:root {
  --primary: #2563eb;
  --primary-dark: #1d4ed8;
  --bg: #f5f7fb;
  --card-bg: #ffffff;
  --text: #1f2937;
  --text-muted: #6b7280;
  --border: #e5e7eb;
  --radius: 12px;
}

* { box-sizing: border-box; }

body {
  margin: 0;
  font-family: "Sarabun", "Segoe UI", Tahoma, sans-serif;
  background: var(--bg);
  color: var(--text);
}

a { color: inherit; text-decoration: none; }

header.site-header {
  background: linear-gradient(135deg, var(--primary), var(--primary-dark));
  color: #fff;
  padding: 20px 16px;
}

.header-inner {
  max-width: 1100px;
  margin: 0 auto;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
  flex-wrap: wrap;
}

.brand {
  font-size: 1.5rem;
  font-weight: 700;
}

nav.main-nav {
  display: flex;
  gap: 18px;
  font-size: 0.95rem;
}
nav.main-nav a { opacity: 0.9; }
nav.main-nav a:hover { opacity: 1; text-decoration: underline; }

.auth-area {
  display: flex;
  align-items: center;
  gap: 10px;
}

.hero {
  max-width: 1100px;
  margin: 24px auto 0;
  padding: 0 16px;
}

.search-box {
  width: 100%;
  padding: 14px 18px;
  border-radius: 999px;
  border: 1px solid var(--border);
  font-size: 1rem;
  box-shadow: 0 1px 3px rgba(0,0,0,0.06);
}

.container {
  max-width: 1100px;
  margin: 0 auto;
  padding: 24px 16px 60px;
}

.ad-slot {
  max-width: 1100px;
  margin: 20px auto;
  padding: 8px 16px;
  text-align: center;
  color: var(--text-muted);
  font-size: 0.8rem;
}
.ad-slot .ad-label { margin-bottom: 6px; }

.category-section {
  margin-bottom: 36px;
}

.category-title {
  font-size: 1.25rem;
  font-weight: 700;
  margin-bottom: 14px;
  display: flex;
  align-items: center;
  gap: 8px;
}

.site-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(230px, 1fr));
  gap: 14px;
}

.site-card {
  background: var(--card-bg);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 16px;
  transition: transform 0.15s ease, box-shadow 0.15s ease;
  display: block;
}
.site-card:hover {
  transform: translateY(-2px);
  box-shadow: 0 6px 18px rgba(0,0,0,0.08);
}
.site-card .name {
  font-weight: 600;
  margin-bottom: 4px;
}
.site-card .desc {
  font-size: 0.85rem;
  color: var(--text-muted);
}

.btn {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 8px 16px;
  border-radius: 8px;
  border: 1px solid var(--border);
  background: #fff;
  color: var(--text);
  font-size: 0.9rem;
  cursor: pointer;
}
.btn:hover { background: #f3f4f6; }
.btn.google { border-color: #dadce0; }
.btn.facebook { background: #1877f2; color: #fff; border-color: #1877f2; }
.btn.facebook:hover { background: #166fe0; }

.user-chip {
  display: flex;
  align-items: center;
  gap: 8px;
  background: rgba(255,255,255,0.15);
  padding: 6px 12px;
  border-radius: 999px;
  font-size: 0.9rem;
}
.user-chip img {
  width: 26px; height: 26px; border-radius: 50%;
}

footer.site-footer {
  text-align: center;
  padding: 24px 16px;
  color: var(--text-muted);
  font-size: 0.85rem;
}

.no-result {
  color: var(--text-muted);
  padding: 24px;
  text-align: center;
}

/* --- Tools page --- */
.tool-tabs {
  display: flex;
  gap: 10px;
  margin-bottom: 20px;
}
.tool-tab {
  padding: 10px 20px;
  border-radius: 999px;
  border: 1px solid var(--border);
  background: #fff;
  cursor: pointer;
  font-weight: 600;
}
.tool-tab.active {
  background: var(--primary);
  color: #fff;
  border-color: var(--primary);
}

.tool-panel {
  background: var(--card-bg);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 24px;
  max-width: 560px;
}
.tool-panel input[type="text"] {
  width: 100%;
  padding: 12px 14px;
  border-radius: 8px;
  border: 1px solid var(--border);
  font-size: 1rem;
  margin-bottom: 12px;
}
.tool-panel .primary-btn {
  background: var(--primary);
  color: #fff;
  border: none;
  padding: 12px 22px;
  border-radius: 8px;
  font-size: 1rem;
  cursor: pointer;
}
.tool-panel .primary-btn:hover { background: var(--primary-dark); }

#qrResult, #shortResult {
  margin-top: 20px;
}

.result-box {
  display: flex;
  align-items: center;
  gap: 16px;
  flex-wrap: wrap;
}

.short-link-row {
  display: flex;
  gap: 8px;
  align-items: center;
}
.short-link-row input {
  flex: 1;
}

/* --- Student Quizzz live quiz game --- */
.quiz-editor {
  max-width: 720px;
}
.question-block {
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 16px;
  margin-bottom: 16px;
  background: #fafbfc;
}
.question-block .q-row {
  display: flex;
  gap: 8px;
  align-items: center;
  margin-bottom: 10px;
}
.question-block input[type="text"] {
  padding: 10px 12px;
  border-radius: 8px;
  border: 1px solid var(--border);
  font-size: 0.95rem;
}
.question-block .q-text {
  flex: 1;
}
.option-row {
  display: flex;
  gap: 8px;
  align-items: center;
  margin-bottom: 8px;
}
.option-row input[type="text"] {
  flex: 1;
}
.field-row {
  display: flex;
  gap: 12px;
  align-items: center;
  margin-top: 10px;
  font-size: 0.9rem;
  color: var(--text-muted);
}
.field-row input[type="number"] {
  width: 70px;
  padding: 6px 8px;
  border-radius: 6px;
  border: 1px solid var(--border);
}
.icon-btn {
  border: none;
  background: transparent;
  cursor: pointer;
  color: var(--text-muted);
  font-size: 1rem;
  padding: 4px 8px;
}
.icon-btn:hover { color: #dc2626; }

.quiz-card-row {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 14px 18px;
  background: var(--card-bg);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  margin-bottom: 10px;
}
.quiz-card-row .title { font-weight: 600; }
.quiz-card-row .meta { font-size: 0.85rem; color: var(--text-muted); }
.quiz-card-row .actions { display: flex; gap: 8px; }

.pin-display {
  font-size: 3rem;
  font-weight: 800;
  letter-spacing: 6px;
  color: var(--primary);
  text-align: center;
  margin: 12px 0;
}

.lobby-players {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  margin: 16px 0;
}
.player-chip {
  background: #eef2ff;
  color: var(--primary-dark);
  padding: 6px 14px;
  border-radius: 999px;
  font-size: 0.9rem;
}

.question-stage {
  text-align: center;
  padding: 20px;
}
.question-stage .q-text-display {
  font-size: 1.6rem;
  font-weight: 700;
  margin-bottom: 24px;
}
.timer-badge {
  display: inline-block;
  background: var(--primary);
  color: #fff;
  padding: 6px 18px;
  border-radius: 999px;
  font-weight: 700;
  margin-bottom: 20px;
}

.answer-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 14px;
  max-width: 700px;
  margin: 0 auto;
}
.answer-btn {
  padding: 28px 16px;
  border: none;
  border-radius: var(--radius);
  color: #fff;
  font-size: 1.15rem;
  font-weight: 700;
  cursor: pointer;
  transition: transform 0.1s ease;
}
.answer-btn:hover { transform: scale(1.02); }
.answer-btn:disabled { opacity: 0.6; cursor: default; }
.answer-btn.color-0 { background: #e21b3c; }
.answer-btn.color-1 { background: #1368ce; }
.answer-btn.color-2 { background: #d89e00; }
.answer-btn.color-3 { background: #26890c; }

.leaderboard-list {
  max-width: 480px;
  margin: 0 auto;
}
.leaderboard-row {
  display: flex;
  justify-content: space-between;
  padding: 10px 18px;
  background: var(--card-bg);
  border: 1px solid var(--border);
  border-radius: 10px;
  margin-bottom: 8px;
}
.leaderboard-row.me {
  border-color: var(--primary);
  background: #eef2ff;
}
.leaderboard-row .rank { color: var(--text-muted); margin-right: 10px; }

.reveal-banner {
  padding: 20px;
  border-radius: var(--radius);
  text-align: center;
  font-size: 1.3rem;
  font-weight: 700;
  color: #fff;
  margin-bottom: 20px;
}
.reveal-banner.correct { background: #26890c; }
.reveal-banner.wrong { background: #e21b3c; }