/* ========================================
   个人笔记站 · Apple Design 风格
   灵感来源：apple.com 的排版语言
   ======================================== */

:root {
  --white: #ffffff;
  --bg-light: #f5f5f7;
  --ink: #1d1d1f;
  --ink-secondary: #6e6e73;
  --ink-muted: #86868b;
  --link: #0066cc;
  --link-hover: #0077ed;
  --divider: #d2d2d7;
  --radius-lg: 20px;
  --radius-md: 14px;
  --max-width: 1024px;
  --text-width: 720px;
}

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

html {
  scroll-behavior: smooth;
}

body {
  font-family: -apple-system, BlinkMacSystemFont, "SF Pro Display", "SF Pro Text",
    "Helvetica Neue", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", sans-serif;
  background: var(--white);
  color: var(--ink);
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility;
}

a {
  color: var(--link);
  text-decoration: none;
  transition: color 0.2s ease;
}

a:hover {
  color: var(--link-hover);
  text-decoration: underline;
}

/* ---------- 导航栏（毛玻璃） ---------- */
.site-nav {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  z-index: 100;
  height: 48px;
  background: rgba(255, 255, 255, 0.72);
  backdrop-filter: saturate(180%) blur(20px);
  -webkit-backdrop-filter: saturate(180%) blur(20px);
  border-bottom: 1px solid rgba(0, 0, 0, 0.06);
}

.nav-inner {
  max-width: var(--max-width);
  height: 100%;
  margin: 0 auto;
  padding: 0 22px;
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.nav-logo {
  font-size: 15px;
  font-weight: 600;
  color: var(--ink);
  letter-spacing: -0.01em;
}

.nav-logo:hover {
  color: var(--ink);
  text-decoration: none;
}

.nav-links {
  display: flex;
  gap: 32px;
  list-style: none;
}

.nav-links a {
  font-size: 12.5px;
  font-weight: 400;
  color: rgba(29, 29, 31, 0.8);
  letter-spacing: 0.01em;
}

.nav-links a:hover,
.nav-links a.active {
  color: var(--ink);
  text-decoration: none;
}

/* ---------- Hero 区域 ---------- */
.hero {
  padding: 168px 22px 96px;
  text-align: center;
  background: var(--white);
}

.hero-eyebrow {
  font-size: 17px;
  font-weight: 600;
  color: var(--ink-muted);
  margin-bottom: 8px;
}

.hero h1 {
  font-size: clamp(44px, 7vw, 72px);
  font-weight: 700;
  letter-spacing: -0.025em;
  line-height: 1.08;
  margin-bottom: 16px;
}

.hero h1 .gradient-text {
  background: linear-gradient(90deg, #0090f7, #ba62fc 55%, #f2416b);
  -webkit-background-clip: text;
  background-clip: text;
  -webkit-text-fill-color: transparent;
}

.hero .hero-sub {
  font-size: clamp(19px, 2.6vw, 26px);
  font-weight: 400;
  color: var(--ink-secondary);
  letter-spacing: -0.01em;
  max-width: 640px;
  margin: 0 auto 28px;
}

.hero-cta {
  display: inline-flex;
  gap: 20px;
  align-items: center;
}

.btn-primary {
  display: inline-block;
  background: #0071e3;
  color: #fff;
  font-size: 15px;
  font-weight: 400;
  padding: 11px 24px;
  border-radius: 980px;
  transition: background 0.2s ease;
}

.btn-primary:hover {
  background: #0077ed;
  color: #fff;
  text-decoration: none;
}

.link-arrow {
  font-size: 17px;
}

.link-arrow::after {
  content: " ›";
}

/* ---------- 通用 Section ---------- */
.section {
  padding: 96px 22px;
}

.section-gray {
  background: var(--bg-light);
}

.section-inner {
  max-width: var(--max-width);
  margin: 0 auto;
}

.section-head {
  text-align: center;
  margin-bottom: 56px;
}

.section-head h2 {
  font-size: clamp(32px, 4.5vw, 48px);
  font-weight: 700;
  letter-spacing: -0.02em;
  line-height: 1.1;
}

.section-head p {
  font-size: 19px;
  color: var(--ink-secondary);
  margin-top: 12px;
}

/* ---------- 笔记卡片网格 ---------- */
.note-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 24px;
}

.note-card {
  display: block;
  background: var(--white);
  border-radius: var(--radius-lg);
  padding: 40px 36px;
  color: inherit;
  transition: transform 0.3s cubic-bezier(0.25, 0.1, 0.25, 1), box-shadow 0.3s ease;
  box-shadow: 0 1px 2px rgba(0, 0, 0, 0.04);
  border: 1px solid rgba(0, 0, 0, 0.04);
}

.section:not(.section-gray) .note-card {
  background: var(--bg-light);
}

.note-card:hover {
  transform: translateY(-4px);
  box-shadow: 0 12px 32px rgba(0, 0, 0, 0.08);
  text-decoration: none;
  color: inherit;
}

.note-card .card-tag {
  display: inline-block;
  font-size: 12px;
  font-weight: 600;
  letter-spacing: 0.02em;
  color: var(--link);
  margin-bottom: 12px;
}

.note-card h3 {
  font-size: 24px;
  font-weight: 600;
  letter-spacing: -0.015em;
  line-height: 1.25;
  margin-bottom: 10px;
}

.note-card p {
  font-size: 15px;
  color: var(--ink-secondary);
  line-height: 1.55;
  display: -webkit-box;
  -webkit-line-clamp: 3;
  -webkit-box-orient: vertical;
  overflow: hidden;
}

.note-card .card-date {
  display: block;
  margin-top: 18px;
  font-size: 13px;
  color: var(--ink-muted);
}

.note-card .card-more {
  display: inline-block;
  margin-top: 14px;
  font-size: 15px;
  color: var(--link);
}

/* ---------- 特性展示区 ---------- */
.feature-row {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 64px;
  align-items: center;
}

.feature-text h3 {
  font-size: 32px;
  font-weight: 700;
  letter-spacing: -0.02em;
  margin-bottom: 14px;
}

.feature-text p {
  font-size: 17px;
  color: var(--ink-secondary);
  line-height: 1.65;
}

.feature-visual {
  background: linear-gradient(135deg, #f5f5f7, #e8e8ed);
  border-radius: var(--radius-lg);
  aspect-ratio: 4 / 3;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 64px;
}

/* ---------- 关于页 ---------- */
.about-hero {
  padding: 168px 22px 40px;
  text-align: center;
}

.about-hero h1 {
  font-size: clamp(36px, 5vw, 56px);
  font-weight: 700;
  letter-spacing: -0.02em;
}

.about-hero p {
  font-size: 21px;
  color: var(--ink-secondary);
  max-width: 600px;
  margin: 16px auto 0;
}

.about-block {
  max-width: var(--text-width);
  margin: 0 auto;
  padding: 24px 22px 64px;
}

.about-block h2 {
  font-size: 28px;
  font-weight: 600;
  letter-spacing: -0.015em;
  margin: 48px 0 14px;
}

.about-block p {
  font-size: 17px;
  color: var(--ink-secondary);
  line-height: 1.75;
}

.about-block .skill-chips {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
  list-style: none;
  margin-top: 8px;
}

.skill-chips li {
  background: var(--bg-light);
  border-radius: 980px;
  padding: 8px 18px;
  font-size: 14px;
  color: var(--ink);
}

/* ---------- 笔记正文页 ---------- */
.article-hero {
  padding: 152px 22px 48px;
  text-align: center;
}

.article-hero .article-tag {
  font-size: 14px;
  font-weight: 600;
  color: var(--link);
}

.article-hero h1 {
  font-size: clamp(32px, 4.6vw, 52px);
  font-weight: 700;
  letter-spacing: -0.022em;
  line-height: 1.12;
  max-width: 820px;
  margin: 14px auto 0;
}

.article-hero .article-meta {
  margin-top: 20px;
  font-size: 14px;
  color: var(--ink-muted);
}

.article-body {
  max-width: var(--text-width);
  margin: 0 auto;
  padding: 24px 22px 80px;
  font-size: 18px;
  line-height: 1.8;
  color: var(--ink);
}

.article-body h2 {
  font-size: 26px;
  font-weight: 600;
  letter-spacing: -0.015em;
  margin: 48px 0 16px;
}

.article-body h3 {
  font-size: 21px;
  font-weight: 600;
  margin: 36px 0 12px;
}

.article-body p {
  margin-bottom: 20px;
}

.article-body ul,
.article-body ol {
  margin: 0 0 20px 24px;
}

.article-body li {
  margin-bottom: 8px;
}

.article-body blockquote {
  margin: 32px 0;
  padding: 4px 0 4px 24px;
  border-left: 3px solid var(--divider);
  font-size: 20px;
  color: var(--ink-secondary);
  font-weight: 500;
}

.article-body pre {
  background: var(--bg-light);
  border-radius: var(--radius-md);
  padding: 20px 24px;
  overflow-x: auto;
  font-size: 15px;
  line-height: 1.6;
  margin: 24px 0;
}

.article-body code {
  font-family: "SF Mono", SFMono-Regular, ui-monospace, Menlo, Consolas, monospace;
}

.article-body p code,
.article-body li code {
  background: var(--bg-light);
  padding: 2px 7px;
  border-radius: 6px;
  font-size: 0.88em;
}

.back-link {
  font-size: 15px;
}

/* ---------- 页脚 ---------- */
.site-footer {
  background: var(--bg-light);
  padding: 40px 22px;
  border-top: 1px solid var(--divider);
}

.footer-inner {
  max-width: var(--max-width);
  margin: 0 auto;
  font-size: 12px;
  color: var(--ink-muted);
}

.footer-inner .footer-nav {
  display: flex;
  gap: 24px;
  padding-bottom: 16px;
  border-bottom: 1px solid var(--divider);
  margin-bottom: 16px;
}

.footer-inner .footer-nav a {
  color: rgba(29, 29, 31, 0.8);
}

.footer-inner .copyright {
  line-height: 1.8;
}

/* ---------- 渐入动画 ---------- */
.fade-in {
  opacity: 0;
  transform: translateY(18px);
  transition: opacity 0.7s ease, transform 0.7s cubic-bezier(0.25, 0.1, 0.25, 1);
}

.fade-in.show {
  opacity: 1;
  transform: translateY(0);
}

/* ---------- 响应式 ---------- */
@media (max-width: 768px) {
  .hero {
    padding: 132px 22px 72px;
  }
  .section {
    padding: 72px 22px;
  }
  .note-grid {
    grid-template-columns: 1fr;
  }
  .feature-row {
    grid-template-columns: 1fr;
    gap: 32px;
  }
  .nav-links {
    gap: 20px;
  }
}