@import url('https://fonts.googleapis.com/css2?family=Plus+Jakarta+Sans:ital,wght@0,400;0,500;0,700;1,400&display=swap');

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

html {
  scroll-behavior: smooth;
  font-size: 16px;
}

body {
  font-family: 'Plus Jakarta Sans', 'PingFang SC', 'Hiragino Sans GB', 'Microsoft YaHei', sans-serif;
  font-size: 1rem;
  line-height: 1.65;
  color: #000;
  background: #f5f5f0;
  overflow-x: hidden;
}

/* ===== CSS 变量 ===== */
:root {
  --primary: #3bb1ff;
  --accent: #ff5252;
  --black: #000000;
  --white: #ffffff;
  --bg: #f5f5f0;
  --card-bg: #ffffff;
  --border: 3px solid #000;
  --shadow: 5px 5px 0px #000;
  --shadow-lg: 8px 8px 0px #000;
  --nav-width: 240px;
  --font-bold: 700;
}

/* ===== 页面整体布局 ===== */
.page-shell {
  display: flex;
  min-height: 100vh;
}

.main-wrapper {
  flex: 1;
  margin-left: var(--nav-width);
  display: flex;
  flex-direction: column;
  min-height: 100vh;
}

/* ===== 侧边导航 ===== */
.side-nav {
  position: fixed;
  top: 0;
  left: 0;
  width: var(--nav-width);
  height: 100vh;
  background: var(--black);
  border-right: var(--border);
  display: flex;
  flex-direction: column;
  z-index: 100;
  overflow-y: auto;
}

.side-nav__brand {
  padding: 1.5rem 1.25rem 1rem;
  border-bottom: var(--border);
}

.brand-link {
  text-decoration: none;
  display: block;
}

.logo-text {
  font-size: 1.2rem;
  font-weight: var(--font-bold);
  color: var(--primary);
  letter-spacing: -0.02em;
  display: block;
}

.site-logo-img {
  max-width: 140px;
  height: auto;
  display: block;
}

.side-nav__list {
  list-style: none;
  padding: 0.75rem 0;
  flex: 1;
  counter-reset: nav-counter;
}

.side-nav__list li {
  counter-increment: nav-counter;
  border-bottom: 2px solid #1a1a1a;
}

.side-nav__list li a {
  display: flex;
  align-items: center;
  gap: 0.6rem;
  padding: 0.85rem 1.25rem;
  color: var(--white);
  text-decoration: none;
  font-size: 0.875rem;
  font-weight: 500;
  min-height: 48px;
  transition: background 0.15s, color 0.15s;
  line-height: 1.3;
}

.side-nav__list li a::before {
  content: counter(nav-counter, decimal-leading-zero);
  font-size: 0.7rem;
  color: var(--primary);
  font-weight: var(--font-bold);
  flex-shrink: 0;
  font-variant-numeric: tabular-nums;
}

.side-nav__list li a:hover,
.side-nav__list li a:focus-visible {
  background: var(--primary);
  color: var(--black);
  outline: none;
}

.side-nav__list li a:hover::before,
.side-nav__list li a:focus-visible::before {
  color: var(--black);
}

.side-nav__cta {
  padding: 1.25rem;
  border-top: var(--border);
}

.btn-cta {
  display: block;
  width: 100%;
  padding: 0.75rem 1rem;
  background: var(--accent);
  color: var(--white);
  font-weight: var(--font-bold);
  font-size: 0.9rem;
  text-align: center;
  text-decoration: none;
  border: var(--border);
  box-shadow: var(--shadow);
  cursor: pointer;
  min-height: 48px;
  line-height: 1.3;
  display: flex;
  align-items: center;
  justify-content: center;
  transition: transform 0.1s, box-shadow 0.1s;
}

.btn-cta:hover,
.btn-cta:focus-visible {
  transform: translate(-2px, -2px);
  box-shadow: 7px 7px 0px #000;
  outline: none;
}

.btn-cta:active {
  transform: translate(2px, 2px);
  box-shadow: 3px 3px 0px #000;
}

/* ===== Hero ===== */
.hero {
  position: relative;
  width: 100%;
  min-height: 100vh;
  background: var(--primary);
  border-bottom: var(--border);
  display: flex;
  align-items: center;
  justify-content: flex-end;
  overflow: hidden;
  padding: 4rem 3rem 6rem;
}

.hero__media {
  position: absolute;
  inset: 0;
  z-index: 0;
}

.hero-img {
  width: 100%;
  height: 100%;
  object-fit: cover;
  display: block;
  opacity: 0.25;
}

.hero__content {
  position: relative;
  z-index: 2;
  text-align: right;
  max-width: 560px;
}

.hero__badge {
  display: inline-block;
  background: var(--accent);
  color: var(--white);
  font-size: 0.75rem;
  font-weight: var(--font-bold);
  letter-spacing: 0.08em;
  padding: 0.3rem 0.8rem;
  border: 2px solid var(--black);
  box-shadow: 3px 3px 0 #000;
  margin-bottom: 1.25rem;
  text-transform: uppercase;
}

.hero__h1 {
  font-size: clamp(2.2rem, 5vw, 4rem);
  font-weight: var(--font-bold);
  line-height: 1.1;
  letter-spacing: -0.03em;
  color: var(--black);
  margin-bottom: 1rem;
}

.hero__sub {
  font-size: 1.05rem;
  color: #1a1a1a;
  margin-bottom: 2rem;
  line-height: 1.6;
  max-width: 440px;
  margin-left: auto;
}

.btn-hero {
  display: inline-flex;
  align-items: center;
  padding: 0.9rem 2rem;
  background: var(--black);
  color: var(--white);
  font-weight: var(--font-bold);
  font-size: 1rem;
  text-decoration: none;
  border: var(--border);
  box-shadow: var(--shadow-lg);
  min-height: 52px;
  transition: transform 0.1s, box-shadow 0.1s;
}

.btn-hero:hover,
.btn-hero:focus-visible {
  transform: translate(-3px, -3px);
  box-shadow: 11px 11px 0 #000;
  outline: none;
}

.btn-hero:active {
  transform: translate(2px, 2px);
  box-shadow: 3px 3px 0 #000;
}

.hero__clip {
  position: absolute;
  bottom: -2px;
  left: 0;
  right: 0;
  height: 80px;
  background: var(--bg);
  z-index: 1;
  clip-path: polygon(0 100%, 100% 100%, 100% 0);
}

/* ===== 主内容区 ===== */
main {
  flex: 1;
}

.wrap {
  max-width: 1100px;
  margin: 0 auto;
  padding: 3rem 2rem 4rem;
}

.content-section {
  display: flex;
  gap: 2.5rem;
  align-items: flex-start;
}

/* ===== Aside 侧边栏（内容左侧）===== */
.content-aside {
  width: 220px;
  flex-shrink: 0;
  position: sticky;
  top: 1.5rem;
}

.aside-inner {
  background: var(--card-bg);
  border: var(--border);
  box-shadow: var(--shadow);
  padding: 1.25rem;
}

.aside-eyebrow {
  display: block;
  font-size: 0.7rem;
  font-weight: var(--font-bold);
  letter-spacing: 0.1em;
  color: var(--accent);
  text-transform: uppercase;
  margin-bottom: 0.3rem;
}

.aside-title {
  font-size: 1rem;
  font-weight: var(--font-bold);
  margin-bottom: 1rem;
  border-bottom: 2px solid var(--black);
  padding-bottom: 0.5rem;
}

.aside-nav-list {
  list-style: none;
  counter-reset: aside-counter;
}

.aside-nav-list li {
  counter-increment: aside-counter;
  border-bottom: 1px solid #e0e0e0;
}

.aside-nav-list li:last-child {
  border-bottom: none;
}

.aside-nav-list li a {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  padding: 0.55rem 0;
  color: var(--black);
  text-decoration: none;
  font-size: 0.8rem;
  font-weight: 500;
  min-height: 40px;
  line-height: 1.3;
  transition: color 0.15s;
}

.aside-nav-list li a::before {
  content: counter(aside-counter, decimal-leading-zero);
  font-size: 0.65rem;
  color: var(--primary);
  font-weight: var(--font-bold);
  flex-shrink: 0;
}

.aside-nav-list li a:hover,
.aside-nav-list li a:focus-visible {
  color: var(--accent);
  outline: none;
}

/* ===== 正文 section ===== */
.content-article {
  flex: 1;
  min-width: 0;
}

/* ===== 正文内的 div 区块（page.content 内容）===== */
.content-article div {
  margin-bottom: 4rem;
  scroll-margin-top: 80px;
}

.content-article h2 {
  font-size: 1.7rem;
  font-weight: var(--font-bold);
  letter-spacing: -0.02em;
  line-height: 1.2;
  margin-bottom: 1rem;
  padding-bottom: 0.6rem;
  border-bottom: 3px solid var(--black);
}

.content-article h3 {
  font-size: 1.2rem;
  font-weight: var(--font-bold);
  margin-top: 1.75rem;
  margin-bottom: 0.6rem;
  color: var(--black);
}

.content-article p {
  font-size: 1rem;
  line-height: 1.75;
  margin-bottom: 1rem;
  color: #111;
}

.content-article ul,
.content-article ol {
  padding-left: 1.5rem;
  margin-bottom: 1rem;
}

.content-article li {
  font-size: 1rem;
  line-height: 1.7;
  margin-bottom: 0.4rem;
}

.content-article a {
  color: var(--black);
  text-decoration: underline;
  text-decoration-color: var(--primary);
  text-underline-offset: 3px;
  font-weight: 500;
}

.content-article a:hover {
  color: var(--accent);
  text-decoration-color: var(--accent);
}

.content-article strong {
  font-weight: var(--font-bold);
}

.content-article table {
  width: 100%;
  border-collapse: collapse;
  margin-bottom: 1.5rem;
  border: var(--border);
}

.content-article th,
.content-article td {
  padding: 0.6rem 0.85rem;
  border: 2px solid var(--black);
  font-size: 0.9rem;
  text-align: left;
}

.content-article th {
  background: var(--primary);
  font-weight: var(--font-bold);
}

.content-article blockquote {
  border-left: 5px solid var(--accent);
  padding: 0.75rem 1.25rem;
  background: #fff;
  margin: 1.25rem 0;
  box-shadow: 4px 4px 0 #000;
}

/* 小眉题 + h2/h3 相邻 */
.content-article small + h2,
.content-article small + h3 {
  margin-top: 0.25rem;
}

small.eyebrow,
.content-article small {
  display: block;
  font-size: 0.7rem;
  font-weight: var(--font-bold);
  letter-spacing: 0.1em;
  color: var(--accent);
  text-transform: uppercase;
  margin-bottom: 0.2rem;
}

/* ===== 页脚 ===== */
.site-footer {
  background: var(--black);
  border-top: var(--border);
  color: var(--white);
}

.footer-cta-block {
  background: var(--primary);
  border-bottom: var(--border);
  padding: 2.5rem 2rem;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1.5rem;
  flex-wrap: wrap;
}

.footer-cta-text {
  font-size: 1.1rem;
  font-weight: var(--font-bold);
  color: var(--black);
  max-width: 500px;
}

.footer-cta-block .btn-cta {
  background: var(--black);
  color: var(--white);
  flex-shrink: 0;
  width: auto;
  min-width: 160px;
}

.footer-cta-block .btn-cta:hover {
  background: var(--accent);
}

.footer-bar {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1.5rem;
  padding: 1.25rem 2rem;
  flex-wrap: wrap;
}

.footer-brand .logo-text {
  color: var(--primary);
  font-size: 1rem;
}

.footer-logo-link {
  text-decoration: none;
}

.footer-logo-link .site-logo-img {
  max-width: 100px;
  filter: brightness(0) invert(1);
}

.footer-nav {
  flex: 1;
}

.footer-nav-list {
  list-style: none;
  display: flex;
  flex-wrap: wrap;
  gap: 0.25rem 1.25rem;
}

.footer-nav-list li a {
  color: #ccc;
  text-decoration: none;
  font-size: 0.8rem;
  padding: 0.3rem 0;
  display: inline-block;
  min-height: 40px;
  line-height: 40px;
  transition: color 0.15s;
}

.footer-nav-list li a:hover,
.footer-nav-list li a:focus-visible {
  color: var(--primary);
  outline: none;
}

.footer-copy {
  font-size: 0.75rem;
  color: #888;
  white-space: nowrap;
}

/* ===== scroll-margin-top for sections ===== */
div[id] {
  scroll-margin-top: 72px;
}

/* ===== 动效 ===== */
@media (prefers-reduced-motion: no-preference) {
  .side-nav__list li {
    opacity: 0;
    transform: translateX(-16px);
    animation: stagger-in 0.4s forwards;
  }

  .side-nav__list li:nth-child(1) { animation-delay: 0.05s; }
  .side-nav__list li:nth-child(2) { animation-delay: 0.1s; }
  .side-nav__list li:nth-child(3) { animation-delay: 0.15s; }
  .side-nav__list li:nth-child(4) { animation-delay: 0.2s; }
  .side-nav__list li:nth-child(5) { animation-delay: 0.25s; }
  .side-nav__list li:nth-child(6) { animation-delay: 0.3s; }
  .side-nav__list li:nth-child(7) { animation-delay: 0.35s; }

  @keyframes stagger-in {
    to {
      opacity: 1;
      transform: translateX(0);
    }
  }

  .content-article div {
    opacity: 0;
    transform: translateY(24px);
    transition: opacity 0.5s ease, transform 0.5s ease;
  }

  .content-article div.is-visible {
    opacity: 1;
    transform: translateY(0);
  }

  .hero__content {
    opacity: 0;
    transform: translateX(30px);
    animation: hero-slide-in 0.6s 0.2s forwards;
  }

  @keyframes hero-slide-in {
    to {
      opacity: 1;
      transform: translateX(0);
    }
  }
}

@media (prefers-reduced-motion: reduce) {
  .content-article div {
    opacity: 1;
    transform: none;
  }
}

/* ===== 响应式 ===== */
@media (max-width: 1024px) {
  :root {
    --nav-width: 200px;
  }

  .hero__h1 {
    font-size: 2.2rem;
  }

  .content-aside {
    width: 180px;
  }
}

@media (max-width: 768px) {
  :root {
    --nav-width: 0px;
  }

  .page-shell {
    flex-direction: column;
  }

  .main-wrapper {
    margin-left: 0;
  }

  .side-nav {
    position: static;
    width: 100%;
    height: auto;
    flex-direction: row;
    flex-wrap: wrap;
    border-right: none;
    border-bottom: var(--border);
  }

  .side-nav__brand {
    padding: 0.75rem 1rem;
    border-bottom: none;
    border-right: var(--border);
    display: flex;
    align-items: center;
  }

  .side-nav__list {
    display: flex;
    flex-direction: row;
    flex-wrap: wrap;
    flex: 1;
    padding: 0;
    counter-reset: nav-counter;
  }

  .side-nav__list li {
    border-bottom: none;
    border-right: 1px solid #1a1a1a;
  }

  .side-nav__list li a {
    font-size: 0.75rem;
    padding: 0.5rem 0.75rem;
    min-height: 48px;
  }

  .side-nav__list li a::before {
    display: none;
  }

  .side-nav__cta {
    padding: 0.5rem 0.75rem;
    border-top: none;
    border-left: var(--border);
    display: flex;
    align-items: center;
  }

  .side-nav__cta .btn-cta {
    width: auto;
    padding: 0.5rem 1rem;
    font-size: 0.8rem;
  }

  .hero {
    min-height: 100svh;
    padding: 5rem 1.5rem 4rem;
    justify-content: center;
  }

  .hero__content {
    text-align: center;
    max-width: 100%;
  }

  .hero__sub {
    margin-left: 0;
    margin-right: 0;
  }

  .wrap {
    padding: 2rem 1rem 3rem;
  }

  .content-section {
    flex-direction: column;
    gap: 2rem;
  }

  .content-aside {
    width: 100%;
    position: static;
  }

  .aside-nav-list {
    display: flex;
    flex-wrap: wrap;
    gap: 0.25rem 1rem;
  }

  .aside-nav-list li {
    border-bottom: none;
  }

  .aside-nav-list li a {
    min-height: 40px;
  }

  .footer-cta-block {
    flex-direction: column;
    align-items: flex-start;
    padding: 2rem 1.25rem;
  }

  .footer-cta-block .btn-cta {
    width: 100%;
  }

  .footer-bar {
    flex-direction: column;
    align-items: flex-start;
    gap: 1rem;
    padding: 1.25rem;
  }

  .footer-nav-list {
    gap: 0.25rem 0.75rem;
  }

  .footer-copy {
    white-space: normal;
  }
}

@media (max-width: 480px) {
  .hero__h1 {
    font-size: 1.8rem;
  }

  .content-article h2 {
    font-size: 1.3rem;
  }

  .content-article h3 {
    font-size: 1.05rem;
  }

  .side-nav__list li a {
    font-size: 0.7rem;
    padding: 0.4rem 0.5rem;
  }
}