/* ===== 全局基础 ===== */
:root {
  --bg: #ffffff;            /* 页面背景 */
  --text: #1d1d1f;          /* 主文字颜色（接近 Apple 的深灰黑） */
  --muted: #6e6e73;         /* 次要文字 */
  --accent: #0071e3;        /* Apple 蓝，用于按钮和链接 */
  --line: #e8e8ed;          /* 分隔线 */
  --card-bg: #f5f5f7;       /* 卡片底色（浅灰） */
}

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

html {
  scroll-behavior: smooth;      /* 锚点平滑滚动 */
  scroll-padding-top: 56px;     /* 顶部留出导航栏高度，避免锚点被遮挡 */
}

body {
  font-family: -apple-system, BlinkMacSystemFont, "SF Pro Text", "PingFang SC",
    "Hiragino Sans GB", "Microsoft YaHei", "Segoe UI", Roboto, sans-serif;
  background: var(--bg);
  color: var(--text);
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
}

/* 页面容器：居中的最大宽度 */
.container {
  max-width: 1024px;
  margin: 0 auto;
  padding: 0 24px;
}

/* ===== 顶部导航（毛玻璃效果） ===== */
.nav {
  position: sticky;
  top: 0;
  z-index: 100;
  background: rgba(255, 255, 255, 0.8);
  backdrop-filter: saturate(180%) blur(20px);   /* 苹果风格毛玻璃 */
  border-bottom: 1px solid var(--line);
}

.nav-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 56px;
}

.brand {
  font-size: 20px;
  font-weight: 700;
  color: var(--text);
  text-decoration: none;
}

.nav-links {
  display: flex;
  gap: 28px;
}

/* 导航右侧：链接 + 语言切换按钮 */
.nav-right {
  display: flex;
  align-items: center;
  gap: 24px;
}

/* 语言切换按钮：胶囊描边样式 */
.lang-btn {
  background: transparent;
  border: 1px solid var(--line);
  border-radius: 980px;
  padding: 6px 14px;
  font-size: 14px;
  font-family: inherit;
  color: var(--text);
  cursor: pointer;
  transition: border-color 0.2s, color 0.2s;
}

.lang-btn:hover {
  border-color: var(--accent);
  color: var(--accent);
}

.nav-links a {
  font-size: 15px;
  color: var(--text);
  text-decoration: none;
  opacity: 0.85;
  transition: opacity 0.2s;
}

.nav-links a:hover {
  opacity: 1;
}

/* ===== 首屏 Hero ===== */
.hero {
  text-align: center;
  padding: 130px 0 110px;
}

.hero-title {
  font-size: clamp(56px, 10vw, 96px);   /* 响应式超大标题 */
  font-weight: 700;
  letter-spacing: -0.03em;
  line-height: 1.1;
}

.hero-sub {
  margin-top: 14px;
  font-size: clamp(20px, 3vw, 28px);
  font-weight: 600;
  color: var(--text);
}

/* 知识库页面首屏：比主页稍紧凑 */
.kb-hero {
  padding: 90px 0 70px;
}

.hero-desc {
  margin-top: 12px;
  font-size: 17px;
  color: var(--muted);
  max-width: 560px;
  margin-left: auto;
  margin-right: auto;
}

/* Apple 风格胶囊按钮 */
.btn {
  display: inline-block;
  margin-top: 30px;
  padding: 12px 28px;
  border-radius: 980px;
  background: var(--accent);
  color: #fff;
  font-size: 16px;
  text-decoration: none;
  transition: transform 0.2s, box-shadow 0.2s;
}

.btn:hover {
  transform: scale(1.04);
  box-shadow: 0 4px 16px rgba(0, 113, 227, 0.35);
}

/* ===== 内容区块 ===== */
.section {
  padding: 90px 0;
}

/* 灰色背景区块（区分内容层次） */
.section-gray {
  background: var(--card-bg);
}

.section-title {
  text-align: center;
  font-size: 34px;
  font-weight: 700;
  letter-spacing: -0.01em;
  margin-bottom: 24px;
}

.section-text {
  text-align: center;
  font-size: 18px;
  color: var(--muted);
  max-width: 640px;
  margin: 0 auto;
}

/* 作品卡片：圆角 + 悬停微上浮 */
.cards {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(240px, 1fr));
  gap: 20px;
  margin-top: 40px;
}

.card {
  background: var(--bg);
  border-radius: 20px;
  padding: 36px 28px;
  text-align: center;
  transition: transform 0.25s ease, box-shadow 0.25s ease;
}

.card:hover {
  transform: translateY(-4px);
  box-shadow: 0 12px 32px rgba(0, 0, 0, 0.08);
}

.card h3 {
  font-size: 20px;
  margin-bottom: 8px;
}

.card p {
  font-size: 15px;
  color: var(--muted);
}

/* 知识卡片作为链接时的样式 */
a.card {
  display: block;
  text-decoration: none;
  color: inherit;
}

.card-cta {
  margin-top: 10px;
  color: var(--accent);
  font-weight: 600;
}

/* ===== 文章页排版 ===== */
.article {
  padding: 48px 24px 80px;
}

.article-head {
  text-align: center;
  margin-bottom: 40px;
}

.back-link {
  color: var(--accent);
  text-decoration: none;
  font-size: 15px;
}

.back-link:hover {
  text-decoration: underline;
}

.article-head h1 {
  font-size: clamp(28px, 5vw, 44px);
  font-weight: 700;
  letter-spacing: -0.01em;
  line-height: 1.2;
  margin: 14px 0 8px;
}

.article-meta {
  color: var(--muted);
  font-size: 14px;
}

.article-body {
  max-width: 780px;
  margin: 0 auto;
  font-size: 16.5px;
  line-height: 1.8;
}

.article-body h2 {
  font-size: 26px;
  font-weight: 700;
  margin: 40px 0 16px;
  padding-bottom: 8px;
  border-bottom: 1px solid var(--line);
}

.article-body h3 {
  font-size: 20px;
  font-weight: 600;
  margin: 28px 0 12px;
}

.article-body p {
  margin: 14px 0;
}

.article-body ul,
.article-body ol {
  margin: 12px 0;
  padding-left: 24px;
}

.article-body li {
  margin: 6px 0;
}

.article-body a {
  color: var(--accent);
  text-decoration: none;
}

.article-body a:hover {
  text-decoration: underline;
}

.article-body blockquote {
  border-left: 3px solid var(--accent);
  background: var(--card-bg);
  padding: 12px 18px;
  border-radius: 0 12px 12px 0;
  margin: 16px 0;
  color: var(--muted);
}

.article-body blockquote p {
  margin: 6px 0;
}

.article-body pre {
  background: #1d1d1f;
  color: #f5f5f7;
  padding: 16px 18px;
  border-radius: 12px;
  overflow-x: auto;
  font-size: 13.5px;
  line-height: 1.6;
}

.article-body code {
  font-family: ui-monospace, SFMono-Regular, Consolas, "Courier New", monospace;
}

.article-body :not(pre) > code {
  background: var(--card-bg);
  padding: 2px 6px;
  border-radius: 6px;
  font-size: 14px;
  color: var(--accent);
}

.article-body table {
  border-collapse: collapse;
  width: 100%;
  margin: 18px 0;
  font-size: 14.5px;
  display: block;
  overflow-x: auto;
}

.article-body th,
.article-body td {
  border: 1px solid var(--line);
  padding: 8px 12px;
  text-align: left;
  white-space: nowrap;
}

.article-body th {
  background: var(--card-bg);
  font-weight: 600;
}

.article-body img {
  max-width: 100%;
  border-radius: 12px;
}

.article-body hr {
  border: none;
  border-top: 1px solid var(--line);
  margin: 32px 0;
}

/* ===== 页脚 ===== */
.footer {
  border-top: 1px solid var(--line);
  padding: 28px 0;
  text-align: center;
  font-size: 14px;
  color: var(--muted);
}

/* ===== 滚动渐显动画 ===== */
.reveal {
  opacity: 0;
  transform: translateY(24px);
  transition: opacity 0.7s ease, transform 0.7s ease;
}

.reveal.visible {
  opacity: 1;
  transform: none;
}

/* ===== 移动端适配 ===== */
@media (max-width: 640px) {
  .hero {
    padding: 90px 0 70px;
  }

  .section {
    padding: 64px 0;
  }

  .nav-links {
    gap: 16px;
  }

  .nav-right {
    gap: 14px;
  }

  .nav-links a {
    font-size: 14px;
  }

  .lang-btn {
    padding: 5px 10px;
    font-size: 13px;
  }
}