/* ===== Links ===== */
a {
  color: #f97316;
  text-decoration: none;
}

a:hover {
  text-decoration: underline;
}

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

html {
  scroll-behavior: smooth;
}

body {
  background-color: #0f0f0f;
  color: #e8e8e8;
  font-family:
    "Inter",
    -apple-system,
    BlinkMacSystemFont,
    "PingFang SC",
    "Microsoft YaHei",
    sans-serif;
  font-size: 18px;
  line-height: 1.8;
  -webkit-font-smoothing: antialiased;
}

/* ===== 分隔屏 ===== */
.divider-screen {
  position: relative;
  min-height: 100vh;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  text-align: center;
  padding: 0 24px;
}

.divider-screen .main-title {
  font-size: 64px;
  font-weight: 700;
  line-height: 1.1;
  color: #e8e8e8;
}

.divider-screen .main-title .accent {
  color: #f97316;
}

.divider-screen .sub-title {
  font-size: 22px;
  font-weight: 400;
  color: #888888;
  margin-top: 24px;
  line-height: 1.5;
  max-width: 560px;
}

/* ===== 内容区 ===== */
.content-section {
  max-width: 760px;
  margin: 0 auto;
  padding: 80px 24px;
}

.section-title {
  font-size: 40px;
  font-weight: 700;
  line-height: 1.2;
  margin-bottom: 40px;
}

.subsection-title {
  font-size: 24px;
  font-weight: 600;
  line-height: 1.4;
  margin: 32px 0 16px;
  color: #e8e8e8;
}

/* ===== 段落 ===== */
p {
  margin-bottom: 24px;
  color: #e8e8e8;
}

/* ===== 引用块 ===== */
blockquote {
  border-left: 4px solid #f97316;
  background: #1a1a1a;
  padding: 20px 24px;
  border-radius: 0 8px 8px 0;
  margin: 24px 0;
  font-size: 20px;
  line-height: 1.7;
  color: #e8e8e8;
}

blockquote cite {
  display: block;
  margin-top: 12px;
  font-size: 15px;
  font-style: normal;
  color: #888888;
}

/* ===== 分隔线 ===== */
hr {
  border: none;
  border-top: 1px solid #2a2a2a;
  margin: 48px 0;
}

/* ===== 强调文字 ===== */
strong {
  color: #f97316;
  font-weight: 600;
}

/* ===== 列表 ===== */
.content-list {
  margin: 16px 0 24px;
  padding-left: 22px;
  color: #e8e8e8;
}

.content-list li {
  margin-bottom: 8px;
}

.card-list {
  list-style: none;
  padding: 0;
  margin: 0;
}

.card-list li {
  position: relative;
  padding-left: 14px;
  margin-bottom: 10px;
  font-size: 15px;
  color: #c8c8c8;
  line-height: 1.6;
}

.card-list li::before {
  content: "·";
  position: absolute;
  left: 0;
  color: #888888;
}

/* ===== 通用卡片 ===== */
.card {
  background: #1a1a1a;
  border: 1px solid #2a2a2a;
  border-radius: 12px;
  padding: 24px;
  transition:
    border-color 0.2s ease,
    transform 0.2s ease;
}

.card:hover {
  border-color: #3a3a3a;
  transform: translateY(-2px);
}

/* ===== 两栏对比卡片 ===== */
.card-grid-2 {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 24px;
  margin: 32px 0;
}

.card-grid-2 .card-header {
  height: 4px;
  margin: -24px -24px 20px -24px;
  border-radius: 12px 12px 0 0;
}

.card-grid-2 .card--left .card-header {
  background: #888888;
}

.card-grid-2 .card--right .card-header {
  background: #f97316;
}

.card-grid-2 .card--junior .card-header {
  background: #3b82f6;
}

.card-grid-2 .card--senior .card-header {
  background: #888888;
}

/* ===== 2×2 网格卡片 ===== */
.card-grid-4 {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 20px;
  margin: 32px 0;
}

.card-grid-4 .card--conclusion {
  background: rgba(249, 115, 22, 0.08);
  border-color: #f97316;
}

/* ===== 三列卡片 ===== */
.card-grid-3 {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 20px;
  margin: 32px 0;
}

.card-title {
  font-size: 16px;
  font-weight: 600;
  color: #e8e8e8;
  margin-bottom: 10px;
}

.card-body {
  font-size: 15px;
  color: #888888;
  line-height: 1.7;
}

/* ===== 表格 ===== */
table {
  width: 100%;
  border-collapse: collapse;
  margin: 32px 0;
  font-size: 16px;
}

thead tr {
  background: #1e1e1e;
}

th {
  padding: 14px 16px;
  text-align: left;
  font-weight: 600;
  color: #e8e8e8;
  border-bottom: 1px solid #2a2a2a;
}

tbody tr:nth-child(odd) {
  background: #161616;
}

tbody tr:nth-child(even) {
  background: #1a1a1a;
}

td {
  padding: 14px 16px;
  color: #888888;
  border-bottom: 1px solid #2a2a2a;
}

td strong {
  color: #e8e8e8;
}

/* ===== 封面 ===== */
.cover-meta {
  margin-top: 16px;
  font-size: 15px;
  color: #555555;
}

.cover-footer {
  position: absolute;
  bottom: 16px;
  left: 0;
  right: 0;
  text-align: center;
  font-size: 13px;
  color: #444444;
}

.scroll-hint {
  position: absolute;
  bottom: 80px;
  left: 50%;
  font-size: 20px;
  color: #444444;
  animation: bounce 2s ease-in-out infinite;
  user-select: none;
}

@keyframes bounce {
  0%,
  100% {
    transform: translateX(-50%) translateY(0);
  }
  50% {
    transform: translateX(-50%) translateY(8px);
  }
}

/* ===== 讨论区 ===== */
.discussion-spacer {
  min-height: 120px;
}

.question-primary {
  font-size: 28px;
  font-weight: 600;
  line-height: 1.4;
  color: #f97316;
  margin: 32px 0 12px;
}

.hint-text {
  font-size: 15px;
  color: #888888;
  margin-bottom: 24px;
}

/* ===== 页脚 ===== */
.site-footer {
  text-align: center;
  padding: 48px 24px;
  font-size: 13px;
  color: #444444;
  line-height: 1.8;
}

.site-footer p {
  margin-bottom: 8px;
  color: #444444;
}

/* ===== 入场动画 ===== */
.animate-in {
  opacity: 0;
  transform: translateY(24px);
  transition:
    opacity 0.5s ease,
    transform 0.5s ease;
}

.animate-in.visible {
  opacity: 1;
  transform: translateY(0);
}

@media (prefers-reduced-motion: reduce) {
  html {
    scroll-behavior: auto;
  }

  .animate-in {
    opacity: 1;
    transform: none;
    transition: none;
  }

  .scroll-hint {
    animation: none;
  }

  .card:hover {
    transform: none;
  }
}

/* ===== 响应式 ===== */
@media (max-width: 1023px) {
  .content-section {
    padding: 60px 32px;
  }

  .card-grid-2,
  .card-grid-3 {
    grid-template-columns: 1fr;
  }
}

@media (max-width: 767px) {
  .divider-screen .main-title {
    font-size: 40px;
  }

  .section-title {
    font-size: 28px;
  }

  body {
    font-size: 16px;
  }

  .card-grid-2,
  .card-grid-3,
  .card-grid-4 {
    grid-template-columns: 1fr;
  }

  blockquote {
    font-size: 17px;
  }

  .question-primary {
    font-size: 22px;
  }
}