@charset "utf-8";
/* ============================================================================
   天辰娱乐 TIANCHEN · AI 学习直播
   ----------------------------------------------------------------------------
   视觉语言：星轨夜航 Orbit Night —— 深空底 + 电光青 + 星紫 + 琥珀，轨道环线贯穿全站
   结构约定：级联层（@layer）+ tc- 前缀 + 扁平 section 语义块，无页面级覆盖文件
   实现约束：零外部依赖、零图片、零框架，首屏信息不依赖脚本
   ============================================================================ */

@layer tokens, base, layout, components, sections, pages, utilities;

/* ---------------------------------------------------------------------------
   tokens · 设计令牌
   --------------------------------------------------------------------------- */
@layer tokens {
  :root {
    /* 深空底色 */
    --void:      #04060e;
    --void-2:    #070b18;
    --panel:     #0b1020;
    --panel-2:   #0f1729;
    --panel-3:   #141e36;

    /* 星轨主色 */
    --cyan:      #35e6c4;
    --cyan-2:    #14b39a;
    --cyan-dim:  rgba(53, 230, 196, .14);
    --violet:    #7b6bff;
    --violet-dim:rgba(123, 107, 255, .16);
    --amber:     #ffb454;

    /* 文本 */
    --text:      #e9eefb;
    --text-2:    #a3b0cc;
    --text-3:    #6b7893;
    --text-inv:  #04060e;

    /* 线条与光 */
    --line:      rgba(122, 160, 220, .14);
    --line-2:    rgba(122, 160, 220, .28);
    --glow-cyan: 0 0 0 1px rgba(53, 230, 196, .28), 0 24px 60px -32px rgba(53, 230, 196, .5);
    --glow-soft: 0 30px 70px -50px rgba(0, 0, 0, .9);

    /* 尺寸 */
    --shell:     1200px;
    --gutter:    clamp(18px, 4vw, 48px);
    --gap:       clamp(14px, 1.6vw, 22px);
    --r-sm:      10px;
    --r-md:      16px;
    --r-lg:      24px;
    --r-pill:    999px;
    --head-h:    74px;

    /* 字体 */
    --sans: "Segoe UI", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", system-ui, sans-serif;
    --mono: "JetBrains Mono", ui-monospace, SFMono-Regular, Consolas, Menlo, monospace;

    /* 动效 */
    --ease: cubic-bezier(.2, .7, .2, 1);
    --slow: .55s var(--ease);
  }
}

/* ---------------------------------------------------------------------------
   base · 基础重置
   --------------------------------------------------------------------------- */
@layer base {
  *, *::before, *::after { box-sizing: border-box; }

  html {
    -webkit-text-size-adjust: 100%;
    scroll-behavior: smooth;
    scroll-padding-top: calc(var(--head-h) + 16px);
  }

  body {
    margin: 0;
    background-color: var(--void);
    background-image:
      radial-gradient(1200px 620px at 78% -10%, rgba(123, 107, 255, .20), transparent 62%),
      radial-gradient(900px 520px at 8% 4%, rgba(53, 230, 196, .12), transparent 60%),
      radial-gradient(circle at 12% 32%, rgba(255, 255, 255, .05) 0 1px, transparent 1px),
      radial-gradient(circle at 62% 18%, rgba(255, 255, 255, .04) 0 1px, transparent 1px),
      radial-gradient(circle at 88% 64%, rgba(255, 255, 255, .035) 0 1px, transparent 1px);
    background-size: auto, auto, 220px 220px, 340px 340px, 460px 460px;
    background-attachment: fixed, fixed, fixed, fixed, fixed;
    color: var(--text);
    font-family: var(--sans);
    font-size: 16px;
    line-height: 1.72;
    letter-spacing: .01em;
    overflow-x: hidden;
  }

  a { color: inherit; text-decoration: none; }
  img { max-width: 100%; display: block; }
  button { font: inherit; color: inherit; }
  ul, ol { margin: 0; padding: 0; list-style: none; }

  h1, h2, h3, h4, h5 {
    margin: 0;
    line-height: 1.24;
    letter-spacing: -.01em;
    font-weight: 650;
  }

  p { margin: 0; }

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

  ::selection { background: rgba(53, 230, 196, .3); color: #fff; }
}

/* ---------------------------------------------------------------------------
   layout · 骨架
   --------------------------------------------------------------------------- */
@layer layout {
  .tc-shell {
    width: 100%;
    max-width: var(--shell);
    margin-inline: auto;
    padding-inline: var(--gutter);
  }

  .tc-main { display: block; }

  .tc-sec {
    position: relative;
    padding-block: clamp(56px, 7vw, 104px);
  }

  .tc-sec--tight { padding-block: clamp(40px, 5vw, 72px); }

  .tc-sec__head {
    display: grid;
    grid-template-columns: minmax(0, 1fr) minmax(0, .82fr);
    gap: var(--gap);
    align-items: end;
    margin-bottom: clamp(26px, 3vw, 44px);
  }

  .tc-sec__head--stack { grid-template-columns: 1fr; }

  .tc-rule {
    height: 1px;
    border: 0;
    margin: 0;
    background: linear-gradient(90deg, transparent, var(--line-2) 12%, var(--line-2) 88%, transparent);
  }

  .tc-grid { display: grid; gap: var(--gap); }
  .tc-grid--2 { grid-template-columns: repeat(2, minmax(0, 1fr)); }
  .tc-grid--3 { grid-template-columns: repeat(3, minmax(0, 1fr)); }
  .tc-grid--4 { grid-template-columns: repeat(4, minmax(0, 1fr)); }

  .tc-split {
    display: grid;
    grid-template-columns: minmax(0, 1.02fr) minmax(0, .98fr);
    gap: clamp(24px, 4vw, 60px);
    align-items: center;
  }
}

/* ---------------------------------------------------------------------------
   components · 通用组件
   --------------------------------------------------------------------------- */
@layer components {
  /* 顶栏 */
  .tc-head {
    position: fixed;
    inset: 0 0 auto;
    z-index: 90;
    height: var(--head-h);
    display: flex;
    align-items: center;
    background: rgba(4, 6, 14, .58);
    backdrop-filter: blur(14px) saturate(140%);
    border-bottom: 1px solid transparent;
    transition: background .3s var(--ease), border-color .3s var(--ease);
  }

  .tc-head.is-stuck {
    background: rgba(4, 6, 14, .88);
    border-bottom-color: var(--line);
  }

  .tc-head__bar {
    display: flex;
    align-items: center;
    gap: clamp(14px, 2.4vw, 34px);
    width: 100%;
    max-width: var(--shell);
    margin-inline: auto;
    padding-inline: var(--gutter);
  }

  .tc-logo {
    display: inline-flex;
    align-items: center;
    gap: 10px;
    font-weight: 700;
    font-size: 1.02rem;
    letter-spacing: .06em;
    white-space: nowrap;
  }

  .tc-logo__mark {
    position: relative;
    width: 26px;
    height: 26px;
    border-radius: 50%;
    border: 1px solid rgba(53, 230, 196, .55);
    flex: none;
  }

  .tc-logo__mark::before {
    content: "";
    position: absolute;
    inset: 5px;
    border-radius: 50%;
    background: radial-gradient(circle at 32% 30%, #d9fff7, var(--cyan) 58%, #0a6a5c);
    box-shadow: 0 0 16px rgba(53, 230, 196, .6);
  }

  .tc-logo__mark::after {
    content: "";
    position: absolute;
    inset: -5px -1px;
    border-radius: 50%;
    border: 1px dashed rgba(123, 107, 255, .65);
    transform: rotate(-24deg);
  }

  .tc-logo em {
    font-style: normal;
    font-family: var(--mono);
    font-size: .62rem;
    color: var(--text-3);
    letter-spacing: .22em;
    display: block;
    margin-top: 2px;
  }

  .tc-nav {
    display: flex;
    align-items: center;
    gap: 2px;
    margin-left: auto;
  }

  .tc-nav a {
    position: relative;
    padding: 8px 12px;
    border-radius: var(--r-pill);
    font-size: .9rem;
    color: var(--text-2);
    transition: color .2s var(--ease), background .2s var(--ease);
    white-space: nowrap;
  }

  .tc-nav a:hover { color: var(--text); background: rgba(255, 255, 255, .05); }

  .tc-nav a[aria-current="page"] {
    color: var(--cyan);
    background: var(--cyan-dim);
  }

  .tc-head__cta { display: flex; align-items: center; gap: 8px; margin-left: 8px; }

  .tc-burger {
    display: none;
    width: 42px;
    height: 42px;
    margin-left: auto;
    border: 1px solid var(--line-2);
    border-radius: 12px;
    background: transparent;
    cursor: pointer;
    position: relative;
  }

  .tc-burger span,
  .tc-burger span::before,
  .tc-burger span::after {
    position: absolute;
    left: 50%;
    width: 18px;
    height: 1.5px;
    background: var(--text);
    transform: translateX(-50%);
    transition: transform .3s var(--ease), opacity .2s var(--ease);
  }

  .tc-burger span { top: 50%; }
  .tc-burger span::before { content: ""; top: -6px; left: 0; transform: none; }
  .tc-burger span::after { content: ""; top: 6px; left: 0; transform: none; }

  .tc-burger[aria-expanded="true"] span { background: transparent; }
  .tc-burger[aria-expanded="true"] span::before { transform: translateY(6px) rotate(45deg); }
  .tc-burger[aria-expanded="true"] span::after { transform: translateY(-6px) rotate(-45deg); }

  /* 按钮 */
  .tc-btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: 8px;
    padding: 11px 20px;
    border-radius: var(--r-pill);
    border: 1px solid transparent;
    font-size: .9rem;
    font-weight: 600;
    letter-spacing: .02em;
    cursor: pointer;
    transition: transform .2s var(--ease), box-shadow .25s var(--ease), background .25s var(--ease), border-color .25s var(--ease);
  }

  .tc-btn--primary {
    background: linear-gradient(120deg, var(--cyan), #6ff0dc 55%, #a9fff1);
    color: #032b25;
    box-shadow: 0 16px 40px -22px rgba(53, 230, 196, .95);
  }

  .tc-btn--primary:hover { transform: translateY(-2px); box-shadow: 0 22px 48px -22px rgba(53, 230, 196, 1); }

  .tc-btn--ghost {
    border-color: var(--line-2);
    color: var(--text);
    background: rgba(255, 255, 255, .02);
  }

  .tc-btn--ghost:hover { border-color: rgba(53, 230, 196, .55); color: var(--cyan); transform: translateY(-2px); }

  .tc-btn--violet {
    background: linear-gradient(120deg, var(--violet), #a79bff);
    color: #0b0722;
    box-shadow: 0 16px 40px -24px rgba(123, 107, 255, .9);
  }

  .tc-btn--sm { padding: 8px 15px; font-size: .82rem; }

  .tc-link {
    display: inline-flex;
    align-items: center;
    gap: 6px;
    color: var(--cyan);
    font-size: .9rem;
    font-weight: 600;
    border-bottom: 1px solid rgba(53, 230, 196, .35);
    padding-bottom: 2px;
  }

  .tc-link::after { content: "→"; transition: transform .2s var(--ease); }
  .tc-link:hover::after { transform: translateX(4px); }

  /* 文本层级 */
  .tc-kicker {
    display: inline-flex;
    align-items: center;
    gap: 9px;
    font-family: var(--mono);
    font-size: .7rem;
    letter-spacing: .22em;
    text-transform: uppercase;
    color: var(--cyan);
    margin-bottom: 14px;
  }

  .tc-kicker::before {
    content: "";
    width: 22px;
    height: 1px;
    background: linear-gradient(90deg, var(--cyan), transparent);
  }

  .tc-h2 {
    font-size: clamp(1.5rem, 2.7vw, 2.25rem);
    letter-spacing: -.02em;
  }

  .tc-h2 em { font-style: normal; color: var(--cyan); }

  .tc-lead {
    color: var(--text-2);
    font-size: clamp(.94rem, 1.1vw, 1.02rem);
    max-width: 46ch;
  }

  .tc-note { color: var(--text-3); font-size: .82rem; }

  .tc-mono { font-family: var(--mono); font-variant-numeric: tabular-nums; }

  /* 胶囊标签 */
  .tc-caps {
    display: inline-flex;
    align-items: center;
    gap: 7px;
    padding: 5px 12px;
    border-radius: var(--r-pill);
    border: 1px solid var(--line-2);
    background: rgba(255, 255, 255, .03);
    font-size: .76rem;
    color: var(--text-2);
    letter-spacing: .04em;
  }

  .tc-caps--live {
    border-color: rgba(255, 180, 84, .45);
    color: var(--amber);
    background: rgba(255, 180, 84, .1);
  }

  .tc-dot {
    width: 6px;
    height: 6px;
    border-radius: 50%;
    background: currentColor;
    box-shadow: 0 0 0 3px rgba(255, 180, 84, .18);
    animation: tc-pulse 1.8s infinite;
    flex: none;
  }

  @keyframes tc-pulse {
    0%, 100% { opacity: 1; transform: scale(1); }
    50% { opacity: .45; transform: scale(.72); }
  }

  /* 卡片 */
  .tc-card {
    position: relative;
    padding: clamp(20px, 2.2vw, 28px);
    border: 1px solid var(--line);
    border-radius: var(--r-lg);
    background:
      linear-gradient(160deg, rgba(255, 255, 255, .04), rgba(255, 255, 255, 0) 42%),
      var(--panel);
    box-shadow: var(--glow-soft);
    transition: transform .3s var(--ease), border-color .3s var(--ease), background .3s var(--ease);
    overflow: hidden;
  }

  .tc-card::after {
    content: "";
    position: absolute;
    inset: auto auto 0 0;
    width: 100%;
    height: 1px;
    background: linear-gradient(90deg, var(--cyan), transparent 65%);
    opacity: 0;
    transition: opacity .3s var(--ease);
  }

  .tc-card:hover {
    transform: translateY(-4px);
    border-color: rgba(53, 230, 196, .38);
  }

  .tc-card:hover::after { opacity: 1; }

  .tc-card__no {
    font-family: var(--mono);
    font-size: .72rem;
    letter-spacing: .18em;
    color: var(--text-3);
  }

  .tc-card h3 {
    font-size: 1.06rem;
    margin: 10px 0 8px;
  }

  .tc-card p { color: var(--text-2); font-size: .9rem; }

  .tc-card__foot {
    margin-top: 18px;
    padding-top: 14px;
    border-top: 1px dashed var(--line);
    display: flex;
    flex-wrap: wrap;
    gap: 8px;
  }

  /* 折叠问答 */
  .tc-faq { border-top: 1px solid var(--line); }

  .tc-faq details {
    border-bottom: 1px solid var(--line);
    padding-block: 6px;
  }

  .tc-faq summary {
    display: flex;
    align-items: center;
    gap: 12px;
    padding: 16px 2px;
    cursor: pointer;
    font-weight: 600;
    font-size: .98rem;
    list-style: none;
  }

  .tc-faq summary::-webkit-details-marker { display: none; }

  .tc-faq summary::before {
    content: "+";
    font-family: var(--mono);
    color: var(--cyan);
    font-size: 1.1rem;
    width: 18px;
    flex: none;
  }

  .tc-faq details[open] summary::before { content: "–"; }

  .tc-faq p {
    padding: 0 0 18px 30px;
    color: var(--text-2);
    font-size: .9rem;
    max-width: 74ch;
  }

  /* 底部 */
  .tc-foot {
    margin-top: clamp(48px, 6vw, 88px);
    border-top: 1px solid var(--line);
    background: linear-gradient(180deg, rgba(11, 16, 32, .5), rgba(4, 6, 14, .95));
    padding-block: clamp(36px, 4vw, 58px) 22px;
  }

  .tc-foot__grid {
    display: grid;
    grid-template-columns: 1.4fr .8fr .8fr 1fr;
    gap: clamp(20px, 3vw, 44px);
  }

  .tc-foot h4 {
    font-size: .82rem;
    letter-spacing: .1em;
    color: var(--text);
    margin-bottom: 14px;
  }

  .tc-foot li + li { margin-top: 8px; }

  .tc-foot a { color: var(--text-2); font-size: .86rem; }
  .tc-foot a:hover { color: var(--cyan); }

  .tc-foot__about p { color: var(--text-2); font-size: .86rem; margin-top: 12px; max-width: 34ch; }

  .tc-foot__bar {
    margin-top: clamp(24px, 3vw, 40px);
    padding-top: 18px;
    border-top: 1px solid var(--line);
    display: flex;
    flex-wrap: wrap;
    gap: 10px 22px;
    justify-content: space-between;
    color: var(--text-3);
    font-size: .76rem;
  }

  /* 滚动揭示 */
  .tc-reveal {
    opacity: 0;
    transform: translateY(18px);
    transition: opacity .7s var(--ease), transform .7s var(--ease);
  }

  .tc-reveal.is-in { opacity: 1; transform: none; }
}

/* ---------------------------------------------------------------------------
   sections · 首页与全站通用区块
   --------------------------------------------------------------------------- */
@layer sections {
  /* 首屏 */
  .tc-hero {
    position: relative;
    padding-top: calc(var(--head-h) + clamp(38px, 6vw, 78px));
    padding-bottom: clamp(40px, 6vw, 82px);
    overflow: hidden;
  }

  .tc-hero::before {
    content: "";
    position: absolute;
    inset: 0;
    background-image:
      linear-gradient(rgba(122, 160, 220, .07) 1px, transparent 1px),
      linear-gradient(90deg, rgba(122, 160, 220, .07) 1px, transparent 1px);
    background-size: 92px 92px;
    mask-image: radial-gradient(80% 70% at 50% 20%, #000 10%, transparent 78%);
    pointer-events: none;
  }

  .tc-hero__inner {
    position: relative;
    display: grid;
    grid-template-columns: minmax(0, 1.06fr) minmax(0, .94fr);
    gap: clamp(26px, 4vw, 56px);
    align-items: center;
  }

  .tc-hero__tag {
    display: inline-flex;
    align-items: center;
    gap: 10px;
    padding: 6px 14px 6px 8px;
    border-radius: var(--r-pill);
    border: 1px solid var(--line-2);
    background: rgba(255, 255, 255, .03);
    font-size: .78rem;
    color: var(--text-2);
    margin-bottom: 22px;
  }

  .tc-hero__tag b {
    font-weight: 600;
    color: var(--amber);
    display: inline-flex;
    align-items: center;
    gap: 6px;
    padding: 2px 9px;
    border-radius: var(--r-pill);
    background: rgba(255, 180, 84, .12);
  }

  .tc-hero h1 {
    font-size: clamp(2rem, 4.4vw, 3.45rem);
    line-height: 1.14;
    letter-spacing: -.03em;
    font-weight: 700;
  }

  .tc-hero h1 span {
    display: block;
    background: linear-gradient(96deg, var(--cyan) 4%, #9df6e6 38%, var(--violet) 96%);
    -webkit-background-clip: text;
    background-clip: text;
    color: transparent;
  }

  .tc-hero__lead {
    margin-top: 20px;
    color: var(--text-2);
    font-size: clamp(.96rem, 1.2vw, 1.08rem);
    max-width: 48ch;
  }

  .tc-hero__acts {
    display: flex;
    flex-wrap: wrap;
    gap: 12px;
    margin-top: 28px;
  }

  .tc-hero__meta {
    display: flex;
    flex-wrap: wrap;
    gap: 18px 28px;
    margin-top: 34px;
    padding-top: 20px;
    border-top: 1px solid var(--line);
  }

  .tc-hero__meta div { font-size: .78rem; color: var(--text-3); }

  .tc-hero__meta b {
    display: block;
    font-family: var(--mono);
    font-size: 1.25rem;
    color: var(--text);
    letter-spacing: -.01em;
  }

  /* 轨道可视化 */
  .tc-orbit {
    position: relative;
    aspect-ratio: 1 / 1;
    width: min(100%, 470px);
    margin-inline: auto;
    display: grid;
    place-items: center;
  }

  .tc-orbit__ring {
    position: absolute;
    border-radius: 50%;
    border: 1px solid var(--line-2);
  }

  .tc-orbit__ring:nth-child(1) { inset: 2%; border-style: dashed; border-color: rgba(53, 230, 196, .3); animation: tc-spin 64s linear infinite; }
  .tc-orbit__ring:nth-child(2) { inset: 14%; border-color: rgba(123, 107, 255, .32); animation: tc-spin 46s linear infinite reverse; }
  .tc-orbit__ring:nth-child(3) { inset: 27%; border-style: dashed; border-color: rgba(122, 160, 220, .22); }
  .tc-orbit__ring:nth-child(4) { inset: 40%; border-color: rgba(53, 230, 196, .2); box-shadow: inset 0 0 60px rgba(53, 230, 196, .08); }

  .tc-orbit__ring::before {
    content: "";
    position: absolute;
    top: -4px;
    left: 50%;
    width: 7px;
    height: 7px;
    border-radius: 50%;
    background: var(--cyan);
    box-shadow: 0 0 14px var(--cyan);
  }

  .tc-orbit__ring:nth-child(2)::before { background: var(--violet); box-shadow: 0 0 14px var(--violet); }
  .tc-orbit__ring:nth-child(3)::before { background: var(--amber); box-shadow: 0 0 12px var(--amber); }
  .tc-orbit__ring:nth-child(4)::before { display: none; }

  @keyframes tc-spin { to { transform: rotate(360deg); } }

  .tc-orbit__core {
    position: relative;
    z-index: 2;
    width: 46%;
    aspect-ratio: 1;
    border-radius: 50%;
    display: grid;
    place-content: center;
    text-align: center;
    gap: 4px;
    background:
      radial-gradient(circle at 34% 28%, rgba(53, 230, 196, .3), transparent 62%),
      radial-gradient(circle at 70% 76%, rgba(123, 107, 255, .32), transparent 60%),
      #071022;
    border: 1px solid rgba(53, 230, 196, .35);
    box-shadow: 0 0 80px -18px rgba(53, 230, 196, .45), inset 0 0 40px rgba(4, 6, 14, .8);
  }

  .tc-orbit__core b {
    font-family: var(--mono);
    font-size: clamp(1.5rem, 3vw, 2.1rem);
    color: #eafffb;
    letter-spacing: -.02em;
  }

  .tc-orbit__core span {
    font-size: .68rem;
    letter-spacing: .2em;
    color: rgba(53, 230, 196, .8);
    text-transform: uppercase;
  }

  .tc-orbit__chip {
    position: absolute;
    z-index: 3;
    display: flex;
    align-items: center;
    gap: 8px;
    padding: 8px 13px;
    border-radius: var(--r-pill);
    border: 1px solid var(--line-2);
    background: rgba(7, 11, 24, .9);
    backdrop-filter: blur(6px);
    font-size: .76rem;
    color: var(--text-2);
    box-shadow: 0 18px 40px -26px rgba(0, 0, 0, .95);
    white-space: nowrap;
  }

  .tc-orbit__chip i {
    width: 5px;
    height: 5px;
    border-radius: 50%;
    background: var(--cyan);
    font-style: normal;
  }

  .tc-orbit__chip--a { top: 7%; left: 6%; }
  .tc-orbit__chip--b { top: 30%; right: -2%; }
  .tc-orbit__chip--c { bottom: 20%; left: -2%; }
  .tc-orbit__chip--d { bottom: 6%; right: 10%; }

  /* 直播走马灯 */
  .tc-marquee {
    position: relative;
    border-block: 1px solid var(--line);
    background: rgba(11, 16, 32, .55);
    overflow: hidden;
    padding-block: 13px;
    mask-image: linear-gradient(90deg, transparent, #000 8%, #000 92%, transparent);
  }

  .tc-marquee__track {
    display: flex;
    gap: 38px;
    width: max-content;
    animation: tc-slide 44s linear infinite;
  }

  .tc-marquee:hover .tc-marquee__track { animation-play-state: paused; }

  .tc-marquee__item {
    display: inline-flex;
    align-items: center;
    gap: 9px;
    font-size: .82rem;
    color: var(--text-2);
    white-space: nowrap;
  }

  .tc-marquee__item b { color: var(--text); font-weight: 600; }
  .tc-marquee__item span { font-family: var(--mono); color: var(--cyan); font-size: .74rem; }

  @keyframes tc-slide { from { transform: translateX(0); } to { transform: translateX(-50%); } }

  /* 学习轨道四阶段 */
  .tc-tracks {
    display: grid;
    grid-template-columns: repeat(4, minmax(0, 1fr));
    gap: 0;
    border: 1px solid var(--line);
    border-radius: var(--r-lg);
    background: linear-gradient(180deg, rgba(255, 255, 255, .03), transparent);
    overflow: hidden;
  }

  .tc-track {
    position: relative;
    padding: clamp(20px, 2.2vw, 30px) clamp(18px, 2vw, 26px) clamp(24px, 2.6vw, 34px);
    border-right: 1px solid var(--line);
    transition: background .3s var(--ease);
  }

  .tc-track:last-child { border-right: 0; }
  .tc-track:hover { background: rgba(53, 230, 196, .045); }

  .tc-track__no {
    font-family: var(--mono);
    font-size: .7rem;
    letter-spacing: .2em;
    color: var(--cyan);
  }

  .tc-track h3 { font-size: 1.02rem; margin: 12px 0 8px; }
  .tc-track p { color: var(--text-2); font-size: .86rem; }

  .tc-track__week {
    display: inline-block;
    margin-top: 14px;
    font-family: var(--mono);
    font-size: .72rem;
    color: var(--text-3);
    border-top: 1px dashed var(--line);
    padding-top: 10px;
    width: 100%;
  }

  /* 数据条 */
  .tc-stats {
    display: grid;
    grid-template-columns: repeat(4, minmax(0, 1fr));
    gap: var(--gap);
  }

  .tc-stat {
    padding: 22px 20px;
    border-radius: var(--r-md);
    border: 1px solid var(--line);
    background: linear-gradient(160deg, rgba(123, 107, 255, .08), transparent 60%), var(--panel);
  }

  .tc-stat b {
    display: block;
    font-family: var(--mono);
    font-size: clamp(1.5rem, 2.6vw, 2rem);
    color: var(--cyan);
    letter-spacing: -.03em;
  }

  .tc-stat span { font-size: .8rem; color: var(--text-3); }

  /* 步骤 */
  .tc-steps {
    counter-reset: tc-step;
    display: grid;
    grid-template-columns: repeat(4, minmax(0, 1fr));
    gap: var(--gap);
  }

  .tc-step {
    counter-increment: tc-step;
    position: relative;
    padding: 24px 20px 22px;
    border: 1px solid var(--line);
    border-radius: var(--r-md);
    background: var(--panel);
  }

  .tc-step::before {
    content: "0" counter(tc-step);
    font-family: var(--mono);
    font-size: .72rem;
    color: var(--cyan);
    letter-spacing: .18em;
  }

  .tc-step h3 { font-size: .98rem; margin: 10px 0 6px; }
  .tc-step p { color: var(--text-2); font-size: .85rem; }

  /* 讲师条目 */
  .tc-mentor {
    display: grid;
    grid-template-columns: 74px 1fr;
    gap: 16px;
    align-items: center;
    padding: 18px;
    border: 1px solid var(--line);
    border-radius: var(--r-md);
    background: rgba(255, 255, 255, .02);
    transition: border-color .3s var(--ease), transform .3s var(--ease);
  }

  .tc-mentor:hover { border-color: rgba(123, 107, 255, .45); transform: translateY(-3px); }

  .tc-mentor__ava {
    width: 74px;
    height: 74px;
    border-radius: 22px;
    display: grid;
    place-items: center;
    font-family: var(--mono);
    font-size: 1.1rem;
    letter-spacing: .02em;
    color: #041a16;
    background: linear-gradient(140deg, var(--cyan), #a5fff0 60%, #7b6bff);
    flex: none;
  }

  .tc-mentor h3 { font-size: .98rem; margin-bottom: 4px; }
  .tc-mentor p { font-size: .82rem; color: var(--text-2); }
  .tc-mentor span { display: block; margin-top: 6px; font-family: var(--mono); font-size: .7rem; color: var(--text-3); }

  /* 案例 */
  .tc-case {
    position: relative;
    display: grid;
    gap: 14px;
    padding: clamp(22px, 2.4vw, 30px);
    border: 1px solid var(--line);
    border-radius: var(--r-lg);
    background:
      radial-gradient(120% 90% at 100% 0%, rgba(123, 107, 255, .13), transparent 60%),
      var(--panel);
  }

  .tc-case__kpi {
    display: flex;
    flex-wrap: wrap;
    gap: 10px 22px;
    padding-top: 16px;
    border-top: 1px dashed var(--line);
  }

  .tc-case__kpi b {
    display: block;
    font-family: var(--mono);
    font-size: 1.18rem;
    color: var(--amber);
  }

  .tc-case__kpi span { font-size: .72rem; color: var(--text-3); }

  /* 资讯卡片 */
  .tc-post-card {
    display: flex;
    flex-direction: column;
    gap: 12px;
    padding: 24px;
    border: 1px solid var(--line);
    border-radius: var(--r-md);
    background: var(--panel);
    transition: transform .3s var(--ease), border-color .3s var(--ease);
  }

  .tc-post-card:hover { transform: translateY(-4px); border-color: rgba(53, 230, 196, .38); }

  .tc-post-card time {
    font-family: var(--mono);
    font-size: .72rem;
    color: var(--text-3);
    letter-spacing: .08em;
  }

  .tc-post-card h3 { font-size: 1.02rem; }
  .tc-post-card p { font-size: .86rem; color: var(--text-2); }
  .tc-post-card .tc-link { margin-top: auto; font-size: .82rem; align-self: flex-start; }

  /* 行动区 */
  .tc-cta {
    position: relative;
    padding: clamp(30px, 4.4vw, 62px);
    border-radius: clamp(20px, 3vw, 32px);
    border: 1px solid rgba(53, 230, 196, .3);
    background:
      radial-gradient(90% 130% at 88% 8%, rgba(53, 230, 196, .2), transparent 58%),
      radial-gradient(80% 120% at 6% 92%, rgba(123, 107, 255, .22), transparent 58%),
      #08101f;
    overflow: hidden;
  }

  .tc-cta::before {
    content: "";
    position: absolute;
    right: -120px;
    top: -120px;
    width: 360px;
    height: 360px;
    border-radius: 50%;
    border: 1px dashed rgba(53, 230, 196, .28);
    box-shadow: 0 0 0 44px rgba(53, 230, 196, .04), 0 0 0 88px rgba(123, 107, 255, .04);
    pointer-events: none;
  }

  .tc-cta__inner {
    position: relative;
    display: flex;
    flex-wrap: wrap;
    align-items: center;
    justify-content: space-between;
    gap: 22px;
  }

  .tc-cta h2 { font-size: clamp(1.35rem, 2.4vw, 1.9rem); }
  .tc-cta p { color: var(--text-2); font-size: .92rem; margin-top: 8px; max-width: 52ch; }
}

/* ---------------------------------------------------------------------------
   pages · 内页与文章
   --------------------------------------------------------------------------- */
@layer pages {
  /* 内页头 */
  .tc-ph {
    position: relative;
    padding-top: calc(var(--head-h) + clamp(30px, 4.4vw, 58px));
    padding-bottom: clamp(26px, 3.4vw, 42px);
    border-bottom: 1px solid var(--line);
    overflow: hidden;
  }

  .tc-ph::after {
    content: "";
    position: absolute;
    right: -80px;
    top: -60px;
    width: 300px;
    height: 300px;
    border-radius: 50%;
    border: 1px dashed rgba(123, 107, 255, .25);
    pointer-events: none;
  }

  .tc-crumb {
    display: flex;
    flex-wrap: wrap;
    align-items: center;
    gap: 8px;
    font-size: .76rem;
    color: var(--text-3);
    margin-bottom: 16px;
  }

  .tc-crumb a { color: var(--text-2); }
  .tc-crumb a:hover { color: var(--cyan); }
  .tc-crumb span::before { content: "/"; margin-right: 8px; color: var(--text-3); }

  .tc-ph h1 {
    font-size: clamp(1.75rem, 3.4vw, 2.6rem);
    letter-spacing: -.025em;
  }

  .tc-ph p {
    margin-top: 14px;
    color: var(--text-2);
    max-width: 64ch;
    font-size: clamp(.92rem, 1.1vw, 1rem);
  }

  .tc-ph__meta {
    display: flex;
    flex-wrap: wrap;
    gap: 8px;
    margin-top: 20px;
  }

  /* 文章 */
  .tc-article {
    display: grid;
    grid-template-columns: minmax(0, 1fr) 260px;
    gap: clamp(24px, 4vw, 56px);
    padding-block: clamp(36px, 5vw, 64px);
    align-items: start;
  }

  .tc-article__body { min-width: 0; }

  .tc-article__body h2 {
    font-size: clamp(1.18rem, 2vw, 1.42rem);
    margin: 34px 0 12px;
    padding-left: 14px;
    border-left: 2px solid var(--cyan);
  }

  .tc-article__body h2:first-child { margin-top: 0; }

  .tc-article__body h3 { font-size: 1.02rem; margin: 22px 0 8px; color: var(--cyan); }

  .tc-article__body p {
    color: var(--text-2);
    font-size: .96rem;
    margin-bottom: 13px;
  }

  .tc-article__body ul, .tc-article__body ol {
    margin: 0 0 16px;
    padding-left: 18px;
    color: var(--text-2);
    font-size: .94rem;
  }

  .tc-article__body li { margin-bottom: 7px; list-style: none; position: relative; }
  .tc-article__body li::before {
    content: "";
    position: absolute;
    left: -16px;
    top: .72em;
    width: 5px;
    height: 5px;
    border-radius: 50%;
    background: var(--cyan);
    opacity: .7;
  }

  .tc-article__body strong { color: var(--text); font-weight: 600; }

  .tc-article__body a { color: var(--cyan); border-bottom: 1px solid rgba(53, 230, 196, .35); }

  .tc-quote {
    margin: 22px 0;
    padding: 20px 24px;
    border-radius: var(--r-md);
    border: 1px solid var(--line);
    border-left: 3px solid var(--violet);
    background: linear-gradient(120deg, rgba(123, 107, 255, .1), transparent 70%);
    color: var(--text);
    font-size: .95rem;
  }

  .tc-note-box {
    margin: 22px 0;
    padding: 18px 20px;
    border-radius: var(--r-md);
    border: 1px dashed rgba(255, 180, 84, .4);
    background: rgba(255, 180, 84, .06);
    font-size: .88rem;
    color: #f4dcc0;
  }

  .tc-table-wrap { overflow-x: auto; margin: 20px 0; }

  .tc-table {
    width: 100%;
    border-collapse: collapse;
    font-size: .88rem;
    min-width: 520px;
  }

  .tc-table th, .tc-table td {
    padding: 12px 14px;
    border-bottom: 1px solid var(--line);
    text-align: left;
    color: var(--text-2);
  }

  .tc-table th {
    color: var(--text);
    font-weight: 600;
    font-size: .82rem;
    letter-spacing: .04em;
    background: rgba(255, 255, 255, .03);
  }

  .tc-aside {
    position: sticky;
    top: calc(var(--head-h) + 20px);
    padding: 22px;
    border: 1px solid var(--line);
    border-radius: var(--r-md);
    background: var(--panel);
  }

  .tc-aside h3 { font-size: .9rem; margin-bottom: 12px; }
  .tc-aside li + li { margin-top: 10px; }
  .tc-aside a { font-size: .84rem; color: var(--text-2); }
  .tc-aside a:hover { color: var(--cyan); }
  .tc-aside .tc-btn { width: 100%; margin-top: 16px; }

  /* 课程表 */
  .tc-tabs {
    display: inline-flex;
    flex-wrap: wrap;
    gap: 5px;
    padding: 5px;
    border: 1px solid var(--line);
    border-radius: var(--r-pill);
    background: rgba(255, 255, 255, .03);
    margin-bottom: 26px;
  }

  .tc-tabs [role="tab"] {
    padding: 8px 18px;
    border-radius: var(--r-pill);
    border: 0;
    background: transparent;
    color: var(--text-2);
    font-size: .85rem;
    cursor: pointer;
    transition: color .2s var(--ease), background .2s var(--ease);
  }

  .tc-tabs [role="tab"][aria-selected="true"] {
    background: var(--cyan);
    color: #04241f;
    font-weight: 600;
  }

  .tc-tabpanel[hidden] { display: none; }

  .tc-syllabus {
    border: 1px solid var(--line);
    border-radius: var(--r-md);
    overflow: hidden;
  }

  .tc-syllabus__row {
    display: grid;
    grid-template-columns: 92px 1fr auto;
    gap: 16px;
    align-items: center;
    padding: 16px 20px;
    border-bottom: 1px solid var(--line);
    background: rgba(255, 255, 255, .015);
  }

  .tc-syllabus__row:last-child { border-bottom: 0; }

  .tc-syllabus__row span:first-child {
    font-family: var(--mono);
    font-size: .74rem;
    color: var(--cyan);
    letter-spacing: .08em;
  }

  .tc-syllabus__row b { font-size: .92rem; font-weight: 600; display: block; }
  .tc-syllabus__row em { font-style: normal; font-size: .8rem; color: var(--text-3); }
  .tc-syllabus__row i {
    font-style: normal;
    font-family: var(--mono);
    font-size: .74rem;
    color: var(--text-2);
    white-space: nowrap;
  }

  /* 筛选 */
  .tc-filter {
    display: flex;
    flex-wrap: wrap;
    gap: 8px;
    margin-bottom: 24px;
  }

  .tc-filter button {
    padding: 7px 15px;
    border-radius: var(--r-pill);
    border: 1px solid var(--line);
    background: transparent;
    color: var(--text-2);
    font-size: .8rem;
    cursor: pointer;
  }

  .tc-filter button.is-on { border-color: rgba(53, 230, 196, .55); color: var(--cyan); background: var(--cyan-dim); }

  /* 表单 */
  .tc-form {
    display: grid;
    gap: 16px;
    padding: clamp(22px, 2.6vw, 32px);
    border: 1px solid var(--line);
    border-radius: var(--r-lg);
    background: var(--panel);
  }

  .tc-field { display: grid; gap: 7px; }

  .tc-field label { font-size: .8rem; color: var(--text-2); letter-spacing: .04em; }

  .tc-field input,
  .tc-field select,
  .tc-field textarea {
    width: 100%;
    padding: 12px 14px;
    border-radius: var(--r-sm);
    border: 1px solid var(--line-2);
    background: rgba(4, 6, 14, .6);
    color: var(--text);
    font-size: .92rem;
    font-family: inherit;
    transition: border-color .2s var(--ease), box-shadow .2s var(--ease);
  }

  .tc-field textarea { min-height: 118px; resize: vertical; }

  .tc-field input:focus,
  .tc-field select:focus,
  .tc-field textarea:focus {
    outline: none;
    border-color: var(--cyan);
    box-shadow: 0 0 0 3px rgba(53, 230, 196, .14);
  }

  .tc-form__row { display: grid; grid-template-columns: 1fr 1fr; gap: 16px; }

  .tc-form__tip { font-size: .76rem; color: var(--text-3); }
  .tc-form__tip a { color: var(--cyan); }

  /* 开户页步骤清单 */
  .tc-flow { display: grid; gap: 12px; }

  .tc-flow__item {
    display: grid;
    grid-template-columns: 40px 1fr;
    gap: 14px;
    padding: 18px 20px;
    border: 1px solid var(--line);
    border-radius: var(--r-md);
    background: rgba(255, 255, 255, .02);
  }

  .tc-flow__item b {
    display: grid;
    place-items: center;
    width: 40px;
    height: 40px;
    border-radius: 12px;
    background: var(--cyan-dim);
    color: var(--cyan);
    font-family: var(--mono);
    font-size: .86rem;
    border: 1px solid rgba(53, 230, 196, .3);
  }

  .tc-flow__item h3 { font-size: .95rem; margin-bottom: 4px; }
  .tc-flow__item p { font-size: .85rem; color: var(--text-2); }

  /* 学员中心仪表盘 */
  .tc-dash {
    display: grid;
    grid-template-columns: 230px 1fr;
    gap: 0;
    border: 1px solid var(--line);
    border-radius: var(--r-lg);
    background: var(--panel);
    overflow: hidden;
  }

  .tc-dash__side {
    padding: 24px 20px;
    border-right: 1px solid var(--line);
    background: rgba(4, 6, 14, .45);
  }

  .tc-dash__side li {
    padding: 9px 12px;
    border-radius: 9px;
    font-size: .86rem;
    color: var(--text-2);
  }

  .tc-dash__side li.is-on { background: var(--cyan-dim); color: var(--cyan); }

  .tc-dash__main { padding: clamp(20px, 2.4vw, 30px); display: grid; gap: 18px; }

  .tc-dash__row {
    display: flex;
    flex-wrap: wrap;
    align-items: center;
    justify-content: space-between;
    gap: 10px;
    padding: 16px 18px;
    border: 1px solid var(--line);
    border-radius: var(--r-md);
    background: rgba(255, 255, 255, .02);
  }

  .tc-bar {
    height: 5px;
    border-radius: var(--r-pill);
    background: rgba(122, 160, 220, .16);
    overflow: hidden;
    width: 100%;
  }

  .tc-bar i {
    display: block;
    height: 100%;
    border-radius: inherit;
    background: linear-gradient(90deg, var(--cyan), var(--violet));
  }

  /* 联系信息块 */
  .tc-info {
    display: grid;
    gap: 14px;
    padding: 20px;
    border-left: 2px solid rgba(53, 230, 196, .45);
    background: linear-gradient(90deg, rgba(53, 230, 196, .06), transparent 70%);
  }

  .tc-info div { font-size: .88rem; color: var(--text-2); }
  .tc-info b { display: block; color: var(--text); font-size: .8rem; letter-spacing: .08em; margin-bottom: 3px; }

  /* 404 */
  .tc-404 {
    min-height: 74vh;
    display: grid;
    place-items: center;
    text-align: center;
    padding-top: var(--head-h);
  }

  .tc-404 b {
    font-family: var(--mono);
    font-size: clamp(3.6rem, 12vw, 7rem);
    line-height: 1;
    background: linear-gradient(100deg, var(--cyan), var(--violet));
    -webkit-background-clip: text;
    background-clip: text;
    color: transparent;
    letter-spacing: -.04em;
  }

  .tc-404 h1 { font-size: clamp(1.2rem, 2.4vw, 1.7rem); margin-top: 12px; }
  .tc-404 p { color: var(--text-2); margin-top: 10px; font-size: .92rem; }
  .tc-404 .tc-hero__acts { justify-content: center; }
}

/* ---------------------------------------------------------------------------
   utilities · 响应式与可访问性
   --------------------------------------------------------------------------- */
@layer utilities {
  .tc-hide { display: none !important; }
  .tc-mt-l { margin-top: clamp(24px, 3vw, 40px); }
  .tc-center { text-align: center; }

  @media (max-width: 1080px) {
    .tc-nav a { padding: 8px 9px; font-size: .85rem; }
    .tc-head__cta .tc-btn--ghost { display: none; }
    .tc-article { grid-template-columns: 1fr; }
    .tc-aside { position: static; }
    .tc-foot__grid { grid-template-columns: 1fr 1fr; }
  }

  @media (max-width: 940px) {
    .tc-hero__inner { grid-template-columns: 1fr; }
    .tc-orbit { width: min(100%, 360px); margin-top: 12px; }
    .tc-hero__meta { margin-top: 26px; }
    .tc-split { grid-template-columns: 1fr; }
    .tc-grid--3, .tc-grid--4, .tc-tracks, .tc-steps, .tc-stats { grid-template-columns: repeat(2, minmax(0, 1fr)); }
    .tc-tracks { border-radius: var(--r-md); }
    .tc-track:nth-child(2n) { border-right: 0; }
    .tc-track:nth-child(-n + 2) { border-bottom: 1px solid var(--line); }
    .tc-sec__head { grid-template-columns: 1fr; }
    .tc-dash { grid-template-columns: 1fr; }
    .tc-dash__side { border-right: 0; border-bottom: 1px solid var(--line); }
    .tc-dash__side ul { display: flex; flex-wrap: wrap; gap: 6px; }
  }

  @media (max-width: 860px) {
    .tc-nav {
      position: fixed;
      inset: var(--head-h) 0 auto;
      flex-direction: column;
      align-items: stretch;
      gap: 2px;
      padding: 14px var(--gutter) 22px;
      background: rgba(4, 6, 14, .97);
      border-bottom: 1px solid var(--line);
      transform: translateY(-12px);
      opacity: 0;
      visibility: hidden;
      transition: opacity .25s var(--ease), transform .25s var(--ease), visibility .25s;
    }

    .tc-nav.is-open { opacity: 1; visibility: visible; transform: none; }
    .tc-nav a { padding: 11px 12px; font-size: .95rem; border-radius: 10px; }
    .tc-head__cta { display: none; }
    .tc-burger { display: block; }
    .tc-form__row { grid-template-columns: 1fr; }
  }

  @media (max-width: 620px) {
    body { font-size: 15px; }
    .tc-grid--2, .tc-grid--3, .tc-grid--4, .tc-tracks, .tc-steps, .tc-stats { grid-template-columns: 1fr; }
    .tc-track { border-right: 0; border-bottom: 1px solid var(--line); }
    .tc-track:last-child { border-bottom: 0; }
    .tc-syllabus__row { grid-template-columns: 72px 1fr; }
    .tc-syllabus__row i { grid-column: 2; }
    .tc-foot__grid { grid-template-columns: 1fr; }
    .tc-hero__meta { gap: 16px 22px; }
    .tc-orbit__chip--b { right: 0; }
    .tc-orbit__chip--c { left: 0; }
    .tc-sidestep { display: none; }
    .tc-cta::before { display: none; }
  }

  @media (prefers-reduced-motion: reduce) {
    html { scroll-behavior: auto; }
    *, *::before, *::after {
      animation-duration: .001ms !important;
      animation-iteration-count: 1 !important;
      transition-duration: .001ms !important;
    }
    .tc-reveal { opacity: 1; transform: none; }
  }
}