:root {
  --bg-primary: #ffffff;
  --bg-secondary: #f7f8fa;
  --bg-card: #ffffff;
  --bg-hover: #f0f2f5;
  --bg-modal: rgba(0, 0, 0, 0.5);
  --text-primary: #1a1a1a;
  --text-secondary: #646a73;
  --text-muted: #8f959e;
  --border-color: #e5e6eb;
  --accent-color: #ff4d4f;
  --accent-hover: #ff7875;
  --accent-light: #fff1f0;
  --hot-color: #fa541c;
  --category-tech: #1890ff;
  --category-finance: #52c41a;
  --category-sports: #fa8c16;
  --category-entertainment: #eb2f96;
  --category-international: #722ed1;
  --category-society: #13c2c2;
  --category-game: #f5222d;
  --category-auto: #2f54eb;
  --shadow-sm: 0 1px 2px rgba(0, 0, 0, 0.06);
  --shadow-md: 0 4px 12px rgba(0, 0, 0, 0.08);
  --shadow-lg: 0 8px 24px rgba(0, 0, 0, 0.12);
  --radius-sm: 6px;
  --radius-md: 10px;
  --radius-lg: 16px;
  --header-height: 64px;
  --transition: 0.25s cubic-bezier(0.4, 0, 0.2, 1);
}

[data-theme="dark"] {
  --bg-primary: #141414;
  --bg-secondary: #1f1f1f;
  --bg-card: #262626;
  --bg-hover: #333333;
  --bg-modal: rgba(0, 0, 0, 0.7);
  --text-primary: #f0f0f0;
  --text-secondary: #bfbfbf;
  --text-muted: #8c8c8c;
  --border-color: #434343;
  --accent-color: #ff7875;
  --accent-hover: #ffa39e;
  --accent-light: #2a1215;
  --hot-color: #ff7a45;
  --category-tech: #40a9ff;
  --category-finance: #73d13d;
  --category-sports: #ffa940;
  --category-entertainment: #f759ab;
  --category-international: #9254de;
  --category-society: #36cfc9;
  --category-game: #ff4d4f;
  --category-auto: #597ef7;
  --shadow-sm: 0 1px 2px rgba(0, 0, 0, 0.3);
  --shadow-md: 0 4px 12px rgba(0, 0, 0, 0.4);
  --shadow-lg: 0 8px 24px rgba(0, 0, 0, 0.5);
}

* {
  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-color: var(--bg-secondary);
  color: var(--text-primary);
  line-height: 1.6;
  transition: background-color var(--transition), color var(--transition);
  min-height: 100vh;
  display: flex;
  flex-direction: column;
}

.container {
  width: 100%;
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 20px;
}

.hidden {
  display: none !important;
}

.site-header {
  position: sticky;
  top: 0;
  z-index: 100;
  background-color: var(--bg-primary);
  border-bottom: 1px solid var(--border-color);
  height: var(--header-height);
  transition: background-color var(--transition), border-color var(--transition);
  backdrop-filter: blur(8px);
}

.header-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 100%;
}

.logo-wrap {
  display: flex;
  align-items: center;
  gap: 10px;
}

.logo-icon {
  font-size: 28px;
  animation: pulse 2s infinite;
}

@keyframes pulse {
  0%, 100% { transform: scale(1); }
  50% { transform: scale(1.1); }
}

.logo-text {
  font-size: 22px;
  font-weight: 700;
  background: linear-gradient(135deg, var(--accent-color), var(--hot-color));
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

.header-actions {
  display: flex;
  align-items: center;
  gap: 12px;
}

.theme-toggle {
  width: 42px;
  height: 42px;
  border-radius: 50%;
  border: 1px solid var(--border-color);
  background-color: var(--bg-card);
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 18px;
  transition: all var(--transition);
}

.theme-toggle:hover {
  background-color: var(--bg-hover);
  transform: rotate(15deg);
}

.theme-icon {
  transition: opacity var(--transition), transform var(--transition);
}

[data-theme="light"] .theme-icon.moon,
[data-theme="dark"] .theme-icon.sun {
  display: none;
}

.main-content {
  flex: 1;
  padding: 24px 0;
}

.search-section {
  margin-bottom: 24px;
}

.search-box {
  position: relative;
  max-width: 640px;
  margin: 0 auto;
}

.search-input {
  width: 100%;
  height: 52px;
  padding: 0 56px 0 24px;
  font-size: 16px;
  border: 2px solid var(--border-color);
  border-radius: var(--radius-lg);
  background-color: var(--bg-card);
  color: var(--text-primary);
  outline: none;
  transition: all var(--transition);
}

.search-input:focus {
  border-color: var(--accent-color);
  box-shadow: 0 0 0 4px var(--accent-light);
}

.search-input::placeholder {
  color: var(--text-muted);
}

.search-icon {
  position: absolute;
  right: 20px;
  top: 50%;
  transform: translateY(-50%);
  font-size: 20px;
  color: var(--text-muted);
  pointer-events: none;
}

.filter-section {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
  margin-bottom: 24px;
  flex-wrap: wrap;
}

.category-tabs {
  display: flex;
  gap: 8px;
  flex-wrap: wrap;
  flex: 1;
}

.category-tab {
  padding: 8px 18px;
  border: 1px solid var(--border-color);
  border-radius: 20px;
  background-color: var(--bg-card);
  color: var(--text-secondary);
  font-size: 14px;
  cursor: pointer;
  transition: all var(--transition);
  white-space: nowrap;
}

.category-tab:hover {
  background-color: var(--bg-hover);
  color: var(--text-primary);
}

.category-tab.active {
  background-color: var(--accent-color);
  color: #ffffff;
  border-color: var(--accent-color);
}

.sort-group {
  display: flex;
  align-items: center;
  gap: 8px;
}

.sort-label {
  font-size: 14px;
  color: var(--text-secondary);
}

.sort-select {
  padding: 8px 14px;
  border: 1px solid var(--border-color);
  border-radius: var(--radius-sm);
  background-color: var(--bg-card);
  color: var(--text-primary);
  font-size: 14px;
  cursor: pointer;
  outline: none;
  transition: all var(--transition);
}

.sort-select:focus {
  border-color: var(--accent-color);
}

.state-box {
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  padding: 80px 20px;
  text-align: center;
  background-color: var(--bg-card);
  border-radius: var(--radius-md);
  border: 1px solid var(--border-color);
}

.state-box.loading p,
.state-box.empty p,
.state-box.error p {
  color: var(--text-secondary);
  margin-top: 12px;
}

.state-box h3 {
  margin-top: 16px;
  font-size: 18px;
}

.spinner {
  width: 48px;
  height: 48px;
  border: 4px solid var(--border-color);
  border-top-color: var(--accent-color);
  border-radius: 50%;
  animation: spin 0.8s linear infinite;
}

@keyframes spin {
  to { transform: rotate(360deg); }
}

.empty-icon,
.error-icon {
  font-size: 56px;
}

.btn-primary {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  padding: 10px 24px;
  background-color: var(--accent-color);
  color: #ffffff;
  border: none;
  border-radius: var(--radius-sm);
  font-size: 14px;
  font-weight: 500;
  cursor: pointer;
  text-decoration: none;
  transition: all var(--transition);
  margin-top: 20px;
}

.btn-primary:hover {
  background-color: var(--accent-hover);
  transform: translateY(-1px);
  box-shadow: var(--shadow-md);
}

.news-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(300px, 1fr));
  gap: 20px;
}

.news-card {
  background-color: var(--bg-card);
  border-radius: var(--radius-md);
  overflow: hidden;
  cursor: pointer;
  transition: all var(--transition);
  border: 1px solid var(--border-color);
  display: flex;
  flex-direction: column;
}

.news-card:hover {
  transform: translateY(-4px);
  box-shadow: var(--shadow-lg);
  border-color: transparent;
}

.card-cover {
  width: 100%;
  aspect-ratio: 16 / 9;
  object-fit: cover;
  background-color: var(--bg-hover);
}

.card-body {
  padding: 16px;
  flex: 1;
  display: flex;
  flex-direction: column;
}

.card-title {
  font-size: 16px;
  font-weight: 600;
  line-height: 1.5;
  color: var(--text-primary);
  margin-bottom: 8px;
  display: -webkit-box;
  -webkit-line-clamp: 2;
  -webkit-box-orient: vertical;
  overflow: hidden;
}

.card-summary {
  font-size: 14px;
  color: var(--text-secondary);
  line-height: 1.6;
  margin-bottom: 16px;
  display: -webkit-box;
  -webkit-line-clamp: 2;
  -webkit-box-orient: vertical;
  overflow: hidden;
  flex: 1;
}

.card-footer {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 8px;
  padding-top: 12px;
  border-top: 1px solid var(--border-color);
}

.card-meta {
  display: flex;
  align-items: center;
  gap: 8px;
  font-size: 12px;
  color: var(--text-muted);
  flex-wrap: wrap;
}

.card-source {
  font-weight: 500;
  color: var(--text-secondary);
}

.card-tags {
  display: flex;
  gap: 6px;
  align-items: center;
}

.hot-tag {
  display: inline-flex;
  align-items: center;
  gap: 3px;
  padding: 2px 8px;
  background-color: var(--accent-light);
  color: var(--hot-color);
  border-radius: 10px;
  font-size: 12px;
  font-weight: 500;
}

.hot-tag::before {
  content: "🔥";
  font-size: 11px;
}

.category-tag {
  display: inline-flex;
  padding: 2px 8px;
  border-radius: 10px;
  font-size: 12px;
  font-weight: 500;
  color: #ffffff;
}

.category-tag.tech { background-color: var(--category-tech); }
.category-tag.finance { background-color: var(--category-finance); }
.category-tag.sports { background-color: var(--category-sports); }
.category-tag.entertainment { background-color: var(--category-entertainment); }
.category-tag.international { background-color: var(--category-international); }
.category-tag.society { background-color: var(--category-society); }
.category-tag.game { background-color: var(--category-game); }
.category-tag.auto { background-color: var(--category-auto); }

.result-info {
  margin-top: 24px;
  text-align: center;
  color: var(--text-muted);
  font-size: 14px;
  padding: 12px;
}

.modal {
  position: fixed;
  inset: 0;
  z-index: 1000;
  display: flex;
  align-items: center;
  justify-content: center;
  padding: 20px;
}

.modal-overlay {
  position: absolute;
  inset: 0;
  background-color: var(--bg-modal);
  backdrop-filter: blur(4px);
  animation: fadeIn 0.2s ease;
}

@keyframes fadeIn {
  from { opacity: 0; }
  to { opacity: 1; }
}

.modal-content {
  position: relative;
  background-color: var(--bg-card);
  border-radius: var(--radius-lg);
  max-width: 800px;
  width: 100%;
  max-height: 90vh;
  overflow: hidden;
  box-shadow: var(--shadow-lg);
  animation: slideUp 0.3s ease;
}

@keyframes slideUp {
  from {
    opacity: 0;
    transform: translateY(20px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

.modal-close {
  position: absolute;
  top: 16px;
  right: 16px;
  width: 36px;
  height: 36px;
  border-radius: 50%;
  border: none;
  background-color: var(--bg-hover);
  color: var(--text-primary);
  font-size: 24px;
  cursor: pointer;
  z-index: 10;
  display: flex;
  align-items: center;
  justify-content: center;
  transition: all var(--transition);
  line-height: 1;
}

.modal-close:hover {
  background-color: var(--accent-color);
  color: #ffffff;
  transform: rotate(90deg);
}

.modal-body {
  padding: 32px;
  overflow-y: auto;
  max-height: 90vh;
}

.modal-title {
  font-size: 24px;
  font-weight: 700;
  line-height: 1.4;
  margin-bottom: 16px;
  padding-right: 40px;
  color: var(--text-primary);
}

.modal-meta {
  display: flex;
  align-items: center;
  gap: 8px;
  flex-wrap: wrap;
  margin-bottom: 20px;
  font-size: 14px;
  color: var(--text-muted);
}

.modal-source {
  font-weight: 500;
  color: var(--text-secondary);
}

.modal-dot {
  color: var(--text-muted);
}

.modal-date {
  color: var(--text-muted);
}

.modal-category {
  display: inline-flex;
  padding: 2px 10px;
  border-radius: 10px;
  font-size: 12px;
  font-weight: 500;
  color: #ffffff;
}

.modal-category.tech { background-color: var(--category-tech); }
.modal-category.finance { background-color: var(--category-finance); }
.modal-category.sports { background-color: var(--category-sports); }
.modal-category.entertainment { background-color: var(--category-entertainment); }
.modal-category.international { background-color: var(--category-international); }
.modal-category.society { background-color: var(--category-society); }
.modal-category.game { background-color: var(--category-game); }
.modal-category.auto { background-color: var(--category-auto); }

.modal-hot {
  display: inline-flex;
  align-items: center;
  gap: 3px;
  padding: 2px 10px;
  background-color: var(--accent-light);
  color: var(--hot-color);
  border-radius: 10px;
  font-size: 12px;
  font-weight: 500;
}

.modal-hot::before {
  content: "🔥";
  font-size: 11px;
}

.modal-cover {
  width: 100%;
  max-height: 400px;
  object-fit: cover;
  border-radius: var(--radius-md);
  margin-bottom: 20px;
}

.modal-content-text {
  font-size: 16px;
  line-height: 1.8;
  color: var(--text-primary);
}

.modal-content-text p {
  margin-bottom: 16px;
}

.modal-footer {
  margin-top: 24px;
  padding-top: 20px;
  border-top: 1px solid var(--border-color);
  display: flex;
  justify-content: flex-end;
}

.modal-footer .btn-primary {
  margin-top: 0;
}

.back-to-top {
  position: fixed;
  bottom: 32px;
  right: 32px;
  width: 48px;
  height: 48px;
  border-radius: 50%;
  border: none;
  background-color: var(--accent-color);
  color: #ffffff;
  font-size: 22px;
  font-weight: bold;
  cursor: pointer;
  box-shadow: var(--shadow-md);
  z-index: 99;
  display: flex;
  align-items: center;
  justify-content: center;
  transition: all var(--transition);
  opacity: 0;
  visibility: hidden;
  transform: translateY(10px);
}

.back-to-top:not(.hidden) {
  opacity: 1;
  visibility: visible;
  transform: translateY(0);
}

.back-to-top:hover {
  background-color: var(--accent-hover);
  transform: translateY(-4px);
  box-shadow: var(--shadow-lg);
}

.site-footer {
  background-color: var(--bg-primary);
  border-top: 1px solid var(--border-color);
  padding: 24px 0;
  margin-top: 40px;
  transition: background-color var(--transition), border-color var(--transition);
}

.site-footer p {
  text-align: center;
  color: var(--text-muted);
  font-size: 14px;
}

@media (max-width: 768px) {
  .container {
    padding: 0 16px;
  }

  :root {
    --header-height: 56px;
  }

  .logo-text {
    font-size: 18px;
  }

  .logo-icon {
    font-size: 24px;
  }

  .search-input {
    height: 46px;
    font-size: 15px;
  }

  .filter-section {
    gap: 12px;
  }

  .category-tabs {
    gap: 6px;
  }

  .category-tab {
    padding: 6px 14px;
    font-size: 13px;
  }

  .news-grid {
    grid-template-columns: repeat(auto-fill, minmax(260px, 1fr));
    gap: 16px;
  }

  .card-title {
    font-size: 15px;
  }

  .card-summary {
    font-size: 13px;
  }

  .modal-body {
    padding: 20px;
  }

  .modal-title {
    font-size: 20px;
    padding-right: 36px;
  }

  .modal-close {
    top: 12px;
    right: 12px;
    width: 32px;
    height: 32px;
    font-size: 20px;
  }

  .back-to-top {
    bottom: 20px;
    right: 20px;
    width: 42px;
    height: 42px;
    font-size: 18px;
  }
}

@media (max-width: 480px) {
  .container {
    padding: 0 12px;
  }

  .header-inner {
    gap: 8px;
  }

  .logo-text {
    font-size: 16px;
  }

  .search-input {
    height: 44px;
    padding: 0 48px 0 16px;
    font-size: 14px;
  }

  .search-icon {
    right: 16px;
    font-size: 18px;
  }

  .category-tabs {
    width: 100%;
    overflow-x: auto;
    flex-wrap: nowrap;
    padding-bottom: 4px;
    -webkit-overflow-scrolling: touch;
    scrollbar-width: none;
  }

  .category-tabs::-webkit-scrollbar {
    display: none;
  }

  .category-tab {
    flex-shrink: 0;
  }

  .sort-group {
    width: 100%;
    justify-content: flex-end;
  }

  .news-grid {
    grid-template-columns: 1fr;
    gap: 14px;
  }

  .state-box {
    padding: 60px 16px;
  }

  .modal {
    padding: 0;
    align-items: flex-end;
  }

  .modal-content {
    border-radius: var(--radius-lg) var(--radius-lg) 0 0;
    max-height: 92vh;
  }

  .modal-body {
    padding: 24px 16px 20px;
  }

  .modal-title {
    font-size: 18px;
  }

  .modal-cover {
    max-height: 240px;
  }

  .modal-content-text {
    font-size: 15px;
  }

  .site-footer p {
    font-size: 13px;
  }
}