@import url('https://fonts.googleapis.com/css2?family=Didact+Gothic&family=Poiret+One&display=swap');

:root {
  --ink: #000000;
  --panel: #08090e;
  --panel-2: #0b0d14;
  --line: rgba(108, 148, 255, 0.24);
  --line-soft: rgba(226, 234, 255, 0.10);
  --fg: #e9ecf5;
  --body: #cbd2e2;
  --dim: #98a2ba;
  --blue: #6fa4ff;
  --gold: #e6c689;
  --radius: 10px;
  --rail: 240px;
  --font-display: 'Poiret One', 'PingFang SC', 'Microsoft YaHei', system-ui, sans-serif;
  --font-body: 'Didact Gothic', 'PingFang SC', 'Microsoft YaHei', system-ui, sans-serif;
}

*,
*::before,
*::after {
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
  color-scheme: dark;
  -webkit-text-size-adjust: 100%;
}

body {
  margin: 0;
  background: var(--ink);
  color: var(--body);
  font-family: var(--font-body);
  font-size: 1rem;
  line-height: 1.78;
  letter-spacing: 0.01em;
  overflow-x: hidden;
}

h1, h2, h3, h4 {
  font-family: var(--font-display);
  font-weight: 400;
  color: #fff;
  line-height: 1.24;
}

p {
  margin: 0 0 1rem;
}

a {
  color: var(--blue);
  text-decoration: none;
}

img {
  max-width: 100%;
  height: auto;
}

hr {
  border: 0;
}

[id] {
  scroll-margin-top: 26px;
}

:focus-visible {
  outline: 2px solid var(--blue);
  outline-offset: 3px;
  border-radius: 4px;
}

.shell {
  min-height: 100svh;
}

/* ---------- 左侧竖排导航 ---------- */

.rail {
  position: fixed;
  inset: 0 auto 0 0;
  width: var(--rail);
  display: flex;
  flex-direction: column;
  gap: 1.5rem;
  padding: 2.1rem 1.1rem 1.6rem;
  overflow-y: auto;
  background: linear-gradient(180deg, #06080f 0%, #000 62%);
  border-right: 1px solid var(--line);
  z-index: 30;
}

.brand {
  display: inline-flex;
  align-items: center;
  gap: 0.55rem;
  font-family: var(--font-display);
  font-size: 1.12rem;
  letter-spacing: 0.2em;
  color: #fff;
  text-shadow: 0 0 12px rgba(111, 164, 255, 0.35);
  min-height: 40px;
  padding: 0.2rem 0.15rem;
}

.brand-txt {
  border-bottom: 1px solid var(--line);
  padding-bottom: 0.35rem;
}

.brand-img {
  height: 26px;
  width: auto;
  display: block;
}

.menu {
  display: none;
  min-height: 44px;
  padding: 0.5rem 1.1rem;
  font: inherit;
  font-size: 0.95rem;
  letter-spacing: 0.16em;
  color: var(--fg);
  background: transparent;
  border: 1px solid var(--line);
  border-radius: 8px;
  cursor: pointer;
}

.rail nav ul {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  gap: 0.12rem;
  counter-reset: navi;
}

.rail nav li {
  counter-increment: navi;
}

.rail nav a {
  display: flex;
  align-items: center;
  gap: 0.6rem;
  min-height: 44px;
  padding: 0.55rem 0.6rem;
  font-size: 1rem;
  color: var(--dim);
  border-left: 1px solid transparent;
  border-radius: 0 8px 8px 0;
  transition: color 0.25s ease, background 0.25s ease, border-color 0.25s ease;
}

.rail nav a::before {
  content: counter(navi, decimal-leading-zero);
  font-family: var(--font-display);
  font-size: 0.78rem;
  letter-spacing: 0.1em;
  color: rgba(120, 158, 255, 0.55);
}

.rail nav a:hover,
.rail nav a:focus-visible {
  color: #fff;
  background: rgba(111, 164, 255, 0.07);
  border-left-color: var(--blue);
}

.rail nav li:nth-child(2) a,
.rail nav li:nth-child(3) a {
  border-bottom: 1px solid rgba(255, 255, 255, 0.05);
}

.top {
  margin-top: auto;
  min-height: 42px;
  padding: 0.45rem 0.7rem;
  font: inherit;
  font-size: 0.9rem;
  letter-spacing: 0.16em;
  color: var(--dim);
  background: transparent;
  border: 1px solid var(--line-soft);
  border-radius: 8px;
  cursor: pointer;
  transition: color 0.25s ease, border-color 0.25s ease;
}

.top:hover,
.top:focus-visible {
  color: var(--gold);
  border-color: var(--gold);
}

/* ---------- 主内容 ---------- */

.stage {
  margin-left: var(--rail);
  display: block;
}

main {
  display: block;
}

.hero {
  position: relative;
  min-height: 100svh;
  display: flex;
  flex-direction: column;
  justify-content: center;
  align-items: flex-start;
  gap: 0.4rem;
  padding: clamp(2rem, 7vw, 5.5rem);
  background:
    radial-gradient(120% 90% at 78% -12%, rgba(28, 58, 138, 0.42) 0%, rgba(0, 0, 0, 0) 58%),
    #000;
  border-bottom: 1px solid var(--line-soft);
}

.hero h1 {
  margin: 0;
  font-size: clamp(2.7rem, 10.5vw, 7.6rem);
  line-height: 0.98;
  letter-spacing: 0.02em;
  max-width: 18ch;
  text-shadow: 0 0 26px rgba(111, 164, 255, 0.26);
}

.hero-desc {
  margin: 1.1rem 0 0;
  max-width: 52ch;
  font-size: 1.05rem;
  color: var(--dim);
}

.badge {
  position: absolute;
  top: clamp(1.2rem, 4vw, 2.6rem);
  right: clamp(1.2rem, 4vw, 2.6rem);
  min-width: 132px;
  padding: 0.75rem 1rem 0.85rem;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  background: rgba(8, 11, 20, 0.72);
  backdrop-filter: blur(2px);
}

.badge h2 {
  margin: 0 0 0.5rem;
  font-size: 1rem;
  letter-spacing: 0.28em;
  color: #fff;
  text-shadow: 0 0 10px rgba(230, 198, 137, 0.3);
}

.badge hr {
  margin: 0;
  width: 42px;
  border-top: 1px solid var(--gold);
}

.body-wrap {
  display: grid;
  gap: 1.5rem;
  max-width: 920px;
  margin: 0 auto;
  padding: clamp(1.1rem, 4vw, 3.2rem) clamp(1rem, 4vw, 2.4rem) 1rem;
}

.body-wrap > article {
  padding: clamp(1.15rem, 3vw, 2.3rem);
  border: 1px solid var(--line-soft);
  border-radius: var(--radius);
  background: var(--panel);
}

.body-wrap > article:nth-child(even) {
  background: var(--panel-2);
}

.body-wrap h2 {
  margin: 0 0 0.75rem;
  font-size: clamp(1.55rem, 3.1vw, 2.15rem);
  letter-spacing: 0.05em;
}

.body-wrap h2 + hr,
.body-wrap h3 + hr {
  width: 58px;
  margin: 0 0 1.15rem;
  border-top: 1px solid var(--line);
}

.body-wrap h3 {
  margin: 1.7rem 0 0.5rem;
  font-size: 1.16rem;
  color: var(--gold);
}

.body-wrap p,
.body-wrap li {
  color: var(--body);
}

.body-wrap ul,
.body-wrap ol {
  margin: 0 0 1.1rem;
  padding-left: 1.25rem;
  display: grid;
  gap: 0.45rem;
}

.body-wrap li::marker {
  color: var(--blue);
}

.body-wrap a {
  text-decoration: underline;
  text-underline-offset: 3px;
}

.body-wrap a:hover {
  color: #fff;
}

.body-wrap figure {
  margin: 1.2rem 0;
  padding: 0.6rem;
  border: 1px solid var(--line-soft);
  border-radius: var(--radius);
}

.body-wrap figure img,
.body-wrap p img {
  display: block;
  width: 100%;
  border-radius: 6px;
}

.body-wrap figcaption {
  margin-top: 0.5rem;
  font-size: 0.95rem;
  color: var(--dim);
}

.body-wrap aside {
  margin: 1.3rem 0;
  padding: 0.9rem 1.1rem;
  border: 1px solid var(--line);
  border-left: 2px solid var(--blue);
  border-radius: var(--radius);
  background: #05070c;
}

.body-wrap blockquote {
  margin: 1.3rem 0;
  padding: 0.15rem 0 0.15rem 1.05rem;
  border-left: 2px solid var(--gold);
  color: var(--dim);
}

.body-wrap table {
  width: 100%;
  border-collapse: collapse;
  margin: 1.1rem 0;
  font-size: 0.98rem;
}

.body-wrap th,
.body-wrap td {
  padding: 0.55rem 0.7rem;
  border: 1px solid var(--line-soft);
  text-align: left;
}

.body-wrap th {
  color: #fff;
  font-weight: 400;
  background: rgba(111, 164, 255, 0.07);
}

.body-wrap code {
  padding: 0.05rem 0.35rem;
  border-radius: 4px;
  background: #10131c;
  font-size: 0.95em;
}

/* ---------- 订阅与页脚 ---------- */

.signup {
  max-width: 620px;
  margin: clamp(1.4rem, 4vw, 2.8rem) auto 0;
  padding: clamp(1rem, 3vw, 1.8rem);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  background: var(--panel);
}

.signup form {
  display: flex;
  flex-wrap: wrap;
  gap: 0.6rem;
}

.signup input {
  flex: 1 1 210px;
  min-height: 46px;
  padding: 0.55rem 0.95rem;
  font: inherit;
  color: var(--fg);
  background: #000;
  border: 1px solid var(--line-soft);
  border-radius: 8px;
}

.signup input::placeholder {
  color: #6f788c;
}

.signup button {
  min-height: 46px;
  padding: 0.55rem 1.5rem;
  font: inherit;
  letter-spacing: 0.18em;
  color: var(--gold);
  background: transparent;
  border: 1px solid var(--gold);
  border-radius: 8px;
  cursor: pointer;
  transition: background 0.25s ease, color 0.25s ease;
}

.signup button:hover,
.signup button:focus-visible {
  background: rgba(230, 198, 137, 0.12);
  color: #fff;
}

footer {
  margin-top: clamp(1.6rem, 4vw, 2.8rem);
  padding: 2rem 1rem 2.8rem;
  text-align: center;
  border-top: 1px solid var(--line-soft);
  color: var(--dim);
}

footer p {
  margin: 0 0 0.35rem;
  letter-spacing: 0.18em;
}

footer small {
  font-size: 0.95rem;
  letter-spacing: 0.1em;
  color: #79839a;
}

/* ---------- 滚动显现 ---------- */

.reveal {
  opacity: 0;
  transform: translateY(18px);
  transition: opacity 0.62s ease var(--d, 0ms), transform 0.62s ease var(--d, 0ms);
}

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

/* ---------- 窄屏 ---------- */

@media (max-width: 900px) {
  [id] {
    scroll-margin-top: 86px;
  }

  .rail {
    inset: 0 0 auto 0;
    width: auto;
    height: auto;
    flex-direction: row;
    flex-wrap: wrap;
    align-items: center;
    gap: 0.5rem 0.8rem;
    padding: 0.55rem 0.9rem;
    overflow: visible;
    border-right: 0;
    border-bottom: 1px solid var(--line);
    background: #000;
  }

  .brand {
    font-size: 1rem;
    letter-spacing: 0.14em;
  }

  .menu {
    display: inline-flex;
    align-items: center;
    margin-left: auto;
  }

  .rail nav {
    display: none;
    width: 100%;
    padding-bottom: 0.5rem;
  }

  .rail[data-open="true"] nav {
    display: block;
  }

  .rail nav a {
    border-left: 0;
    border-bottom: 1px solid rgba(255, 255, 255, 0.05);
    border-radius: 6px;
  }

  .top {
    display: none;
  }

  .stage {
    margin-left: 0;
    padding-top: 62px;
  }

  .hero {
    min-height: calc(100svh - 62px);
    padding: 2.2rem 1.15rem 3rem;
    justify-content: center;
  }

  .hero h1 {
    font-size: clamp(2.4rem, 12vw, 3.6rem);
  }

  .hero-desc {
    font-size: 1rem;
  }

  .badge {
    position: static;
    align-self: flex-start;
    margin-bottom: 0.4rem;
    min-width: 0;
    padding: 0.55rem 0.8rem 0.65rem;
  }

  .badge h2 {
    font-size: 0.95rem;
    letter-spacing: 0.2em;
  }

  .body-wrap {
    padding: 1.1rem 0.9rem 0.6rem;
  }

  .signup {
    margin: 1.2rem 0.9rem 0;
  }
}

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

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

  * {
    animation-duration: 0.01ms !important;
    transition-duration: 0.01ms !important;
  }
}

button[aria-expanded]{min-width:44px;min-height:44px}