/* ============================================================
   CarbonTier — Premium Platform Design System
   Palette: white canvas, deep navy for authority, emerald for
   climate/growth signal, soft glass panels for depth without
   noise. Typography pairs a rounded-geometric display face
   (Sora) with a neutral workhorse body face (Inter) and a
   monospace utility face (IBM Plex Mono) for data/stats —
   the credibility cue borrowed from scientific dashboards.
   ============================================================ */

:root{
  --white:      #FFFFFF;
  --canvas:     #F7F9F9;
  --navy:       #0A1C33;
  --navy-2:     #102A4C;
  --emerald:    #0E9F6E;
  --emerald-lt: #34D399;
  --ink:        #0B1220;
  --muted:      #5B6472;
  --line:       rgba(10,28,51,0.08);
  --glass-bg:   rgba(255,255,255,0.55);
  --glass-brd:  rgba(255,255,255,0.6);
  --glass-navy: rgba(10,28,51,0.55);

  --display: 'Sora', sans-serif;
  --body:    'Inter', sans-serif;
  --mono:    'IBM Plex Mono', monospace;

  --radius: 18px;
  --shadow: 0 20px 60px -20px rgba(10,28,51,0.18);
}

[data-theme="dark"]{
  --white:  #0A1220;
  --canvas: #0D1626;
  --ink:    #F2F5F4;
  --muted:  #9AA6AC;
  --line:   rgba(255,255,255,0.10);
  --glass-bg: rgba(16,26,42,0.55);
  --glass-brd: rgba(255,255,255,0.08);
}

*{ box-sizing:border-box; margin:0; padding:0; }
html{ scroll-behavior:smooth; }
body{
  background:var(--canvas); color:var(--ink);
  font-family:var(--body); line-height:1.6; font-size:16px;
  -webkit-font-smoothing:antialiased; transition:background .3s ease, color .3s ease;
}
a{ color:inherit; text-decoration:none; }
img{ max-width:100%; display:block; }
ul{ list-style:none; }
.wrap{ max-width:1200px; margin:0 auto; padding:0 32px; }

h1,h2,h3,.display{ font-family:var(--display); font-weight:700; letter-spacing:-0.02em; line-height:1.1; }
h1{ font-size:clamp(2.6rem, 5.4vw, 4.6rem); }
h2{ font-size:clamp(1.8rem, 3.2vw, 2.6rem); }
h3{ font-size:1.15rem; }
.eyebrow{
  font-family:var(--mono); font-size:0.76rem; letter-spacing:0.14em; text-transform:uppercase;
  color:var(--emerald); display:inline-flex; align-items:center; gap:8px; margin-bottom:16px;
}
.eyebrow::before{ content:''; width:6px; height:6px; border-radius:50%; background:var(--emerald); }
.lede{ font-size:1.15rem; color:var(--muted); max-width:58ch; }
.center{ text-align:center; margin-left:auto; margin-right:auto; }

/* ---------- Buttons ---------- */
.btn{ display:inline-flex; align-items:center; gap:8px; padding:14px 28px; border-radius:999px;
  font-weight:600; font-size:0.95rem; border:1px solid transparent; cursor:pointer;
  transition:transform .2s ease, box-shadow .2s ease, background .2s ease; }
.btn:hover{ transform:translateY(-2px); }
.btn-primary{ background:var(--navy); color:#fff; box-shadow:0 12px 30px -10px rgba(10,28,51,0.5); }
.btn-primary:hover{ background:var(--emerald); box-shadow:0 12px 30px -10px rgba(14,159,110,0.5); }
.btn-ghost{ background:var(--glass-bg); backdrop-filter:blur(12px); border-color:var(--line); color:var(--ink); }
.btn-sm{ padding:9px 18px; font-size:0.85rem; }

/* ---------- Header ---------- */
header{ position:sticky; top:0; z-index:100; background:rgba(247,249,249,0.75);
  backdrop-filter:blur(14px); border-bottom:1px solid var(--line); }
[data-theme="dark"] header{ background:rgba(13,22,38,0.75); }
nav{ display:flex; align-items:center; justify-content:space-between; padding:16px 32px; max-width:1200px; margin:0 auto; }
.logo{ font-family:var(--display); font-weight:700; font-size:1.2rem; display:flex; align-items:center; gap:10px; }
.logo .mark{ width:26px; height:26px; border-radius:8px; background:linear-gradient(135deg, var(--emerald), var(--navy)); }
.navlinks{ display:flex; align-items:center; gap:30px; }
.navlinks a{ font-size:0.92rem; font-weight:500; color:var(--muted); transition:color .15s ease; }
.navlinks a:hover, .navlinks a.active{ color:var(--ink); }
.nav-actions{ display:flex; align-items:center; gap:14px; }
.theme-toggle{ width:38px; height:38px; border-radius:50%; border:1px solid var(--line);
  background:var(--glass-bg); display:flex; align-items:center; justify-content:center; cursor:pointer; }

/* ---------- Hero ---------- */
.hero{ padding:110px 0 90px; position:relative; overflow:hidden; }
.hero-grid{ display:grid; grid-template-columns:1.05fr 0.95fr; gap:50px; align-items:center; }
.hero-ctas{ display:flex; gap:14px; margin-top:32px; flex-wrap:wrap; }
.hero p.lede{ margin-top:20px; }

/* globe / node visualization */
.globe-wrap{ position:relative; aspect-ratio:1/1; }
.globe-svg{ width:100%; height:100%; }
.globe-ring{ fill:none; stroke:var(--line); stroke-width:1; }
.globe-node{ fill:var(--emerald); animation:pulse 3s ease-in-out infinite; }
.globe-node.navy{ fill:var(--navy-2); }
.globe-link{ fill:none; stroke:var(--emerald); stroke-width:1; opacity:0.35; stroke-dasharray:4 4; animation:dash 20s linear infinite; }
@keyframes pulse{ 0%,100%{ opacity:0.5; transform:scale(1); } 50%{ opacity:1; transform:scale(1.4); } }
@keyframes dash{ to{ stroke-dashoffset:-200; } }

/* ---------- Glass cards ---------- */
.glass{ background:var(--glass-bg); backdrop-filter:blur(16px); border:1px solid var(--glass-brd);
  border-radius:var(--radius); box-shadow:var(--shadow); }
.card{ padding:32px; display:flex; flex-direction:column; gap:14px; transition:transform .25s ease, box-shadow .25s ease; }
.card:hover{ transform:translateY(-6px); }
.card .icon{ width:46px; height:46px; border-radius:12px; display:flex; align-items:center; justify-content:center;
  background:linear-gradient(135deg, rgba(14,159,110,0.15), rgba(10,28,51,0.08)); color:var(--emerald); }
.card p{ color:var(--muted); font-size:0.94rem; }
.grid-2{ display:grid; grid-template-columns:repeat(2,1fr); gap:24px; }
.grid-3{ display:grid; grid-template-columns:repeat(3,1fr); gap:24px; }
.grid-4{ display:grid; grid-template-columns:repeat(4,1fr); gap:20px; }

/* ---------- Sections ---------- */
section{ padding:100px 0; }
.section-navy{ background:linear-gradient(180deg, var(--navy), var(--navy-2)); color:#fff; }
.section-navy .muted-nv{ color:rgba(255,255,255,0.65); }
.section-navy .lede{ color:rgba(255,255,255,0.7); }
.reveal{ opacity:0; transform:translateY(24px); transition:opacity .7s ease, transform .7s ease; }
.reveal.in{ opacity:1; transform:translateY(0); }

/* ---------- Challenge cards ---------- */
.chal-card{ position:relative; padding:28px; border-radius:16px; border:1px solid var(--line);
  background:var(--white); overflow:hidden; cursor:pointer; transition:transform .25s ease, box-shadow .25s ease; }
.chal-card:hover{ transform:translateY(-4px); box-shadow:var(--shadow); }
.chal-card .num{ font-family:var(--mono); font-size:0.75rem; color:var(--muted); }
.chal-card h3{ margin-top:10px; }

/* ---------- Project cards (Innovation Hub) ---------- */
.proj-card{ padding:26px; border-radius:16px; }
.trl-bar{ height:6px; border-radius:4px; background:var(--line); overflow:hidden; margin-top:8px; }
.trl-fill{ height:100%; background:linear-gradient(90deg, var(--emerald-lt), var(--emerald)); }
.proj-meta{ display:flex; justify-content:space-between; font-family:var(--mono); font-size:0.72rem; color:var(--muted); margin-top:14px; }
.avatars{ display:flex; margin-top:14px; }
.avatars span{ width:28px; height:28px; border-radius:50%; background:var(--navy-2); border:2px solid var(--white);
  margin-left:-8px; display:flex; align-items:center; justify-content:center; font-size:0.65rem; color:#fff; font-family:var(--mono); }
.avatars span:first-child{ margin-left:0; }

/* ---------- AI Assistant ---------- */
.ai-panel{ padding:40px; display:flex; flex-direction:column; gap:20px; }
.ai-row{ display:flex; gap:16px; align-items:flex-start; }
.ai-dot{ width:34px; height:34px; border-radius:10px; background:linear-gradient(135deg, var(--emerald), var(--navy)); flex-shrink:0; }
.ai-row .txt{ font-size:0.92rem; color:var(--muted); }

/* ---------- Stats ---------- */
.stat{ text-align:center; }
.stat .num{ font-family:var(--mono); font-size:2.4rem; font-weight:700; }
.stat .label{ font-size:0.85rem; color:var(--muted); margin-top:6px; }
.section-navy .stat .label{ color:rgba(255,255,255,0.65); }

/* ---------- Challenge feature ---------- */
.challenge-feature{ display:grid; grid-template-columns:1.2fr 0.8fr; gap:0; border-radius:20px; overflow:hidden; }
.challenge-feature .cf-left{ padding:44px; background:linear-gradient(135deg, var(--navy), var(--navy-2)); color:#fff; }
.challenge-feature .cf-right{ padding:44px; background:var(--white); }
.deadline-pill{ display:inline-block; padding:6px 14px; border-radius:999px; background:rgba(255,255,255,0.12);
  font-family:var(--mono); font-size:0.75rem; margin-bottom:16px; }
.prize-row{ display:flex; justify-content:space-between; padding:12px 0; border-bottom:1px dashed var(--line); font-size:0.9rem; }
.prize-row:last-child{ border-bottom:none; }

/* ---------- Success stories ---------- */
.story-card{ display:grid; grid-template-columns:auto 1fr; gap:20px; align-items:center; padding:26px; }
.story-badge{ font-family:var(--mono); font-size:0.7rem; padding:6px 12px; border-radius:999px; background:rgba(14,159,110,0.12); color:var(--emerald); width:fit-content; }

/* ---------- Partners ---------- */
.logo-row{ display:flex; flex-wrap:wrap; gap:36px; align-items:center; justify-content:center; opacity:0.6; }
.logo-chip{ font-family:var(--display); font-weight:700; font-size:1.1rem; color:var(--muted); }

/* ---------- CTA ---------- */
.cta-final{ text-align:center; border-radius:28px; padding:80px 40px; background:linear-gradient(135deg, var(--navy), #0E9F6E22), var(--navy); position:relative; overflow:hidden; }
.cta-final h2{ color:#fff; max-width:20ch; margin:0 auto; }
.cta-final p{ color:rgba(255,255,255,0.7); margin:18px auto 0; }
.cta-btns{ display:flex; gap:14px; justify-content:center; margin-top:32px; flex-wrap:wrap; }

/* ---------- Footer ---------- */
footer{ background:var(--navy); color:rgba(255,255,255,0.7); padding:64px 0 30px; }
.footer-grid{ display:grid; grid-template-columns:2fr 1fr 1fr 1fr; gap:40px; }
footer h4{ color:#fff; font-size:0.88rem; margin-bottom:14px; }
footer a{ display:block; margin-bottom:8px; font-size:0.9rem; color:rgba(255,255,255,0.65); }
footer a:hover{ color:var(--emerald-lt); }
.footer-bottom{ margin-top:48px; padding-top:24px; border-top:1px solid rgba(255,255,255,0.12); display:flex; justify-content:space-between; font-size:0.8rem; flex-wrap:wrap; gap:10px; }

/* ---------- Responsive ---------- */
@media (max-width: 900px){
  .hero-grid, .grid-2, .grid-3, .grid-4, .footer-grid, .challenge-feature, .story-card{ grid-template-columns:1fr; }
  .navlinks{ display:none; }
  section{ padding:64px 0; }
}

/* ---------- Accessibility ---------- */
a:focus-visible, button:focus-visible, input:focus-visible{ outline:2px solid var(--emerald); outline-offset:2px; }
@media (prefers-reduced-motion: reduce){
  html{ scroll-behavior:auto; }
  .reveal{ opacity:1; transform:none; transition:none; }
  .globe-node, .globe-link{ animation:none; }
  .btn:hover{ transform:none; }
}