/* Online education website styles */
:root {
  --bg: #0f172a;
  --surface: rgba(15, 23, 42, 0.92);
  --primary: #22d3ee;
  --accent: #fb7185;
  --text: #e2e8f0;
  --muted: #94a3b8;
}

* {
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
}

body {
  margin: 0;
  font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
  background: radial-gradient(circle at top, #1d4ed8 0%, #0f172a 40%, #020617 100%);
  color: var(--text);
}

img {
  max-width: 100%;
}

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

button,
input,
select,textarea {
  font: inherit;
}

.container {
  width: min(1120px, 100% - 2rem);
  margin: 0 auto;
}

header {
  position: sticky;
  top: 0;
  z-index: 10;
  backdrop-filter: blur(16px);
  background: rgba(8, 15, 34, 0.82);
  border-bottom: 1px solid rgba(148, 163, 184, 0.14);
}

.navbar {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1rem;
  padding: 1rem 0;
}

.brand {
  display: inline-flex;
  align-items: center;
  gap: 0.85rem;
  font-size: 1.4rem;
  font-weight: 700;
  letter-spacing: 0.05em;
}

.brand-logo {
  width: 42px;
  height: 42px;
  object-fit: contain;
  border-radius: 50%;
}

.nav-links {
  display: flex;
  gap: 1.25rem;
  flex-wrap: wrap;
}

.nav-links a {
  color: var(--muted);
  transition: color 0.2s ease;
}

.nav-links a:hover {
  color: var(--primary);
}

.hero {
  min-height: 100vh;
  display: grid;
  place-items: center;
  padding: 3rem 0;
  position: relative;
  overflow: hidden;
  background: linear-gradient(180deg, rgba(15, 23, 42, 0.88), rgba(8, 15, 34, 0.95)), url('images/tech-bg.png');
  background-repeat: no-repeat;
  background-size: cover;
  background-position: center center;
}

.hero::before {
  content: '';
  position: absolute;
  inset: 0;
  background: radial-gradient(circle at 20% 20%, rgba(34, 211, 238, 0.18), transparent 18%),
              radial-gradient(circle at 85% 25%, rgba(168, 85, 247, 0.16), transparent 20%),
              radial-gradient(circle at 50% 80%, rgba(14, 165, 233, 0.1), transparent 16%);
  pointer-events: none;
}

.hero-grid {
  display: grid;
  grid-template-columns: minmax(0, 1.2fr) minmax(320px, 1fr);
  gap: 2rem;
  align-items: center;
  position: relative;
  z-index: 1;
}

.hero-content {
  max-width: 620px;
}

.hero-visual {
  display: grid;
  place-items: center;
}

.hero-visual-card {
  position: relative;
  width: 100%;
  max-width: 520px;
  padding: 2rem;
  border-radius: 2rem;
  background: rgba(15, 23, 42, 0.94);
  border: 1px solid rgba(34, 211, 238, 0.18);
  box-shadow: 0 30px 80px rgba(8, 15, 34, 0.25);
  overflow: hidden;
}

.hero-visual-card::before {
  content: '';
  position: absolute;
  inset: 0;
  background: radial-gradient(circle at top left, rgba(34, 211, 238, 0.18), transparent 35%),
              radial-gradient(circle at bottom right, rgba(59, 130, 246, 0.14), transparent 30%);
  pointer-events: none;
}

.hero-visual-card img {
  width: 100%;
  height: auto;
  position: relative;
  z-index: 1;
}

.hero-visual-badge {
  position: absolute;
  top: 1.5rem;
  left: 1.5rem;
  padding: 0.75rem 1.2rem;
  border-radius: 999px;
  font-size: 0.9rem;
  font-weight: 700;
  letter-spacing: 0.02em;
  color: #0f172a;
  background: linear-gradient(135deg, #22d3ee, #a78bfa);
  z-index: 2;
}

.hero-visual-tags {
  display: flex;
  flex-wrap: wrap;
  gap: 0.75rem;
  margin-top: 1.5rem;
  position: relative;
  z-index: 1;
}

.hero-visual-tags span {
  display: inline-flex;
  padding: 0.7rem 1rem;
  background: rgba(255, 255, 255, 0.08);
  border: 1px solid rgba(255, 255, 255, 0.1);
  border-radius: 999px;
  color: #cbd5e1;
  font-size: 0.9rem;
}

@media (max-width: 900px) {
  .hero-grid {
    grid-template-columns: 1fr;
  }

  .hero {
    min-height: auto;
    padding-top: 4rem;
    padding-bottom: 4rem;
  }
}

.hero h1 {
  font-size: clamp(2.7rem, 4vw, 4.2rem);
  line-height: 1.05;
  margin: 0;
}

.hero p {
  margin: 1.5rem 0;
  max-width: 44rem;
  line-height: 1.8;
  color: var(--muted);
}

.cta-group {
  display: flex;
  flex-wrap: wrap;
  gap: 1rem;
}

.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  padding: 0.95rem 1.8rem;
  border-radius: 999px;
  border: none;
  cursor: pointer;
  font-weight: 600;
  transition: transform 0.2s ease, filter 0.2s ease;
}

.btn-primary {
  background: linear-gradient(135deg, #22d3ee, #818cf8);
  color: #0f172a;
}

.btn-secondary {
  background: rgba(148, 163, 184, 0.18);
  color: var(--text);
}

.btn:hover {
  transform: translateY(-2px);
}

.stats {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(160px, 1fr));
  gap: 1rem;
  margin-top: 2.5rem;
}

.stat-card {
  background: rgba(15, 23, 42, 0.85);
  border: 1px solid rgba(148, 163, 184, 0.16);
  padding: 1.35rem;
  border-radius: 1.25rem;
}

.stat-card h2 {
  margin: 0;
  font-size: 1.75rem;
}

.section {
  padding: 4rem 0;
}

.section-title {
  display: flex;
  align-items: center;
  gap: 0.75rem;
  margin-bottom: 2rem;
}

.section-title h2 {
  margin: 0;
  font-size: 2rem;
}

.cards {
  display: grid;
  gap: 1.5rem;
  grid-template-columns: repeat(auto-fit, minmax(240px, 1fr));
}

.card {
  position: relative;
  overflow: hidden;
  background: linear-gradient(135deg, rgba(15, 23, 42, 0.96), rgba(15, 23, 42, 0.84));
  border: 1px solid rgba(148, 163, 184, 0.14);
  padding: 1.75rem;
  border-radius: 1.5rem;
  transition: transform 0.2s ease, border-color 0.2s ease;
}

.card::before {
  content: '';
  position: absolute;
  inset: 0;
  background: radial-gradient(circle at top left, rgba(34, 211, 238, 0.12), transparent 25%),
              radial-gradient(circle at bottom right, rgba(167, 139, 250, 0.12), transparent 25%);
  pointer-events: none;
}

.card:hover {
  transform: translateY(-6px);
  border-color: rgba(34, 211, 238, 0.35);
}

.card h3 {
  margin-top: 0;
  position: relative;
  z-index: 1;
}

.card p {
  color: var(--muted);
  line-height: 1.75;
  position: relative;
  z-index: 1;
}

.card::after {
  content: '';
  position: absolute;
  width: 160px;
  height: 160px;
  border-radius: 50%;
  background: rgba(34, 211, 238, 0.08);
  top: -40px;
  right: -40px;
  filter: blur(12px);
  pointer-events: none;
}

.card-feature {
  background: linear-gradient(135deg, rgba(59, 130, 246, 0.18), rgba(14, 165, 233, 0.14));
  border-color: rgba(34, 211, 238, 0.28);
}

.card-feature::before,
.card-feature::after {
  background: none;
}

.card-feature::after {
  background: rgba(59, 130, 246, 0.14);
}

.course-image {
  position: relative;
  width: 100%;
  border-radius: 1.25rem;
  overflow: hidden;
  margin-bottom: 1.4rem;
  min-height: 160px;
  background: rgba(15, 23, 42, 0.95);
  display: grid;
  place-items: center;
}

.course-image img {
  width: 100%;
  height: 100%;
  object-fit: cover;
}

.course-footer {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1rem;
  margin-top: 1.4rem;
}

.course-price {
  font-weight: 700;
  font-size: 1rem;
  color: #fff;
}

.cart-empty,
.cart-items,
.cart-summary,
.payment-card {
  width: 100%;
}

.cart-empty {
  padding: 1.5rem;
  background: rgba(15, 23, 42, 0.9);
  border: 1px dashed rgba(148, 163, 184, 0.4);
  color: var(--muted);
  border-radius: 1rem;
  text-align: center;
}

.cart-item {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1rem;
  padding: 1rem;
  background: rgba(8, 15, 34, 0.96);
  border: 1px solid rgba(148, 163, 184, 0.12);
  border-radius: 1rem;
  margin-bottom: 0.85rem;
}

.cart-item strong {
  color: var(--text);
}

.cart-item .remove-btn {
  background: rgba(248, 113, 113, 0.14);
  color: #fecaca;
}

.cart-summary {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1rem;
  padding: 1.25rem;
  background: rgba(8, 15, 34, 0.96);
  border: 1px solid rgba(148, 163, 184, 0.14);
  border-radius: 1.25rem;
  margin-top: 1rem;
}

.payment-card {
  margin-top: 1.5rem;
  padding: 1.5rem;
  background: rgba(8, 15, 34, 0.95);
  border: 1px solid rgba(148, 163, 184, 0.14);
  border-radius: 1.5rem;
}

.payment-row {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 1rem;
}

.payment-row input {
  width: 100%;
}

@media (max-width: 760px) {
  .payment-row {
    grid-template-columns: 1fr;
  }
}

.course-list {
  margin-top: 1rem;
  list-style: none;
  padding: 0;
  display: grid;
  gap: 0.75rem;
}

.course-list li {
  display: flex;
  gap: 0.75rem;
  align-items: center;
  color: var(--muted);
}

.course-list li::before {
  content: '✓';
  color: var(--primary);
  font-weight: 700;
}

.form-grid {
  display: grid;
  gap: 1.25rem;
  grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
}

.form-card {
  background: rgba(8, 15, 34, 0.9);
  padding: 2rem;
  border-radius: 1.5rem;
  border: 1px solid rgba(148, 163, 184, 0.12);
}

.form-card label {
  display: block;
  margin-bottom: 0.5rem;
  color: var(--muted);
  font-size: 0.95rem;
}

.form-card input,
.form-card select,
.form-card textarea {
  width: 100%;
  background: rgba(15, 23, 42, 0.96);
  border: 1px solid rgba(148, 163, 184, 0.18);
  border-radius: 0.95rem;
  padding: 0.95rem 1rem;
  color: var(--text);
}

.form-card textarea {
  min-height: 140px;
  resize: vertical;
}

.form-card input:focus,
.form-card select:focus,
.form-card textarea:focus {
  outline: none;
  border-color: var(--primary);
  box-shadow: 0 0 0 3px rgba(34, 211, 238, 0.16);
}

.form-card .submit-row {
  display: flex;
  justify-content: flex-end;
}

.message-box {
  background: rgba(34, 211, 238, 0.12);
  border: 1px solid rgba(34, 211, 238, 0.28);
  color: #d1fae5;
  padding: 1rem 1.2rem;
  border-radius: 1rem;
  margin-top: 1rem;
  display: none;
}

.admin-table {
  width: 100%;
  border-collapse: collapse;
  font-size: 0.95rem;
  min-width: 680px;
}

.admin-table th,
.admin-table td {
  padding: 0.95rem 0.8rem;
  border: 1px solid rgba(148, 163, 184, 0.16);
  text-align: left;
}

.admin-table thead {
  background: rgba(15, 23, 42, 0.94);
}

.admin-table th {
  color: var(--text);
  font-weight: 600;
}

.admin-table tbody tr {
  background: rgba(8, 15, 34, 0.9);
}

.admin-table tbody tr:nth-child(even) {
  background: rgba(15, 23, 42, 0.86);
}

.btn-small {
  padding: 0.55rem 0.8rem;
  border-radius: 0.95rem;
  font-size: 0.85rem;
}

.btn-small + .btn-small {
  margin-left: 0.5rem;
}

footer {
  padding: 2rem 0;
  text-align: center;
  color: var(--muted);
  border-top: 1px solid rgba(148, 163, 184, 0.12);
}

@media (min-width: 900px) {
  .hero-grid {
    grid-template-columns: 1.05fr 0.95fr;
    align-items: center;
  }
}

@media (max-width: 720px) {
  .navbar {
    flex-direction: column;
    align-items: start;
  }
}