-text);
  -webkit-background-clip:text;background-clip:text;
  -webkit-text-fill-color:transparent;color:transparent;
}
.hero .tagline{
  font-size:clamp(15px,1.7vw,18px);
  color:var(--ink-2);max-width:620px;margin:0 auto 36px;line-height:1.7;
}
.hero .cta-row{display:flex;flex-wrap:wrap;gap:12px;justify-content:center}

/* ========================== BUTTONS ========================== */
.btn{
  display:inline-flex;align-items:center;gap:8px;
  padding:13px 24px;border-radius:var(--r-pill);
  font:600 14px/1 var(--font-sans);letter-spacing:-.005em;
  text-decoration:none;cursor:pointer;border:0;
  transition:all var(--t-fast);
}
.btn:active{transform:scale(0.97)}
.btn-primary{
  background:var(--ink);color:var(--bg);
  box-shadow:0 12px 32px -10px rgba(187,166,255,0.4);
}
.btn-primary:hover{
  box-shadow:0 16px 40px -8px rgba(187,166,255,0.55);
  transform:translateY(-2px);color:var(--bg);
}
[data-theme="dark"] .btn-primary{background:var(--pink-300);color:var(--ink)}

.btn-secondary{
  background:rgba(255,255,255,0.85);
  color:var(--ink);border:1.5px solid var(--pink-200);
  backdrop-filter:blur(6px);
}
.btn-secondary:hover{
  border-color:var(--pink-300);
  box-shadow:var(--shadow-card);
  transform:translateY(-2px);color:var(--ink);
}
[data-theme="dark"] .btn-secondary{
  background:var(--paper);border-color:var(--line-2);
}

.btn-ghost{
  background:transparent;color:var(--ink-2);
  border:1.5px solid transparent;
}
.btn-ghost:hover{
  background:var(--bg-2);color:var(--ink);
}

.btn-sm{padding:8px 14px;font-size:13px}

/* ========================== CONTAINER ========================== */
.container{
  max-width:var(--max);margin:0 auto;
  padding:0 32px;
}
@media (max-width:780px){.container{padding:0 20px}}

.section{padding:80px 0}
@media (max-width:780px){.section{padding:60px 0}}

.section-header{
  max-width:620px;margin:0 auto 48px;text-align:center;
}
.section-header.left{text-align:left;margin-left:0}
.section-header h2{margin:0 0 12px}
.section-header p{
  font-size:17px;color:var(--muted);margin:0;line-height:1.7;
}

/* ========================== CARDS ========================== */
.card{
  background:var(--paper);
  border:1px solid var(--line);
  border-radius:var(--r-xl);
  padding:28px;
  box-shadow:var(--shadow-sm);
  transition:transform var(--t), box-shadow var(--t);
}
.card:hover{transform:translateY(-3px);box-shadow:var(--shadow-card)}

.card-pink{     border-color:var(--pink-100);      box-shadow:0 8px 30px -12px rgba(255,168,196,0.45)}
.card-lavender{ border-color:var(--lavender-100);  box-shadow:0 8px 30px -12px rgba(187,166,255,0.45)}
.card-mint{     border-color:var(--mint-100);      box-shadow:0 8px 30px -12px rgba(141,219,176,0.45)}
.card-peach{    border-color:var(--peach-100);     box-shadow:0 8px 30px -12px rgba(255,184,136,0.45)}

.lesson-card{
  display:flex;flex-direction:column;
  background:var(--paper);
  border-radius:var(--r-xl);
  overflow:hidden;
  text-decoration:none;color:inherit;
  border:1px solid var(--line);
  transition:transform var(--t), box-shadow var(--t);
  position:relative;
}
.lesson-card:hover{transform:translateY(-4px);box-shadow:var(--shadow-card)}
.lesson-card.tone-pink{box-shadow:0 8px 30px -12px rgba(255,168,196,0.45)}
.lesson-card.tone-lavender{box-shadow:0 8px 30px -12px rgba(187,166,255,0.45)}
.lesson-card.tone-mint{box-shadow:0 8px 30px -12px rgba(141,219,176,0.45)}
.lesson-card.tone-peach{box-shadow:0 8px 30px -12px rgba(255,184,136,0.45)}
.lesson-card .thumb{
  aspect-ratio:16/9;overflow:hidden;
  background:linear-gradient(135deg,var(--pink-100),var(--lavender-100));
  position:relative;
}
.lesson-card .thumb img{
  width:100%;height:100%;object-fit:cover;display:block;
  transition:transform 500ms cubic-bezier(.2,.7,.2,1);
}
.lesson-card:hover .thumb img{transform:scale(1.05)}
.lesson-card .body{padding:22px 22px 24px;display:flex;flex-direction:column;gap:8px;flex:1}
.lesson-card .num{
  font:600 11px/1 var(--font-mono);
  letter-spacing:.16em;text-transform:uppercase;
  color:var(--muted);
}
.lesson-card h3{
  font:600 19px/1.3 var(--font-display);
  margin:0;color:var(--ink);letter-spacing:-.015em;
}
.lesson-card .desc{
  font-size:14px;color:var(--muted);line-height:1.6;margin:0;
}
.lesson-card .meta{
  margin-top:auto;padding-top:12px;
  display:flex;gap:6px;flex-wrap:wrap;
  font:500 11px/1 var(--font-mono);color:var(--muted);
}
.lesson-card .meta span{
  display:inline-flex;align-items:center;gap:4px;
  padding:4px 9px;border-radius:var(--r-pill);
  background:var(--bg-2);color:var(--ink-3);
}
.lesson-card.tone-pink .meta span{background:var(--pink-50);color:var(--pink-400)}
.lesson-card.tone-lavender .meta span{background:var(--lavender-50);color:var(--lavender-400)}
.lesson-card.tone-mint .meta span{background:var(--mint-50);color:var(--mint-400)}
.lesson-card.tone-peach .meta span{background:var(--peach-50);color:var(--peach-400)}

/* ========================== BADGES ========================== */
.badge{
  display:inline-flex;align-items:center;gap:4px;
  padding:4px 10px;border-radius:var(--r-pill);
  font:600 11px/1.4 var(--font-sans);
  background:var(--bg-2);color:var(--ink-2);
  border:1px solid var(--line);
}
.badge-pink{     background:var(--pink-50);     color:var(--pink-400);     border-color:var(--pink-100)}
.badge-lavender{ background:var(--lavender-50); color:var(--lavender-400); border-color:var(--lavender-100)}
.badge-mint{     background:var(--mint-50);     color:var(--mint-400);     border-color:var(--mint-100)}
.badge-peach{    background:var(--peach-50);    color:var(--peach-400);    border-color:var(--peach-100)}
.badge-dot::before{
  content:'';width:6px;height:6px;border-radius:50%;
  background:currentColor;display:inline-block;
}

/* ========================== STAT CHIPS ========================== */
.stat-chip{
  display:inline-flex;align-items:center;gap:10px;
  padding:12px 20px;border-radius:var(--r-pill);
  background:rgba(255,255,255,0.65);
  backdrop-filter:blur(8px);
  border:1px solid rgba(255,255,255,0.5);
  box-shadow:var(--shadow-sm);
}
.stat-chip .n{
  font:700 18px/1 var(--font-display);
  background:var(--grad-text);
  -webkit-background-clip:text;background-clip:text;
  -webkit-text-fill-color:transparent;color:transparent;
  letter-spacing:-.02em;
}
.stat-chip .l{
  font:500 13px/1 var(--font-sans);color:var(--ink);
}

/* ========================== FOOTER ========================== */
.site-footer{
  margin-top:80px;padding:32px;
  border-top:1px solid var(--line);
  display:flex;justify-content:space-between;flex-wrap:wrap;gap:16px;
  font:500 13px/1.5 var(--font-sans);color:var(--muted);
  max-width:var(--max);margin-left:auto;margin-right:auto;
}
.site-footer a{color:var(--ink-2);text-decoration:none;border-bottom:1px dotted var(--line)}
.site-footer a:hover{color:var(--primary)}
.site-footer .links{display:flex;gap:18px;flex-wrap:wrap}

/* ========================== BLOB FLOATERS ========================== */
.blob{
  position:absolute;border-radius:var(--r-blob);
  filter:blur(60px);opacity:.55;z-index:-1;
  animation:float 7s ease-in-out infinite;
}
.blob.b1{top:-80px;left:-100px;width:300px;height:300px;background:var(--pink-200)}
.blob.b2{top:120px;right:-120px;width:360px;height:360px;background:var(--lavender-200);animation-delay:-2s}
.blob.b3{bottom:80px;left:33%;width:260px;height:260px;background:var(--mint-200);animation-delay:-4s}
@keyframes float{0%,100%{transform:translateY(0) rotate(0)}50%{transform:translateY(-12px) rotate(2deg)}}

/* ========================== DARK MODE TOGGLE ========================== */
.theme-toggle{
  appearance:none;background:var(--paper);border:1.5px solid var(--line);
  border-radius:var(--r-pill);width:38px;height:38px;
  display:inline-flex;align-items:center;justify-content:center;
  cursor:pointer;font-size:16px;color:var(--ink-2);
  transition:all var(--t-fast);
}
.theme-toggle:hover{border-color:var(--pink-300);transform:rotate(15deg)}

/* ========================== FORMS ========================== */
input, textarea{
  font-family:inherit;font-size:14px;color:var(--ink);
  background:var(--paper);border:1.5px solid var(--line);
  border-radius:var(--r-md);padding:10px 14px;
  transition:border-color var(--t-fast);
}
input:focus, textarea:focus{outline:none;border-color:var(--pink-300)}

/* ========================== UTILS ========================== */
.center{text-align:center}
.muted{color:var(--muted)}
.thai{font-family:var(--font-thai)}
.mono{font-family:var(--font-mono)}
.hidden{display:none!important}

/* ========================== TOPBAR DROPDOWN ========================== */
.topbar .nav-group{position:relative;display:inline-block}
.topbar .nav-trigger{
  background:none;border:none;cursor:pointer;
  font-family:inherit;font-size:14px;font-weight:500;
  color:var(--ink);padding:6px 12px;border-radius:100px;
  display:inline-flex;align-items:center;gap:4px;
  transition:all .2s;
}
.topbar .nav-trigger:hover{background:var(--bg-elev);color:var(--pink-500)}
.topbar .nav-trigger .caret{font-size:10px;opacity:0.6;transition:transform .2s}
.topbar .nav-group:hover .nav-trigger .caret{transform:rotate(180deg)}
.topbar .nav-dropdown{
  position:absolute;top:calc(100% + 8px);left:0;
  background:var(--surface);border:1px solid var(--line);
  border-radius:14px;padding:8px;min-width:220px;
  box-shadow:0 12px 28px rgba(0,0,0,.08);
  opacity:0;visibility:hidden;transform:translateY(-8px);
  transition:all .2s;z-index:1000;
}
.topbar .nav-group:hover .nav-dropdown,
.topbar .nav-group:focus-within .nav-dropdown{
  opacity:1;visibility:visible;transform:translateY(0);
}
.topbar .nav-dropdown a{
  display:block;padding:10px 14px;border-radius:8px;
  font-size:13px;font-weight:500;color:var(--ink);
  text-decoration:none;white-space:nowrap;
  transition:all .15s;
}
.topbar .nav-dropdown a:hover{
  background:var(--pink-50);color:var(--pink-500);
  padding-left:18px;
}
.topbar .nav-dropdown a.active{
  background:var(--lavender-50);color:var(--lavender-500);
  font-weight:600;
}

/* ========================== RESPONSIVE ========================== */
@media (max-width:780px){
  .topbar{padding:12px 20px}
  .topbar .nav a{padding:6px 10px;font-size:12.5px}
  .topbar .brand .brand-text small{display:none}
  .hero{padding:64px 20px 48px}
}
.topbar a.nav-live{background:linear-gradient(135deg,#ef4444,#dc2626) !important;color:#fff !important;font-weight:700;padding:8px 14px !important;border-radius:99px;animation:livePulse 2s infinite;text-decoration:none}
.topbar a.nav-live:hover{transform:translateY(-1px);filter:brightness(1.1)}
@keyframes livePulse{0%,100%{box-shadow:0 0 0 0 rgba(239,68,68,.5)}50%{box-shadow:0 0 0 10px rgba(239,68,68,0)}}
.topbar .nav-dropdown a[href*="LiveEp01"]{background:linear-gradient(135deg,#fef2f2,#fff);color:#dc2626;font-weight:700}