/* ===== CSS Variables ===== */
:root {
  --primary: #1a5276;
  --primary-light: #2980b9;
  --secondary: #2d6a4f;
  --secondary-light: #40916c;
  --accent: #e76f51;
  --accent-hover: #d4603f;
  --bg: #f8f6f2;
  --bg-alt: #f0ece4;
  --bg-card: #ffffff;
  --text: #1a1a1a;
  --text-secondary: #555555;
  --text-muted: #888888;
  --border: #e0dcd4;
  --shadow: 0 2px 12px rgba(0,0,0,0.08);
  --shadow-hover: 0 8px 30px rgba(0,0,0,0.12);
  --radius: 12px;
  --radius-sm: 8px;
  --radius-lg: 20px;
  --nav-height: 64px;
  --transition: 0.3s ease;
  --gradient-primary: linear-gradient(135deg, #1a5276 0%, #2d6a4f 100%);
  --gradient-accent: linear-gradient(135deg, #e76f51 0%, #f4a261 100%);
  --gradient-color: linear-gradient(135deg, #667eea 0%, #764ba2 25%, #f093fb 50%, #f5576c 75%, #fda085 100%);
}

[data-theme="dark"] {
  --primary: #3498db;
  --primary-light: #5dade2;
  --secondary: #52b788;
  --secondary-light: #74c69d;
  --accent: #f4a261;
  --accent-hover: #f4845f;
  --bg: #0d1b2a;
  --bg-alt: #1b2838;
  --bg-card: #162335;
  --text: #e0e0e0;
  --text-secondary: #b0b0b0;
  --text-muted: #777777;
  --border: #2a3a4a;
  --shadow: 0 2px 12px rgba(0,0,0,0.3);
  --shadow-hover: 0 8px 30px rgba(0,0,0,0.4);
}

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

html {
  scroll-behavior: smooth;
}

body {
  font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', 'PingFang SC', 'Hiragino Sans GB', 'Microsoft YaHei', sans-serif;
  background: var(--bg);
  color: var(--text);
  line-height: 1.6;
  transition: background var(--transition), color var(--transition);
}

a {
  color: var(--primary);
  text-decoration: none;
  transition: color var(--transition);
}

a:hover { color: var(--primary-light); }

img {
  max-width: 100%;
  height: auto;
  display: block;
}

/* ===== Typography ===== */
h1, h2, h3, h4, h5, h6 {
  line-height: 1.3;
  font-weight: 700;
}

h1 { font-size: clamp(2rem, 5vw, 3.5rem); }
h2 { font-size: clamp(1.5rem, 4vw, 2.5rem); }
h3 { font-size: clamp(1.2rem, 3vw, 1.75rem); }

.section-title {
  text-align: center;
  margin-bottom: 1rem;
  color: var(--primary);
}

.section-subtitle {
  text-align: center;
  color: var(--text-secondary);
  margin-bottom: 3rem;
  font-size: 1.1rem;
}

/* ===== Container ===== */
.container {
  width: 100%;
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 1.5rem;
}

/* ===== Buttons ===== */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 0.5rem;
  padding: 0.75rem 1.75rem;
  border: none;
  border-radius: var(--radius-sm);
  font-size: 1rem;
  font-weight: 600;
  cursor: pointer;
  transition: all var(--transition);
  text-decoration: none;
}

.btn-primary {
  background: var(--gradient-accent);
  color: #fff;
}

.btn-primary:hover {
  transform: translateY(-2px);
  box-shadow: 0 6px 20px rgba(231, 111, 81, 0.4);
  color: #fff;
}

.btn-outline {
  background: transparent;
  color: var(--text);
  border: 2px solid var(--border);
}

.btn-outline:hover {
  border-color: var(--primary);
  color: var(--primary);
  transform: translateY(-2px);
}

/* ===== Cards ===== */
.card {
  background: var(--bg-card);
  border-radius: var(--radius);
  box-shadow: var(--shadow);
  overflow: hidden;
  transition: all var(--transition);
}

.card:hover {
  box-shadow: var(--shadow-hover);
  transform: translateY(-4px);
}

.card-img {
  width: 100%;
  aspect-ratio: 4/3;
  object-fit: cover;
  background: var(--bg-alt);
}

.card-body {
  padding: 1.25rem;
}

.card-title {
  font-size: 1.1rem;
  font-weight: 600;
  margin-bottom: 0.5rem;
  color: var(--text);
}

.card-desc {
  font-size: 0.9rem;
  color: var(--text-secondary);
  margin-bottom: 0.75rem;
}

.card-link {
  font-size: 0.9rem;
  font-weight: 600;
  color: var(--accent);
}

.card-link:hover { color: var(--accent-hover); }

/* ===== Placeholder Image ===== */
.placeholder-img {
  width: 100%;
  aspect-ratio: 4/3;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 0.9rem;
  color: rgba(255,255,255,0.8);
  font-weight: 600;
  background: var(--gradient-primary);
  position: relative;
  overflow: hidden;
}

.placeholder-img::after {
  content: '';
  position: absolute;
  inset: 0;
  background: linear-gradient(45deg, transparent 30%, rgba(255,255,255,0.1) 50%, transparent 70%);
  animation: shimmer 3s infinite;
}

@keyframes shimmer {
  0% { transform: translateX(-100%); }
  100% { transform: translateX(100%); }
}

.placeholder-img.p1 { background: linear-gradient(135deg, #1a5276, #2980b9); }
.placeholder-img.p2 { background: linear-gradient(135deg, #2d6a4f, #40916c); }
.placeholder-img.p3 { background: linear-gradient(135deg, #e76f51, #f4a261); }
.placeholder-img.p4 { background: linear-gradient(135deg, #6c5ce7, #a29bfe); }
.placeholder-img.p5 { background: linear-gradient(135deg, #00b894, #55efc4); }
.placeholder-img.p6 { background: linear-gradient(135deg, #fdcb6e, #e17055); }
.placeholder-img.p7 { background: linear-gradient(135deg, #74b9ff, #0984e3); }

/* ===== Grid ===== */
.grid {
  display: grid;
  gap: 1.5rem;
}

.grid-2 { grid-template-columns: repeat(auto-fit, minmax(280px, 1fr)); }
.grid-3 { grid-template-columns: repeat(auto-fit, minmax(260px, 1fr)); }
.grid-4 { grid-template-columns: repeat(auto-fit, minmax(220px, 1fr)); }

/* ===== Section Spacing ===== */
section {
  padding: 4rem 0;
}

/* ===== Navigation ===== */
.nav {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  height: var(--nav-height);
  z-index: 1000;
  background: rgba(248, 246, 242, 0.85);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--border);
  transition: background var(--transition);
}

[data-theme="dark"] .nav {
  background: rgba(13, 27, 42, 0.85);
}

.nav-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 100%;
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 1.5rem;
}

.nav-brand {
  display: inline-flex;
  align-items: center;
  gap: 0.15em;
  font-size: 1.3rem;
  font-weight: 800;
  color: var(--primary);
  white-space: nowrap;
}

.nav-brand:hover { color: var(--primary-light); }

.nav-logo {
  height: 1.4em;
  width: auto;
  vertical-align: middle;
  margin-right: 0.1em;
}

.nav-links {
  display: flex;
  align-items: center;
  gap: 0.25rem;
  list-style: none;
}

.nav-links a {
  padding: 0.5rem 0.75rem;
  border-radius: var(--radius-sm);
  font-size: 0.9rem;
  font-weight: 500;
  color: var(--text-secondary);
  transition: all var(--transition);
}

.nav-links a:hover,
.nav-links a.active {
  color: var(--primary);
  background: var(--bg-alt);
}

.nav-actions {
  display: flex;
  align-items: center;
  gap: 0.5rem;
}

.nav-btn {
  background: none;
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
  padding: 0.4rem 0.6rem;
  cursor: pointer;
  font-size: 0.85rem;
  color: var(--text-secondary);
  transition: all var(--transition);
  display: flex;
  align-items: center;
  gap: 0.3rem;
}

.nav-btn:hover {
  border-color: var(--primary);
  color: var(--primary);
}

/* Hamburger */
.nav-hamburger {
  display: none;
  flex-direction: column;
  gap: 5px;
  cursor: pointer;
  padding: 0.5rem;
  background: none;
  border: none;
}

.nav-hamburger span {
  display: block;
  width: 24px;
  height: 2px;
  background: var(--text);
  transition: all var(--transition);
  border-radius: 2px;
}

@media (max-width: 768px) {
  .nav-hamburger { display: flex; }

  .nav-links {
    position: fixed;
    top: var(--nav-height);
    left: 0;
    right: 0;
    background: var(--bg);
    flex-direction: column;
    padding: 1rem;
    gap: 0.25rem;
    border-bottom: 1px solid var(--border);
    transform: translateY(-120%);
    opacity: 0;
    transition: all var(--transition);
    z-index: 999;
  }

  .nav-links.open {
    transform: translateY(0);
    opacity: 1;
  }

  .nav-links a {
    padding: 0.75rem 1rem;
    font-size: 1rem;
  }
}

/* ===== Footer ===== */
.footer {
  background: var(--bg-alt);
  border-top: 1px solid var(--border);
  padding: 3rem 0 1.5rem;
}

.footer-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
  gap: 2rem;
  margin-bottom: 2rem;
}

.footer-brand {
  font-size: 1.2rem;
  font-weight: 800;
  color: var(--primary);
  margin-bottom: 0.5rem;
}

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

.footer-title {
  font-weight: 700;
  margin-bottom: 1rem;
  color: var(--text);
}

.footer-links {
  list-style: none;
  display: flex;
  flex-direction: column;
  gap: 0.5rem;
}

.footer-links a {
  color: var(--text-secondary);
  font-size: 0.9rem;
}

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

.footer-bottom {
  text-align: center;
  padding-top: 1.5rem;
  border-top: 1px solid var(--border);
  font-size: 0.85rem;
  color: var(--text-muted);
}

/* ===== Badge ===== */
.badge {
  display: inline-block;
  padding: 0.25rem 0.75rem;
  border-radius: 20px;
  font-size: 0.75rem;
  font-weight: 600;
}

.badge-accent {
  background: var(--accent);
  color: #fff;
}

.badge-outline {
  background: transparent;
  border: 1px solid var(--accent);
  color: var(--accent);
}

/* ===== Page Header ===== */
.page-header {
  padding: calc(var(--nav-height) + 3rem) 0 2rem;
  text-align: center;
}

/* ===== Filter Bar ===== */
.filter-bar {
  margin-bottom: 2rem;
}

.filter-group {
  display: flex;
  flex-wrap: wrap;
  gap: 0.5rem;
  margin-bottom: 1rem;
}

.filter-btn {
  padding: 0.5rem 1rem;
  border: 1px solid var(--border);
  border-radius: 20px;
  background: var(--bg-card);
  color: var(--text-secondary);
  font-size: 0.85rem;
  cursor: pointer;
  transition: all var(--transition);
}

.filter-btn:hover {
  border-color: var(--primary);
  color: var(--primary);
}

.filter-btn.active {
  background: var(--primary);
  border-color: var(--primary);
  color: #fff;
}

/* ===== Modal ===== */
.modal-overlay {
  position: fixed;
  inset: 0;
  background: rgba(0,0,0,0.5);
  z-index: 2000;
  display: flex;
  align-items: center;
  justify-content: center;
  padding: 1rem;
  opacity: 0;
  visibility: hidden;
  transition: all var(--transition);
}

.modal-overlay.active {
  opacity: 1;
  visibility: visible;
}

.modal {
  background: var(--bg-card);
  border-radius: var(--radius-lg);
  max-width: 600px;
  width: 100%;
  max-height: 90vh;
  overflow-y: auto;
  transform: scale(0.9);
  transition: transform var(--transition);
}

.modal-overlay.active .modal {
  transform: scale(1);
}

.modal-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 1.25rem 1.5rem;
  border-bottom: 1px solid var(--border);
}

.modal-close {
  background: none;
  border: none;
  font-size: 1.5rem;
  cursor: pointer;
  color: var(--text-muted);
  padding: 0.25rem;
}

.modal-body { padding: 1.5rem; }

/* ===== Animations ===== */
@keyframes fadeInUp {
  from { opacity: 0; transform: translateY(20px); }
  to { opacity: 1; transform: translateY(0); }
}

.animate-in {
  animation: fadeInUp 0.6s ease forwards;
}

/* ===== Utility ===== */
.text-center { text-align: center; }
.mt-1 { margin-top: 0.5rem; }
.mt-2 { margin-top: 1rem; }
.mt-3 { margin-top: 1.5rem; }
.mb-1 { margin-bottom: 0.5rem; }
.mb-2 { margin-bottom: 1rem; }
.mb-3 { margin-bottom: 1.5rem; }
.gap-1 { gap: 0.5rem; }
.flex { display: flex; }
.flex-wrap { flex-wrap: wrap; }
.items-center { align-items: center; }
.justify-center { justify-content: center; }