/* ═══════════════════════════════════════════
   LinguaUP — Shared Design System
   Font: Geist / Geist Mono
   ═══════════════════════════════════════════ */

@import url('https://fonts.googleapis.com/css2?family=Playfair+Display:ital,wght@0,400;0,700;0,900;1,400;1,700&family=Geist:wght@300;400;500;600;700;800;900&family=Geist+Mono:wght@300;400;500;600&display=swap');

:root {
  --ink:      #0d0d0d;
  --paper:    #f5f2eb;
  --cream:    #ede9df;
  --white:    #ffffff;
  --accent:   #c8502a;
  --accent2:  #2a6fc8;
  --muted:    #6b6558;
  --border:   #d4cfc4;
  --success:  #2e7d52;
  --warning:  #b8860b;

  --font-display: 'Playfair Display', serif;
  --font-body:    'Geist', sans-serif;
  --font-mono:    'Geist Mono', monospace;
}

*, *::before, *::after { margin: 0; padding: 0; box-sizing: border-box; }
html { scroll-behavior: smooth; -webkit-text-size-adjust: 100%; }

body {
  font-family: var(--font-body);
  background: var(--paper);
  color: var(--ink);
  line-height: 1.6;
  min-height: 100vh;
}

/* Noise overlay */
body::before {
  content: '';
  position: fixed;
  inset: 0;
  background-image: url("data:image/svg+xml,%3Csvg viewBox='0 0 200 200' xmlns='http://www.w3.org/2000/svg'%3E%3Cfilter id='n'%3E%3CfeTurbulence type='fractalNoise' baseFrequency='0.9' numOctaves='4' stitchTiles='stitch'/%3E%3C/filter%3E%3Crect width='100%25' height='100%25' filter='url(%23n)' opacity='0.04'/%3E%3C/svg%3E");
  pointer-events: none;
  z-index: 9999;
  opacity: 0.45;
}

/* ── TYPOGRAPHY ── */
h1,h2,h3,h4 { font-family: var(--font-display); letter-spacing: -0.03em; line-height: 1.1; }
code, .mono  { font-family: var(--font-mono); }

/* ── SHARED NAV ── */
.lu-nav {
  position: sticky;
  top: 0;
  z-index: 200;
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 16px 48px;
  background: rgba(245,242,235,0.92);
  backdrop-filter: blur(14px);
  -webkit-backdrop-filter: blur(14px);
  border-bottom: 1px solid var(--border);
  gap: 16px;
}

.lu-logo {
  font-family: var(--font-display);
  font-weight: 900;
  font-size: 20px;
  color: var(--ink);
  text-decoration: none;
  white-space: nowrap;
}
.lu-logo span { color: var(--accent); }

.lu-nav-links {
  display: flex;
  gap: 32px;
  list-style: none;
  align-items: center;
}
.lu-nav-links a {
  font-family: var(--font-mono);
  font-size: 12px;
  font-weight: 400;
  color: var(--muted);
  text-decoration: none;
  letter-spacing: 0.05em;
  transition: color 0.2s;
}
.lu-nav-links a:hover { color: var(--ink); }

.lu-btn {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 10px 22px;
  border-radius: 100px;
  font-family: var(--font-mono);
  font-size: 12px;
  font-weight: 500;
  text-decoration: none;
  cursor: pointer;
  transition: all 0.18s;
  border: 1.5px solid transparent;
  white-space: nowrap;
}
.lu-btn-primary {
  background: var(--ink);
  color: var(--paper);
  border-color: var(--ink);
}
.lu-btn-primary:hover { background: var(--accent); border-color: var(--accent); }

.lu-btn-ghost {
  background: transparent;
  color: var(--ink);
  border-color: var(--border);
}
.lu-btn-ghost:hover { border-color: var(--ink); background: var(--cream); }

.lu-btn-accent {
  background: var(--accent);
  color: white;
  border-color: var(--accent);
}
.lu-btn-accent:hover { background: #b5431f; border-color: #b5431f; }

/* ── SHARED FOOTER ── */
.lu-footer {
  background: var(--cream);
  border-top: 1px solid var(--border);
  padding: 36px 48px;
  display: flex;
  justify-content: space-between;
  align-items: center;
  flex-wrap: wrap;
  gap: 16px;
}
.lu-footer p {
  font-family: var(--font-mono);
  font-size: 11px;
  color: var(--muted);
  letter-spacing: 0.05em;
}

/* ── LABEL / TAG ── */
.lu-label {
  font-family: var(--font-mono);
  font-size: 10px;
  font-weight: 500;
  letter-spacing: 0.14em;
  text-transform: uppercase;
  color: var(--accent);
  display: flex;
  align-items: center;
  gap: 8px;
}
.lu-label::before {
  content: '';
  display: block;
  width: 18px;
  height: 1px;
  background: var(--accent);
}

/* ── CATEGORY COLORS ── */
.cat-listening  { --cat: #e8603a; --cat-bg: #fde8e0; }
.cat-practice   { --cat: #d4a03a; --cat-bg: #fdf6e0; }
.cat-reading    { --cat: #3a78d8; --cat-bg: #dff0fd; }
.cat-writing    { --cat: #3aaa6e; --cat-bg: #e0fdec; }

/* ── MOBILE NAV ── */
.lu-hamburger {
  display: none;
  flex-direction: column;
  gap: 5px;
  cursor: pointer;
  padding: 4px;
  background: none;
  border: none;
}
.lu-hamburger span {
  display: block;
  width: 22px;
  height: 1.5px;
  background: var(--ink);
  transition: all 0.2s;
}

@media (max-width: 768px) {
  .lu-nav { padding: 14px 20px; }
  .lu-nav-links { display: none; }
  .lu-hamburger { display: flex; }
  .lu-footer { padding: 28px 20px; flex-direction: column; text-align: center; }
}