:root {
  --primary: #0a7c7a;
  --primary-dark: #065b59;
  --primary-light: #e0f5f4;
  --accent: #ff6b35;
  --accent-light: #fff0e8;
  --gray-50: #f9fafb;
  --gray-100: #f3f4f6;
  --gray-200: #e5e7eb;
  --gray-300: #d1d5db;
  --gray-400: #9ca3af;
  --gray-500: #6b7280;
  --gray-600: #4b5563;
  --gray-700: #374151;
  --gray-800: #1f2937;
  --gray-900: #111827;
  --white: #ffffff;
  --shadow: 0 1px 3px rgba(0,0,0,0.1), 0 1px 2px rgba(0,0,0,0.06);
  --shadow-md: 0 4px 6px rgba(0,0,0,0.1), 0 2px 4px rgba(0,0,0,0.06);
  --shadow-lg: 0 10px 15px rgba(0,0,0,0.1), 0 4px 6px rgba(0,0,0,0.05);
  --radius: 8px;
  --radius-lg: 12px;
  --transition: 200ms ease;
}

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

html { scroll-behavior: smooth; }

body {
  font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen, Ubuntu, sans-serif;
  color: var(--gray-800);
  background: var(--gray-50);
  line-height: 1.6;
  min-height: 100vh;
  display: flex;
  flex-direction: column;
}

a { color: var(--primary); text-decoration: none; transition: color var(--transition); }
a:hover { color: var(--primary-dark); }
img { max-width: 100%; height: auto; }

.container {
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 20px;
}

/* ─── Header ─── */
.header {
  background: var(--white);
  border-bottom: 1px solid var(--gray-200);
  position: sticky;
  top: 0;
  z-index: 100;
}
.header-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 64px;
  gap: 20px;
}
.logo {
  font-size: 1.5rem;
  font-weight: 800;
  color: var(--primary);
  letter-spacing: -0.5px;
}
.logo span { color: var(--accent); }
.nav { display: flex; gap: 8px; align-items: center; }
.nav a {
  padding: 8px 16px;
  border-radius: var(--radius);
  color: var(--gray-600);
  font-weight: 500;
  font-size: 0.9rem;
}
.nav a:hover, .nav a.active {
  background: var(--primary-light);
  color: var(--primary);
}

/* ─── Hero ─── */
.hero {
  background: linear-gradient(135deg, var(--primary) 0%, var(--primary-dark) 100%);
  color: var(--white);
  padding: 60px 0;
  text-align: center;
}
.hero h1 { font-size: 2.5rem; font-weight: 800; margin-bottom: 12px; }
.hero p { font-size: 1.1rem; opacity: 0.9; max-width: 600px; margin: 0 auto 32px; }
.search-bar {
  display: flex;
  max-width: 500px;
  margin: 0 auto;
  border-radius: var(--radius-lg);
  overflow: hidden;
  box-shadow: var(--shadow-lg);
}
.search-bar input {
  flex: 1;
  border: none;
  padding: 16px 20px;
  font-size: 1rem;
  outline: none;
}
.search-bar button {
  background: var(--accent);
  border: none;
  color: var(--white);
  padding: 16px 28px;
  font-weight: 600;
  cursor: pointer;
  transition: background var(--transition);
}
.search-bar button:hover { background: #e55a28; }

/* ─── Coupon Grid ─── */
.section { padding: 40px 0; }
.section-title {
  font-size: 1.5rem;
  font-weight: 700;
  margin-bottom: 24px;
  color: var(--gray-900);
}
.coupon-grid {
  display: grid;
  gap: 16px;
  grid-template-columns: repeat(auto-fill, minmax(300px, 1fr));
}

.coupon-card {
  background: var(--white);
  border-radius: var(--radius-lg);
  box-shadow: var(--shadow);
  padding: 20px;
  transition: box-shadow var(--transition), transform var(--transition);
  display: flex;
  flex-direction: column;
  position: relative;
  border: 1px solid var(--gray-200);
}
.coupon-card:hover {
  box-shadow: var(--shadow-md);
  transform: translateY(-2px);
}
.coupon-store {
  font-size: 0.75rem;
  text-transform: uppercase;
  letter-spacing: 1px;
  color: var(--gray-400);
  margin-bottom: 4px;
}
.coupon-discount {
  font-size: 1.6rem;
  font-weight: 800;
  color: var(--primary);
  margin-bottom: 4px;
}
.coupon-desc {
  color: var(--gray-600);
  font-size: 0.9rem;
  margin-bottom: 12px;
  flex: 1;
}
.coupon-meta {
  display: flex;
  gap: 12px;
  font-size: 0.8rem;
  color: var(--gray-400);
  margin-bottom: 12px;
}
.coupon-code-wrap {
  display: flex;
  align-items: center;
  gap: 8px;
  background: var(--primary-light);
  border: 2px dashed var(--primary);
  border-radius: var(--radius);
  padding: 8px 12px;
  cursor: pointer;
  transition: background var(--transition);
}
.coupon-code-wrap:hover { background: #c8eae8; }
.coupon-code {
  font-family: 'Courier New', monospace;
  font-weight: 700;
  font-size: 1rem;
  color: var(--primary-dark);
  flex: 1;
  letter-spacing: 1px;
}
.copy-btn {
  background: var(--primary);
  color: var(--white);
  border: none;
  border-radius: var(--radius);
  padding: 6px 14px;
  font-size: 0.8rem;
  font-weight: 600;
  cursor: pointer;
  transition: background var(--transition);
}
.copy-btn:hover { background: var(--primary-dark); }
.coupon-expired {
  opacity: 0.5;
  position: relative;
}
.coupon-expired::after {
  content: 'EXPIRED';
  position: absolute;
  top: 12px;
  right: 12px;
  background: var(--gray-400);
  color: var(--white);
  padding: 2px 10px;
  border-radius: 4px;
  font-size: 0.7rem;
  font-weight: 700;
}

.category-filter {
  display: flex;
  gap: 8px;
  flex-wrap: wrap;
  margin-bottom: 24px;
}
.category-filter button {
  padding: 8px 20px;
  border-radius: 20px;
  border: 1px solid var(--gray-200);
  background: var(--white);
  color: var(--gray-600);
  font-size: 0.85rem;
  cursor: pointer;
  transition: all var(--transition);
}
.category-filter button:hover, .category-filter button.active {
  background: var(--primary);
  color: var(--white);
  border-color: var(--primary);
}

/* ─── Submit Page ─── */
.form-card {
  background: var(--white);
  border-radius: var(--radius-lg);
  box-shadow: var(--shadow);
  padding: 32px;
  max-width: 600px;
  margin: 0 auto;
}
.form-card h2 { margin-bottom: 24px; }
.form-group {
  margin-bottom: 16px;
}
.form-group label {
  display: block;
  font-weight: 600;
  font-size: 0.9rem;
  color: var(--gray-700);
  margin-bottom: 6px;
}
.form-group input, .form-group textarea, .form-group select {
  width: 100%;
  padding: 12px 14px;
  border: 1px solid var(--gray-300);
  border-radius: var(--radius);
  font-size: 0.95rem;
  outline: none;
  transition: border var(--transition);
}
.form-group input:focus, .form-group textarea:focus, .form-group select:focus {
  border-color: var(--primary);
  box-shadow: 0 0 0 3px rgba(10,124,122,0.15);
}
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  padding: 12px 28px;
  border: none;
  border-radius: var(--radius);
  font-size: 0.95rem;
  font-weight: 600;
  cursor: pointer;
  transition: all var(--transition);
}
.btn-primary {
  background: var(--primary);
  color: var(--white);
}
.btn-primary:hover { background: var(--primary-dark); }
.btn-accent {
  background: var(--accent);
  color: var(--white);
}
.btn-accent:hover { background: #e55a28; }
.btn-sm {
  padding: 8px 16px;
  font-size: 0.85rem;
}
.btn-block { width: 100%; }
.btn-danger { background: #dc2626; color: var(--white); }
.btn-danger:hover { background: #b91c1c; }
.btn-outline {
  background: transparent;
  border: 1px solid var(--gray-300);
  color: var(--gray-600);
}
.btn-outline:hover { border-color: var(--primary); color: var(--primary); }

.success-message {
  background: #d1fae5;
  color: #065f46;
  padding: 16px;
  border-radius: var(--radius);
  margin-bottom: 16px;
  display: none;
}
.error-message {
  background: #fee2e2;
  color: #991b1b;
  padding: 16px;
  border-radius: var(--radius);
  margin-bottom: 16px;
  display: none;
}

/* ─── Single Coupon ─── */
.coupon-detail {
  background: var(--white);
  border-radius: var(--radius-lg);
  box-shadow: var(--shadow);
  padding: 32px;
  max-width: 700px;
  margin: 0 auto;
}
.coupon-detail .coupon-discount { font-size: 2.5rem; }
.coupon-detail .coupon-code {
  font-size: 1.4rem;
  text-align: center;
  padding: 16px;
}

/* ─── Footer ─── */
.footer {
  background: var(--gray-900);
  color: var(--gray-400);
  padding: 24px 0;
  text-align: center;
  margin-top: auto;
  font-size: 0.85rem;
}

/* ─── Loading ─── */
.loading {
  text-align: center;
  padding: 40px;
  color: var(--gray-400);
}
.spinner {
  width: 32px;
  height: 32px;
  border: 3px solid var(--gray-200);
  border-top-color: var(--primary);
  border-radius: 50%;
  animation: spin 0.8s linear infinite;
  margin: 0 auto 12px;
}
@keyframes spin { to { transform: rotate(360deg); } }

/* ─── Pagination ─── */
.pagination {
  display: flex;
  justify-content: center;
  gap: 8px;
  margin-top: 32px;
}
.pagination button {
  padding: 8px 16px;
  border: 1px solid var(--gray-200);
  border-radius: var(--radius);
  background: var(--white);
  cursor: pointer;
  transition: all var(--transition);
}
.pagination button:hover:not(:disabled) {
  background: var(--primary);
  color: var(--white);
  border-color: var(--primary);
}
.pagination button:disabled { opacity: 0.4; cursor: default; }

/* ─── Toast / notification ─── */
.toast {
  position: fixed;
  bottom: 80px;
  right: 20px;
  background: var(--gray-900);
  color: var(--white);
  padding: 12px 20px;
  border-radius: var(--radius);
  font-size: 0.9rem;
  opacity: 0;
  transform: translateY(10px);
  transition: all 300ms ease;
  pointer-events: none;
  z-index: 200;
}
.toast.show {
  opacity: 1;
  transform: translateY(0);
}

/* ─── Interstitial overlay ─── */
.interstitial-overlay {
  display: none;
  position: fixed;
  inset: 0;
  background: rgba(0,0,0,0.6);
  z-index: 500;
  align-items: center;
  justify-content: center;
}
.interstitial-overlay.show { display: flex; }
.interstitial-box {
  background: var(--white);
  border-radius: var(--radius-lg);
  padding: 32px;
  max-width: 400px;
  width: 90%;
  text-align: center;
  position: relative;
}
.interstitial-close {
  position: absolute;
  top: 8px;
  right: 12px;
  background: none;
  border: none;
  font-size: 1.5rem;
  cursor: pointer;
  color: var(--gray-400);
}

@media (max-width: 768px) {
  .hero h1 { font-size: 1.6rem; }
  .hero p { font-size: 0.95rem; }
  .coupon-grid { grid-template-columns: 1fr; }
  .header-inner { height: 56px; }
  .nav a { padding: 6px 10px; font-size: 0.8rem; }
  .form-card { padding: 20px; }
  .coupon-detail { padding: 20px; }

}