/* ===== Reset & Base ===== */
*, *::before, *::after { margin: 0; padding: 0; box-sizing: border-box; }

:root {
  --color-bg: #ffffff;
  --color-surface: #f8f9fa;
  --color-border: #e9ecef;
  --color-text: #1a1a2e;
  --color-text-secondary: #6c757d;
  --color-accent: #2563eb;
  --color-accent-hover: #1d4ed8;
  --color-gold: #f59e0b;
  --color-silver: #94a3b8;
  --color-bronze: #d97706;
  --font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, 'Helvetica Neue', Arial, sans-serif;
  --max-width: 960px;
  --radius: 12px;
  --radius-sm: 8px;
  --shadow: 0 1px 3px rgba(0,0,0,0.08), 0 1px 2px rgba(0,0,0,0.06);
  --shadow-md: 0 4px 6px rgba(0,0,0,0.07), 0 2px 4px rgba(0,0,0,0.06);
  --shadow-lg: 0 10px 25px rgba(0,0,0,0.1);
}

html { scroll-behavior: smooth; }

body {
  font-family: var(--font-family);
  background: var(--color-bg);
  color: var(--color-text);
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
}

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

img { max-width: 100%; height: auto; }
img.hero-icon { max-width: 80px; }

/* ===== Layout ===== */
.container {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0 1.5rem;
}

/* ===== Nav ===== */
.nav {
  position: sticky;
  top: 0;
  z-index: 100;
  background: rgba(255,255,255,0.92);
  backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--color-border);
}

.nav .container {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 60px;
}

.nav-brand {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  font-size: 1.25rem;
  font-weight: 700;
  color: var(--color-text);
  text-decoration: none;
}

.nav-brand:hover { text-decoration: none; }

.nav-brand img {
  width: 32px;
  height: 32px;
  border-radius: 8px;
}

.nav-links {
  display: flex;
  align-items: center;
  gap: 1.5rem;
  list-style: none;
}

.nav-links a {
  color: var(--color-text-secondary);
  font-size: 0.9rem;
  font-weight: 500;
  transition: color 0.2s;
}

.nav-links a:hover {
  color: var(--color-text);
  text-decoration: none;
}

/* ===== Hero ===== */
.hero {
  text-align: center;
  padding: 5rem 1.5rem 4rem;
}

.hero-icon {
  display: block;
  width: 80px;
  height: 80px;
  margin: 0 auto 1rem;
}

.hero h1 {
  font-size: 3rem;
  font-weight: 800;
  letter-spacing: -0.02em;
  margin-bottom: 0.75rem;
}

.hero p {
  font-size: 1.2rem;
  color: var(--color-text-secondary);
  max-width: 520px;
  margin: 0 auto 2.5rem;
}

.store-buttons {
  display: flex;
  justify-content: center;
  gap: 1rem;
  flex-wrap: wrap;
}

.store-btn {
  display: inline-flex;
  align-items: center;
  gap: 0.6rem;
  padding: 0.75rem 1.5rem;
  background: var(--color-text);
  color: #fff;
  border-radius: var(--radius);
  font-size: 0.95rem;
  font-weight: 600;
  transition: transform 0.15s, box-shadow 0.15s;
  text-decoration: none;
}

.store-btn:hover {
  transform: translateY(-2px);
  box-shadow: var(--shadow-lg);
  text-decoration: none;
  color: #fff;
}

.store-btn svg { width: 24px; height: 24px; flex-shrink: 0; }

/* ===== Features ===== */
.features {
  padding: 4rem 0;
  background: var(--color-surface);
  border-top: 1px solid var(--color-border);
  border-bottom: 1px solid var(--color-border);
}

.features-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
  gap: 2rem;
}

.feature-card {
  background: var(--color-bg);
  border: 1px solid var(--color-border);
  border-radius: var(--radius);
  padding: 1.75rem;
  box-shadow: var(--shadow);
}

.feature-icon {
  font-size: 2rem;
  margin-bottom: 0.75rem;
}

.feature-card h3 {
  font-size: 1.1rem;
  font-weight: 700;
  margin-bottom: 0.5rem;
}

.feature-card p {
  font-size: 0.9rem;
  color: var(--color-text-secondary);
  line-height: 1.5;
}

/* ===== CTA Banner ===== */
.cta-banner {
  text-align: center;
  padding: 4rem 1.5rem;
}

.cta-banner h2 {
  font-size: 2rem;
  font-weight: 800;
  margin-bottom: 0.5rem;
}

.cta-banner p {
  color: var(--color-text-secondary);
  margin-bottom: 2rem;
  font-size: 1.1rem;
}

/* ===== Footer ===== */
.footer {
  border-top: 1px solid var(--color-border);
  padding: 2rem 0;
  text-align: center;
  color: var(--color-text-secondary);
  font-size: 0.85rem;
}

.footer-links {
  display: flex;
  justify-content: center;
  gap: 1.5rem;
  list-style: none;
  margin-bottom: 0.75rem;
}

.footer-links a {
  color: var(--color-text-secondary);
  font-size: 0.85rem;
}

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

/* ===== Leaderboard Page ===== */
.page-header {
  text-align: center;
  padding: 3rem 1.5rem 2rem;
}

.page-header h1 {
  font-size: 2.2rem;
  font-weight: 800;
}

.page-header p {
  color: var(--color-text-secondary);
  margin-top: 0.5rem;
}

/* Tab bar */
.tabs {
  display: flex;
  gap: 0.25rem;
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius);
  padding: 4px;
  overflow-x: auto;
}

.tab-btn {
  flex: 1;
  padding: 0.6rem 1rem;
  border: none;
  border-radius: var(--radius-sm);
  background: transparent;
  font-family: inherit;
  font-size: 0.85rem;
  font-weight: 600;
  color: var(--color-text-secondary);
  cursor: pointer;
  transition: background 0.2s, color 0.2s;
  white-space: nowrap;
}

.tab-btn:hover { background: rgba(0,0,0,0.04); }

.tab-btn.active {
  background: var(--color-bg);
  color: var(--color-text);
  box-shadow: var(--shadow);
}

/* Scope breadcrumb */
.scope-bar {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  padding: 1rem 0;
  flex-wrap: wrap;
}

.scope-chip {
  display: inline-flex;
  align-items: center;
  gap: 0.3rem;
  padding: 0.35rem 0.85rem;
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: 20px;
  font-size: 0.8rem;
  font-weight: 600;
  color: var(--color-text-secondary);
  cursor: pointer;
  transition: background 0.2s, border-color 0.2s;
}

.scope-chip:hover { border-color: var(--color-accent); color: var(--color-accent); }
.scope-chip.active { background: var(--color-accent); color: #fff; border-color: var(--color-accent); }

/* Countdown */
.countdown-bar {
  text-align: center;
  padding: 0.75rem;
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-sm);
  margin-bottom: 1rem;
  font-size: 0.85rem;
  color: var(--color-text-secondary);
}

.countdown-bar strong {
  color: var(--color-text);
  font-variant-numeric: tabular-nums;
}

/* Score table */
.score-table {
  width: 100%;
  border-collapse: collapse;
}

.score-table th {
  text-align: left;
  padding: 0.6rem 0.75rem;
  font-size: 0.75rem;
  font-weight: 600;
  color: var(--color-text-secondary);
  text-transform: uppercase;
  letter-spacing: 0.05em;
  border-bottom: 2px solid var(--color-border);
}

.score-table th:last-child { text-align: right; }

.score-table td {
  padding: 0.65rem 0.75rem;
  font-size: 0.9rem;
  border-bottom: 1px solid var(--color-border);
}

.score-table td:last-child {
  text-align: right;
  font-weight: 700;
  font-variant-numeric: tabular-nums;
}

.score-table tr:last-child td { border-bottom: none; }

.rank-cell {
  font-weight: 700;
  width: 3rem;
}

.rank-1 .rank-cell { color: var(--color-gold); }
.rank-2 .rank-cell { color: var(--color-silver); }
.rank-3 .rank-cell { color: var(--color-bronze); }

.medal { margin-right: 0.25rem; }

.name-cell {
  display: flex;
  align-items: center;
  gap: 0.4rem;
}

/* Browse toggle button */
.browse-toggle {
  display: inline-flex;
  align-items: center;
  gap: 0.3rem;
  padding: 0.35rem 0.85rem;
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: 20px;
  font-family: inherit;
  font-size: 0.8rem;
  font-weight: 600;
  color: var(--color-text-secondary);
  cursor: pointer;
  transition: background 0.2s, border-color 0.2s, color 0.2s;
}

.browse-toggle:hover {
  border-color: var(--color-accent);
  color: var(--color-accent);
}

.browse-toggle.active {
  background: var(--color-accent);
  color: #fff;
  border-color: var(--color-accent);
}

/* Browse panel */
.browse-panel {
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius);
  margin-bottom: 1rem;
  overflow: hidden;
}

.browse-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 0.75rem 1rem;
  border-bottom: 1px solid var(--color-border);
  font-size: 0.85rem;
  font-weight: 700;
  color: var(--color-text);
}

.browse-close {
  background: none;
  border: none;
  font-size: 1.2rem;
  color: var(--color-text-secondary);
  cursor: pointer;
  padding: 0 0.25rem;
  line-height: 1;
}

.browse-close:hover { color: var(--color-text); }

.browse-list {
  max-height: 320px;
  overflow-y: auto;
  padding: 0.25rem 0;
}

.browse-item {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 0.6rem 1rem;
  font-size: 0.85rem;
  color: var(--color-text);
  cursor: pointer;
  transition: background 0.15s;
  border: none;
  background: none;
  width: 100%;
  text-align: left;
  font-family: inherit;
}

.browse-item:hover { background: rgba(0,0,0,0.04); }

.browse-item .browse-chevron {
  color: var(--color-text-secondary);
  font-size: 0.75rem;
  flex-shrink: 0;
}

.browse-empty {
  text-align: center;
  padding: 1.5rem 1rem;
  color: var(--color-text-secondary);
  font-size: 0.85rem;
}

/* Loading / empty / error states */
.state-message {
  text-align: center;
  padding: 3rem 1.5rem;
  color: var(--color-text-secondary);
}

.state-message .icon { font-size: 2rem; margin-bottom: 0.5rem; }

.spinner {
  width: 28px;
  height: 28px;
  border: 3px solid var(--color-border);
  border-top-color: var(--color-accent);
  border-radius: 50%;
  animation: spin 0.8s linear infinite;
  margin: 0 auto 0.75rem;
}

@keyframes spin { to { transform: rotate(360deg); } }

/* ===== Challenge / Invite page (served by Cloud Function) ===== */
.dynamic-page {
  min-height: 100vh;
  display: flex;
  align-items: center;
  justify-content: center;
  padding: 2rem 1.5rem;
}

.card {
  background: var(--color-bg);
  border: 1px solid var(--color-border);
  border-radius: var(--radius);
  padding: 2rem;
  box-shadow: var(--shadow-md);
  max-width: 420px;
  width: 100%;
  text-align: center;
}

.card h1 { font-size: 1.5rem; margin-bottom: 0.5rem; }
.card .subtitle { color: var(--color-text-secondary); margin-bottom: 1.5rem; }

.card .big-score {
  font-size: 2.5rem;
  font-weight: 800;
  color: var(--color-accent);
  margin: 0.5rem 0;
}

.card .meta {
  font-size: 0.85rem;
  color: var(--color-text-secondary);
  margin-bottom: 1.5rem;
}

.btn-primary {
  display: block;
  width: 100%;
  padding: 0.85rem;
  background: var(--color-text);
  color: #fff;
  border: none;
  border-radius: var(--radius-sm);
  font-family: inherit;
  font-size: 1rem;
  font-weight: 600;
  cursor: pointer;
  text-decoration: none;
  text-align: center;
  transition: transform 0.15s, box-shadow 0.15s;
  margin-bottom: 0.5rem;
}

.btn-primary:hover {
  transform: translateY(-1px);
  box-shadow: var(--shadow-md);
  text-decoration: none;
  color: #fff;
}

.btn-secondary {
  display: block;
  width: 100%;
  padding: 0.85rem;
  background: transparent;
  color: var(--color-text);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-sm);
  font-family: inherit;
  font-size: 0.9rem;
  font-weight: 600;
  cursor: pointer;
  text-decoration: none;
  text-align: center;
  transition: background 0.15s;
  margin-bottom: 0.5rem;
}

.btn-secondary:hover {
  background: var(--color-surface);
  text-decoration: none;
}

/* Badge (for challenge rules) */
.badge {
  display: inline-block;
  padding: 0.25rem 0.75rem;
  border-radius: 20px;
  font-size: 0.75rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.03em;
}

.badge-green { background: #dcfce7; color: #166534; }
.badge-orange { background: #fef3c7; color: #92400e; }
.badge-red { background: #fee2e2; color: #991b1b; }

/* ===== Privacy page ===== */
.content-page {
  padding: 3rem 0 4rem;
}

.content-page h1 { font-size: 2rem; font-weight: 800; margin-bottom: 1.5rem; }
.content-page h2 { font-size: 1.3rem; font-weight: 700; margin-top: 2rem; margin-bottom: 0.75rem; }
.content-page p { margin-bottom: 1rem; color: var(--color-text-secondary); }
.content-page ul { margin: 0.5rem 0 1rem 1.5rem; color: var(--color-text-secondary); }
.content-page li { margin-bottom: 0.4rem; }

/* ===== 404 ===== */
.page-404 {
  min-height: 80vh;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  text-align: center;
  padding: 2rem;
}

.page-404 .big { font-size: 5rem; font-weight: 800; color: var(--color-border); }
.page-404 h1 { font-size: 1.5rem; margin-bottom: 0.5rem; }
.page-404 p { color: var(--color-text-secondary); margin-bottom: 1.5rem; }

/* ===== Responsive ===== */
@media (max-width: 640px) {
  .hero h1 { font-size: 2.2rem; }
  .hero p { font-size: 1rem; }
  .hero { padding: 3rem 1.5rem 2.5rem; }

  .features-grid { grid-template-columns: 1fr; }

  .store-buttons { flex-direction: column; align-items: center; }
  .store-btn { width: 100%; max-width: 280px; justify-content: center; }

  .nav-links { gap: 1rem; }
  .nav-links a { font-size: 0.8rem; }

  .score-table { font-size: 0.85rem; }
  .score-table th, .score-table td { padding: 0.5rem; }

  .tabs { gap: 0; }
  .tab-btn { padding: 0.5rem 0.6rem; font-size: 0.8rem; }
}