:root {
  --coral: #FF8B7E;
  --coral-dark: #E76858;
  --coral-soft: #FFE4DE;
  --butter: #FFD56B;
  --butter-soft: #FFF4E5;
  --mint: #79D4A8;
  --mint-soft: #DDF5E7;
  --sky-soft: #DCEEFF;
  --text: #1F1A18;
  --text-muted: #6B5D58;
  --text-light: #9B8B85;
  --bg: #FFF8F4;
  --bg-alt: #FFEFE7;
  --surface: #FFFFFF;
  --border: #F0D9CF;
  --shadow-sm: 0 2px 8px rgba(231, 104, 88, 0.08);
  --shadow-md: 0 8px 24px rgba(231, 104, 88, 0.12);
  --shadow-lg: 0 20px 60px rgba(231, 104, 88, 0.18);
}

* { box-sizing: border-box; }

html, body {
  margin: 0;
  padding: 0;
  background: var(--bg);
  color: var(--text);
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC",
    "Hiragino Sans GB", "Microsoft YaHei", system-ui, sans-serif;
  font-size: 16px;
  line-height: 1.65;
  -webkit-font-smoothing: antialiased;
}

a { color: var(--coral-dark); text-decoration: none; }
a:hover { text-decoration: underline; }

/* ───── Header ───── */

.site-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 20px 32px;
  background: var(--bg);
}

.site-header .brand {
  font-size: 22px;
  font-weight: 800;
  color: var(--coral-dark);
  letter-spacing: -0.3px;
}

.site-header .brand-emoji {
  margin-right: 6px;
}

.lang-switch-corner {
  display: inline-flex;
  gap: 4px;
  padding: 4px;
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: 999px;
  box-shadow: var(--shadow-sm);
}

.lang-switch-corner a {
  padding: 4px 12px;
  border-radius: 999px;
  font-size: 13px;
  font-weight: 600;
  color: var(--text-muted);
  text-decoration: none;
}

.lang-switch-corner a:hover { text-decoration: none; color: var(--text); }

.lang-switch-corner a.active {
  background: var(--coral);
  color: white;
}

/* ───── Hero ───── */

.hero {
  position: relative;
  padding: 60px 24px 80px;
  text-align: center;
  overflow: hidden;
}

.hero::before {
  content: "";
  position: absolute;
  top: -10%;
  left: 50%;
  transform: translateX(-50%);
  width: 700px;
  height: 700px;
  background: radial-gradient(circle, var(--coral-soft) 0%, transparent 60%);
  z-index: 0;
  pointer-events: none;
}

.hero-inner {
  position: relative;
  max-width: 720px;
  margin: 0 auto;
  z-index: 1;
}

.hero .badge {
  display: inline-block;
  padding: 6px 16px;
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: 999px;
  font-size: 14px;
  font-weight: 600;
  color: var(--coral-dark);
  margin-bottom: 24px;
  box-shadow: var(--shadow-sm);
}

.hero h1 {
  font-size: 56px;
  font-weight: 900;
  letter-spacing: -1.5px;
  line-height: 1.05;
  margin: 0 0 20px;
  background: linear-gradient(135deg, var(--coral) 0%, var(--coral-dark) 100%);
  -webkit-background-clip: text;
  background-clip: text;
  color: transparent;
}

.hero .tagline {
  font-size: 18px;
  color: var(--text-muted);
  margin: 0 0 36px;
  line-height: 1.6;
}

.hero .cta-primary {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 16px 32px;
  background: var(--coral);
  color: white !important;
  border-radius: 999px;
  font-weight: 700;
  font-size: 16px;
  box-shadow: var(--shadow-md);
  cursor: not-allowed;
  opacity: 0.85;
}

.hero .cta-primary:hover { text-decoration: none; }

.hero-sub {
  margin-top: 28px;
  font-size: 14px;
  color: var(--text-muted);
}

/* ───── Section primitives ───── */

.section {
  padding: 80px 24px;
}

.section-alt { background: var(--bg-alt); }

.section-coral {
  background: linear-gradient(135deg, var(--coral) 0%, var(--coral-dark) 100%);
  color: white;
}
.section-coral .section-title { color: white; }
.section-coral .section-sub { color: rgba(255, 255, 255, 0.9); }

.section-inner { max-width: 960px; margin: 0 auto; }

.section-title {
  font-size: 36px;
  font-weight: 800;
  letter-spacing: -0.8px;
  text-align: center;
  margin: 0 0 12px;
}

.section-sub {
  font-size: 16px;
  color: var(--text-muted);
  text-align: center;
  margin: 0 0 48px;
}

/* ───── Use cases grid ───── */

.use-cases {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 20px;
}

.card {
  background: var(--surface);
  border-radius: 20px;
  padding: 28px 24px;
  border: 1px solid var(--border);
  box-shadow: var(--shadow-sm);
  transition: transform 0.18s ease, box-shadow 0.18s ease;
}

.card:hover {
  transform: translateY(-4px);
  box-shadow: var(--shadow-md);
}

.card .emoji {
  font-size: 40px;
  display: block;
  margin-bottom: 12px;
  line-height: 1;
}

.card h3 {
  font-size: 18px;
  font-weight: 700;
  margin: 0 0 6px;
}

.card p {
  font-size: 14px;
  color: var(--text-muted);
  margin: 0;
  line-height: 1.55;
}

/* ───── How it works steps ───── */

.steps {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 24px;
  position: relative;
}

.step {
  background: var(--surface);
  border-radius: 20px;
  padding: 32px 24px;
  text-align: center;
  border: 1px solid var(--border);
  box-shadow: var(--shadow-sm);
}

.step-num {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 44px;
  height: 44px;
  border-radius: 50%;
  background: var(--coral);
  color: white;
  font-size: 20px;
  font-weight: 800;
  margin-bottom: 16px;
}

.step h3 {
  font-size: 17px;
  font-weight: 700;
  margin: 0 0 8px;
}

.step p {
  font-size: 14px;
  color: var(--text-muted);
  margin: 0;
}

/* ───── Trust row ───── */

.trust-row {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 16px;
}

.trust-item {
  text-align: center;
  padding: 24px 16px;
}

.trust-item .emoji {
  font-size: 36px;
  display: block;
  margin-bottom: 10px;
  line-height: 1;
}

.trust-item h3 {
  font-size: 15px;
  font-weight: 700;
  margin: 0 0 4px;
}

.trust-item p {
  font-size: 13px;
  color: var(--text-muted);
  margin: 0;
  line-height: 1.5;
}

/* ───── Schools ───── */

.section-dark {
  background: #1F1A18;
  color: white;
}
.section-dark .section-title { color: white; }
.section-dark .section-sub { color: rgba(255, 255, 255, 0.7); }
.section-dark .other-schools { color: rgba(255, 255, 255, 0.55); }

.schools {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 18px;
  max-width: 880px;
  margin: 0 auto;
}

.school {
  display: flex;
  flex-direction: column;
  justify-content: center;
  align-items: center;
  text-align: center;
  border-radius: 16px;
  padding: 32px 14px;
  min-height: 150px;
  font-weight: 800;
  letter-spacing: -0.3px;
  box-shadow: 0 12px 32px rgba(0, 0, 0, 0.25);
  transition: transform 0.18s ease, box-shadow 0.18s ease;
}

.school:hover {
  transform: translateY(-4px);
  box-shadow: 0 18px 44px rgba(0, 0, 0, 0.35);
}

.school-name {
  font-size: 28px;
  line-height: 1.1;
  margin-bottom: 10px;
}

.school-full {
  font-size: 10px;
  font-weight: 700;
  opacity: 0.82;
  letter-spacing: 1.2px;
  text-transform: uppercase;
  line-height: 1.4;
}

.school-uiuc {
  background: linear-gradient(135deg, #E84A27 0%, #C9442B 100%);
  color: #FFFFFF;
}

.school-uchicago {
  background: linear-gradient(135deg, #800000 0%, #5C0000 100%);
  color: #FFFFFF;
}

.school-northwestern {
  background: linear-gradient(135deg, #4E2A84 0%, #311760 100%);
  color: #FFFFFF;
}

.school-purdue {
  background: linear-gradient(135deg, #CEB888 0%, #9C7F4A 100%);
  color: #000000;
}

.other-schools {
  text-align: center;
  margin-top: 40px;
  font-size: 14px;
}

/* ───── Footer ───── */

.site-footer {
  border-top: 1px solid var(--border);
  padding: 32px 24px;
  background: var(--bg);
}

.footer-inner {
  max-width: 960px;
  margin: 0 auto;
  display: flex;
  justify-content: space-between;
  align-items: center;
  flex-wrap: wrap;
  gap: 16px;
  color: var(--text-muted);
  font-size: 13px;
}

.footer-links {
  display: inline-flex;
  gap: 18px;
}

.footer-links a {
  color: var(--text-muted);
}

/* ───── Legal page (existing) ───── */

.container {
  max-width: 720px;
  margin: 0 auto;
  padding: 48px 24px 96px;
}

.container h1 {
  font-size: 32px;
  font-weight: 800;
  letter-spacing: -0.5px;
  margin: 0 0 8px;
}

.container .meta {
  color: var(--text-muted);
  font-size: 14px;
  margin-bottom: 32px;
}

.container h2 {
  font-size: 22px;
  font-weight: 800;
  margin-top: 48px;
  margin-bottom: 12px;
  letter-spacing: -0.3px;
}

.container h3 {
  font-size: 17px;
  font-weight: 700;
  margin-top: 28px;
  margin-bottom: 8px;
  color: var(--text);
}

.container p, .container li { color: var(--text); }
.container p { margin: 12px 0; }
.container ul, .container ol { padding-left: 22px; margin: 12px 0; }
.container li { margin-bottom: 6px; }

.container table {
  width: 100%;
  border-collapse: collapse;
  margin: 16px 0;
  font-size: 14px;
}

.container th, .container td {
  border: 1px solid var(--border);
  padding: 10px 12px;
  text-align: left;
  vertical-align: top;
}

.container th {
  background: var(--bg-alt);
  font-weight: 700;
}

.container td.collected {
  text-align: center;
  font-weight: 700;
  width: 100px;
}

.legal-toc {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: 12px;
  padding: 20px 24px;
  margin: 24px 0;
}

.legal-toc ol {
  margin: 0;
  padding-left: 22px;
}

.legal-toc li { margin-bottom: 4px; font-size: 14px; }
.legal-toc li a { color: var(--coral-dark); }

.lang-switch {
  display: inline-flex;
  gap: 8px;
  margin-bottom: 24px;
  padding: 4px;
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: 999px;
}

.lang-switch a {
  padding: 6px 14px;
  border-radius: 999px;
  font-size: 14px;
  font-weight: 600;
  color: var(--text-muted);
}

.lang-switch a.active {
  background: var(--coral);
  color: white;
}

.notice {
  background: var(--butter-soft);
  border: 1px solid var(--butter);
  border-radius: 12px;
  padding: 16px 20px;
  margin: 24px 0;
  color: #6B4E00;
  font-size: 14px;
}

/* ───── Mobile ───── */

@media (max-width: 760px) {
  .site-header { padding: 16px 20px; }
  .site-header .brand { font-size: 19px; }

  .hero { padding: 40px 20px 60px; }
  .hero h1 { font-size: 40px; letter-spacing: -1px; }
  .hero .tagline { font-size: 16px; }
  .hero .badge { font-size: 13px; }

  .section { padding: 56px 20px; }
  .section-title { font-size: 28px; }
  .section-sub { font-size: 15px; margin-bottom: 32px; }

  .use-cases { grid-template-columns: repeat(2, 1fr); gap: 14px; }
  .card { padding: 22px 18px; }
  .card .emoji { font-size: 34px; }
  .card h3 { font-size: 16px; }

  .steps { grid-template-columns: 1fr; gap: 16px; }

  .trust-row { grid-template-columns: repeat(2, 1fr); gap: 12px; }

  .schools { grid-template-columns: repeat(2, 1fr); }

  .footer-inner { flex-direction: column; text-align: center; }
}

@media (max-width: 420px) {
  .hero h1 { font-size: 34px; }
  .use-cases { grid-template-columns: 1fr; }
}