:root {
  --primary: #3b82f6;
  --primary-dark: #2563eb;
  --secondary: #f59e0b;
  --bg: #0f172a;
  --surface: #1e293b;
  --border: rgba(59, 130, 246, 0.15);
  --text: #f8fafc;
  --text-muted: #94a3b8;
  --success: #10b981;
  --radius: 12px;
  --shadow: 0 1px 3px rgba(0,0,0,0.08), 0 4px 16px rgba(0,0,0,0.06);
  --shadow-hover: 0 4px 12px rgba(37,99,235,0.15);
}

* { box-sizing: border-box; margin: 0; padding: 0; }

body {
  font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', 'Noto Sans Thai', sans-serif;
  background: var(--bg);
  color: var(--text);
  line-height: 1.6;
}

.container { max-width: 960px; margin: 0 auto; padding: 0 16px; }

/* Header */
header {
  background: linear-gradient(135deg, #1e40af 0%, #2563eb 50%, #0ea5e9 100%);
  color: white;
  padding: 32px 0 24px;
  text-align: center;
}
header h1 { font-size: 2rem; font-weight: 800; letter-spacing: -0.5px; }
.subtitle { opacity: 0.85; margin-top: 4px; font-size: 0.95rem; }
.last-updated {
  margin-top: 8px;
  font-size: 0.78rem;
  opacity: 0.7;
  background: rgba(255,255,255,0.15);
  display: inline-block;
  padding: 2px 10px;
  border-radius: 20px;
}

/* Ad */
.ad-container { margin: 16px 0; }
.ad-placeholder {
  background: #f1f5f9;
  border: 2px dashed var(--border);
  border-radius: var(--radius);
  text-align: center;
  padding: 20px;
  color: var(--text-muted);
  font-size: 0.8rem;
  min-height: 90px;
  display: flex;
  align-items: center;
  justify-content: center;
}

/* Converter Card */
.converter-card {
  background: var(--surface);
  border-radius: var(--radius);
  box-shadow: var(--shadow);
  padding: 24px;
  margin: 16px 0;
}

.converter-row {
  display: flex;
  align-items: flex-end;
  gap: 12px;
  flex-wrap: wrap;
}

.input-group {
  display: flex;
  flex-direction: column;
  gap: 6px;
  flex: 1;
  min-width: 140px;
}

.input-group label {
  font-size: 0.8rem;
  font-weight: 600;
  color: var(--text-muted);
  text-transform: uppercase;
  letter-spacing: 0.5px;
}

.input-group input,
.select-wrapper select {
  padding: 10px 14px;
  border: 1.5px solid var(--border);
  border-radius: 8px;
  font-size: 1rem;
  color: var(--text);
  background: var(--surface);
  outline: none;
  transition: border-color 0.2s;
  width: 100%;
}

.input-group input:focus,
.select-wrapper select:focus {
  border-color: var(--primary);
  box-shadow: 0 0 0 3px rgba(37,99,235,0.1);
}

.select-wrapper { position: relative; }

.swap-btn {
  background: var(--bg);
  border: 1.5px solid var(--border);
  border-radius: 50%;
  width: 40px;
  height: 40px;
  font-size: 1.2rem;
  cursor: pointer;
  transition: all 0.2s;
  flex-shrink: 0;
  margin-bottom: 2px;
}
.swap-btn:hover { background: var(--primary); color: white; border-color: var(--primary); }

/* Result */
.result-display {
  margin: 20px 0 16px;
  padding: 20px;
  background: linear-gradient(135deg, #eff6ff, #f0fdf4);
  border-radius: 10px;
  border: 1px solid #bfdbfe;
  text-align: center;
  min-height: 72px;
}
.result-amount {
  font-size: 2rem;
  font-weight: 800;
  color: var(--primary);
  letter-spacing: -1px;
}
.result-rate { font-size: 0.85rem; color: var(--text-muted); margin-top: 4px; }

.converter-actions {
  display: flex;
  gap: 10px;
  flex-wrap: wrap;
}

.btn-primary, .btn-secondary {
  padding: 10px 20px;
  border-radius: 8px;
  font-size: 0.9rem;
  font-weight: 600;
  cursor: pointer;
  border: none;
  transition: all 0.2s;
}
.btn-primary {
  background: var(--primary);
  color: white;
  flex: 1;
}
.btn-primary:hover { background: var(--primary-dark); box-shadow: var(--shadow-hover); }
.btn-secondary {
  background: var(--bg);
  color: var(--text);
  border: 1.5px solid var(--border);
}
.btn-secondary:hover { border-color: var(--primary); color: var(--primary); }

/* Two-col layout */
.two-col {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 16px;
  margin: 16px 0;
}

/* Multi-currency */
.multi-card, .chart-card, .favorites-card, .popular-card {
  background: var(--surface);
  border-radius: var(--radius);
  box-shadow: var(--shadow);
  padding: 20px;
}
.multi-card { margin: 16px 0; }
.popular-card { margin: 0 0 16px; }

.multi-card h2, .chart-card h2, .favorites-card h2, .popular-card h2 {
  font-size: 1rem;
  font-weight: 700;
  margin-bottom: 4px;
}
.section-desc { font-size: 0.8rem; color: var(--text-muted); margin-bottom: 16px; }

.multi-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(140px, 1fr));
  gap: 10px;
}

.multi-item {
  background: var(--bg);
  border-radius: 8px;
  padding: 12px;
  text-align: center;
  border: 1px solid var(--border);
  transition: all 0.2s;
  cursor: pointer;
}
.multi-item:hover { border-color: var(--primary); background: #eff6ff; }
.multi-item .flag { font-size: 1.4rem; }
.multi-item .code { font-size: 0.7rem; font-weight: 700; color: var(--text-muted); margin: 2px 0; }
.multi-item .value { font-size: 1rem; font-weight: 700; color: var(--text); }

/* Chart */
.chart-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: 8px;
  flex-wrap: wrap;
  gap: 8px;
}
#chart-label { font-weight: 600; font-size: 0.9rem; color: var(--primary); }
.chart-stats { font-size: 0.75rem; color: var(--text-muted); }
.chart-wrapper { position: relative; height: 200px; }
.chart-loading { text-align: center; color: var(--text-muted); font-size: 0.8rem; padding: 16px; }

/* Favorites */
.favorites-list { display: flex; flex-direction: column; gap: 8px; margin-top: 12px; }
.fav-item {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 10px 12px;
  background: var(--bg);
  border-radius: 8px;
  border: 1px solid var(--border);
  cursor: pointer;
  transition: all 0.2s;
  font-size: 0.88rem;
}
.fav-item:hover { border-color: var(--primary); background: #eff6ff; }
.fav-pair { font-weight: 600; }
.fav-rate { color: var(--text-muted); font-size: 0.8rem; }
.fav-remove {
  background: none;
  border: none;
  cursor: pointer;
  color: var(--text-muted);
  font-size: 1rem;
  padding: 2px 4px;
  border-radius: 4px;
}
.fav-remove:hover { color: #ef4444; background: #fee2e2; }
.empty-msg { color: var(--text-muted); font-size: 0.85rem; text-align: center; padding: 16px 0; }

/* Popular pairs */
.popular-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(160px, 1fr));
  gap: 10px;
  margin-top: 12px;
}
.popular-item {
  background: var(--bg);
  border: 1px solid var(--border);
  border-radius: 8px;
  padding: 12px;
  cursor: pointer;
  transition: all 0.2s;
  text-align: center;
}
.popular-item:hover { border-color: var(--primary); background: #eff6ff; box-shadow: var(--shadow-hover); }
.popular-item .pair-name { font-weight: 700; font-size: 0.9rem; color: var(--primary); }
.popular-item .pair-rate { font-size: 0.82rem; color: var(--text-muted); margin-top: 2px; }
.popular-item .pair-change {
  font-size: 0.75rem;
  margin-top: 4px;
  font-weight: 600;
  padding: 1px 6px;
  border-radius: 4px;
  display: inline-block;
}
.change-up { color: var(--success); background: #d1fae5; }
.change-down { color: #ef4444; background: #fee2e2; }

/* Footer */
footer {
  background: #1e293b;
  color: #94a3b8;
  text-align: center;
  padding: 20px;
  font-size: 0.8rem;
  margin-top: 32px;
  line-height: 2;
}

/* Loading state */
.loading { opacity: 0.5; pointer-events: none; }
.spinner { display: inline-block; animation: spin 1s linear infinite; }
@keyframes spin { to { transform: rotate(360deg); } }

/* Responsive */
@media (max-width: 640px) {
  header h1 { font-size: 1.5rem; }
  .two-col { grid-template-columns: 1fr; }
  .converter-row { flex-direction: column; }
  .swap-btn { align-self: center; transform: rotate(90deg); }
  .result-amount { font-size: 1.5rem; }
  .multi-grid { grid-template-columns: repeat(2, 1fr); }
}