:root {
  --ink: #172033;
  --muted: #69748a;
  --line: #dfe5ef;
  --paper: #f5f7fb;
  --white: #ffffff;
  --blue: #246bfd;
  --blue-dark: #1645c5;
  --cyan: #7be4db;
  --violet: #8b7cf6;
  --shadow: 0 24px 70px rgba(28, 47, 86, 0.12);
  --radius: 28px;
  --shell: min(1180px, calc(100% - 48px));
}

* { box-sizing: border-box; }
html { scroll-behavior: smooth; }
body {
  margin: 0;
  color: var(--ink);
  background: var(--paper);
  font-family: "Microsoft YaHei UI", "PingFang SC", "Noto Sans CJK SC", system-ui, sans-serif;
  -webkit-font-smoothing: antialiased;
}
a { color: inherit; text-decoration: none; }
button, summary { font: inherit; }
.shell { width: var(--shell); margin-inline: auto; }
.sr-only {
  position: absolute; width: 1px; height: 1px; padding: 0; margin: -1px;
  overflow: hidden; clip: rect(0, 0, 0, 0); white-space: nowrap; border: 0;
}
.skip-link {
  position: fixed; left: 20px; top: -60px; z-index: 100;
  padding: 12px 18px; border-radius: 12px; color: #fff; background: var(--ink);
  transition: top .2s ease;
}
.skip-link:focus { top: 18px; }

.site-header {
  position: sticky; top: 0; z-index: 50;
  border-bottom: 1px solid rgba(223, 229, 239, .8);
  background: rgba(245, 247, 251, .86);
  backdrop-filter: blur(18px);
}
.nav-shell { min-height: 82px; display: flex; align-items: center; justify-content: space-between; gap: 32px; }
.brand { display: inline-flex; align-items: center; gap: 13px; }
.brand-mark {
  display: grid; place-items: center; width: 44px; height: 44px; border-radius: 14px;
  color: #fff; background: linear-gradient(145deg, var(--blue), var(--blue-dark));
  box-shadow: 0 10px 24px rgba(36, 107, 253, .22); font-weight: 900; letter-spacing: -2px;
}
.brand strong, .brand small { display: block; }
.brand strong { font-size: 16px; letter-spacing: .06em; }
.brand small { margin-top: 4px; color: #8a93a6; font-size: 8px; letter-spacing: .18em; }
.main-nav { display: flex; align-items: center; gap: 34px; font-size: 14px; font-weight: 700; }
.main-nav a { position: relative; color: #4e586d; }
.main-nav a:not(.nav-accent)::after {
  content: ""; position: absolute; left: 0; right: 100%; bottom: -8px; height: 2px;
  background: var(--blue); transition: right .2s ease;
}
.main-nav a:hover::after, .main-nav a:focus-visible::after { right: 0; }
.nav-accent { padding: 11px 18px; border-radius: 999px; color: #fff !important; background: var(--ink); }
.menu-button { display: none; border: 0; background: transparent; padding: 8px; }
.menu-button > span:not(.sr-only) { display: block; width: 24px; height: 2px; margin: 5px; background: var(--ink); }

.hero { min-height: 690px; display: grid; grid-template-columns: 1.02fr .98fr; align-items: center; gap: 46px; padding-block: 84px 70px; }
.eyebrow { margin: 0 0 18px; color: var(--blue); font-size: 12px; font-weight: 900; letter-spacing: .2em; }
.eyebrow span { display: inline-block; width: 28px; height: 2px; margin: 0 10px 4px 0; background: currentColor; }
.hero h1 { margin: 0; font-size: clamp(50px, 5.5vw, 76px); line-height: 1.12; letter-spacing: -.055em; }
.hero h1 em { color: var(--blue); font-style: normal; }
.hero-intro { max-width: 590px; margin: 28px 0 0; color: var(--muted); font-size: 18px; line-height: 1.9; }
.hero-actions { display: flex; gap: 14px; margin-top: 36px; }
.button { display: inline-flex; justify-content: center; align-items: center; gap: 12px; padding: 15px 22px; border: 1px solid transparent; border-radius: 14px; font-size: 14px; font-weight: 800; transition: transform .2s ease, box-shadow .2s ease, background .2s ease; }
.button:hover { transform: translateY(-2px); }
.button-primary { color: #fff; background: var(--blue); box-shadow: 0 12px 28px rgba(36, 107, 253, .22); }
.button-primary:hover { box-shadow: 0 18px 34px rgba(36, 107, 253, .28); }
.button-ghost { border-color: var(--line); background: rgba(255, 255, 255, .65); }
.button-ghost:hover { background: #fff; }
.hero-tags { display: flex; flex-wrap: wrap; gap: 9px; margin: 30px 0 0; padding: 0; list-style: none; }
.hero-tags li { padding: 8px 12px; border: 1px solid var(--line); border-radius: 999px; color: #6d778b; background: rgba(255,255,255,.6); font-size: 12px; }

.hero-visual { position: relative; min-height: 500px; display: grid; place-items: center; overflow: hidden; }
.hero-visual::before {
  content: ""; position: absolute; width: 430px; height: 430px; border-radius: 50%;
  background: radial-gradient(circle at 38% 35%, rgba(123, 228, 219, .95), rgba(36, 107, 253, .78) 58%, rgba(139, 124, 246, .45));
  filter: saturate(.9); box-shadow: inset 0 0 80px rgba(255,255,255,.35);
}
.visual-orbit { position: absolute; border: 1px solid rgba(36,107,253,.15); border-radius: 50%; }
.orbit-one { width: 500px; height: 500px; }
.orbit-two { width: 560px; height: 390px; transform: rotate(-19deg); }
.code-window { position: relative; z-index: 2; width: min(440px, 92%); overflow: hidden; border: 1px solid rgba(255,255,255,.45); border-radius: 22px; background: #11192b; box-shadow: 0 34px 80px rgba(22, 37, 76, .34); transform: rotate(-2deg); }
.code-titlebar { height: 54px; display: grid; grid-template-columns: 1fr auto 1fr; align-items: center; padding: 0 18px; border-bottom: 1px solid rgba(255,255,255,.08); color: #9aa8c2; font-size: 11px; }
.code-titlebar div { display: flex; gap: 7px; }
.code-titlebar i { width: 9px; height: 9px; border-radius: 50%; background: #ff6c6c; }
.code-titlebar i:nth-child(2) { background: #ffcc5a; }
.code-titlebar i:nth-child(3) { background: #47d18c; }
.code-titlebar b { justify-self: end; }
.code-window pre { margin: 0; padding: 34px 28px 30px; overflow: hidden; color: #d8e1f4; font: 14px/2 "Cascadia Code", Consolas, monospace; }
.line-no { color: #53617a; user-select: none; }
.purple { color: #c4a7ff; }
.blue { color: #79c3ff; }
.green { color: #8fe0ba; }
.code-status { display: flex; justify-content: space-between; padding: 11px 18px; color: #8493ad; background: rgba(36,107,253,.14); font-size: 10px; }
.code-status i { display: inline-block; width: 6px; height: 6px; margin-right: 5px; border-radius: 50%; background: #47d18c; box-shadow: 0 0 0 4px rgba(71,209,140,.12); }
.float-card { position: absolute; z-index: 3; padding: 12px 16px; border: 1px solid rgba(255,255,255,.7); border-radius: 13px; color: var(--ink); background: rgba(255,255,255,.88); box-shadow: 0 14px 30px rgba(22, 37, 76, .13); backdrop-filter: blur(12px); font: 700 12px Consolas, monospace; }
.float-a { top: 69px; right: 8px; transform: rotate(4deg); }
.float-b { left: 0; bottom: 75px; transform: rotate(-5deg); }
.float-c { right: 18px; bottom: 39px; transform: rotate(3deg); }

.topic-strip { border-block: 1px solid var(--line); background: #fff; }
.topic-grid { display: grid; grid-template-columns: repeat(3, 1fr); }
.topic-grid article { display: flex; align-items: center; gap: 18px; min-height: 126px; padding: 26px 34px; border-right: 1px solid var(--line); }
.topic-grid article:first-child { border-left: 1px solid var(--line); }
.topic-grid article > span { color: var(--blue); font: 800 12px Consolas, monospace; }
.topic-grid strong, .topic-grid small { display: block; }
.topic-grid strong { margin-bottom: 8px; font-size: 15px; }
.topic-grid small { color: var(--muted); font-size: 12px; }

.section { padding-block: 118px; }
.section-heading { display: flex; align-items: end; justify-content: space-between; gap: 40px; margin-bottom: 48px; }
.section-heading h2, .path-intro h2, .about-card h2 { margin: 0; font-size: clamp(34px, 4vw, 50px); line-height: 1.18; letter-spacing: -.035em; }
.section-heading > p { max-width: 460px; margin: 0; color: var(--muted); line-height: 1.8; }
.notes-grid { display: grid; grid-template-columns: 1.2fr 1fr 1fr; gap: 18px; }
.note-card { min-height: 410px; display: flex; flex-direction: column; justify-content: space-between; padding: 28px; border: 1px solid var(--line); border-radius: 22px; background: rgba(255,255,255,.76); transition: transform .22s ease, box-shadow .22s ease, border-color .22s ease; }
.note-card:hover { transform: translateY(-6px); border-color: #c9d7f5; box-shadow: var(--shadow); }
.note-featured { background: linear-gradient(150deg, #fff 0%, #eef4ff 100%); }
.note-meta { display: flex; justify-content: space-between; color: #929bad; font: 700 10px Consolas, monospace; text-transform: uppercase; letter-spacing: .08em; }
.note-meta span { padding: 6px 9px; border-radius: 7px; color: var(--blue); background: #eaf1ff; }
.note-index { color: #abb3c2; font: 700 10px Consolas, monospace; letter-spacing: .12em; }
.note-card h3 { margin: 14px 0 16px; font-size: 24px; line-height: 1.45; letter-spacing: -.02em; }
.note-card > div > p:last-child { margin: 0; color: var(--muted); font-size: 14px; line-height: 1.8; }
.note-card details { border-top: 1px solid var(--line); padding-top: 18px; }
.note-card summary { display: flex; justify-content: space-between; cursor: pointer; color: #4f5a70; font-size: 13px; font-weight: 800; list-style: none; }
.note-card summary::-webkit-details-marker { display: none; }
.note-card details[open] summary span { transform: rotate(45deg); }
.note-card details p { margin: 14px 0 0; color: var(--muted); font-size: 13px; line-height: 1.7; }

.project-section { padding-block: 118px; color: #fff; background: #11182a; }
.section-heading.light .eyebrow { color: #79a5ff; }
.section-heading.light > p { color: #9ca8bd; }
.project-grid { display: grid; grid-template-columns: repeat(3, 1fr); gap: 18px; }
.project-card { min-height: 430px; padding: 26px; overflow: hidden; border: 1px solid rgba(255,255,255,.12); border-radius: 22px; background: #182238; transition: transform .22s ease, border-color .22s ease; }
.project-card:hover { transform: translateY(-6px); border-color: rgba(255,255,255,.3); }
.project-top { display: flex; justify-content: space-between; color: #aeb9cc; font: 700 10px Consolas, monospace; letter-spacing: .14em; }
.project-top b { display: grid; place-items: center; width: 30px; height: 30px; border: 1px solid rgba(255,255,255,.15); border-radius: 50%; }
.project-icon, .project-terminal, .project-chart { height: 155px; margin: 26px 0; border-radius: 17px; }
.project-icon { position: relative; background: linear-gradient(140deg, #2b79ff, #1751d8); }
.project-icon span { position: absolute; border-radius: 9px; background: rgba(255,255,255,.92); box-shadow: 0 10px 24px rgba(0,0,0,.12); }
.project-icon span:nth-child(1) { width: 38%; height: 22%; left: 13%; top: 20%; }
.project-icon span:nth-child(2) { width: 31%; height: 52%; right: 13%; top: 20%; }
.project-icon span:nth-child(3) { width: 38%; height: 22%; left: 13%; bottom: 20%; }
.project-terminal { display: flex; flex-direction: column; justify-content: center; gap: 14px; padding: 25px; color: #0f523f; background: #92ead2; font: 700 12px Consolas, monospace; }
.project-terminal i { padding: 9px 11px; border-radius: 8px; background: rgba(255,255,255,.48); font-style: normal; }
.project-chart { display: flex; align-items: end; justify-content: center; gap: 11px; padding: 28px; background: linear-gradient(145deg, #8b7cf6, #6750db); }
.project-chart span { width: 13%; border-radius: 6px 6px 2px 2px; background: rgba(255,255,255,.88); }
.project-chart span:nth-child(1) { height: 25%; }.project-chart span:nth-child(2) { height: 48%; }.project-chart span:nth-child(3) { height: 36%; }.project-chart span:nth-child(4) { height: 72%; }.project-chart span:nth-child(5) { height: 88%; }
.project-card h3 { margin: 0 0 12px; font-size: 23px; }
.project-card p { margin: 0; color: #aeb8cb; font-size: 14px; line-height: 1.75; }
.project-card ul { display: flex; flex-wrap: wrap; gap: 7px; margin: 22px 0 0; padding: 0; list-style: none; }
.project-card li { padding: 6px 9px; border: 1px solid rgba(255,255,255,.13); border-radius: 999px; color: #b8c2d4; font: 10px Consolas, monospace; }
.project-note { margin: 25px 0 0; color: #7f8ba0; font-size: 12px; text-align: center; }

.learning-path { display: grid; grid-template-columns: .88fr 1.12fr; gap: 90px; align-items: start; }
.path-intro { position: sticky; top: 140px; }
.path-intro > p:last-child { margin: 28px 0 0; color: var(--muted); line-height: 1.8; }
.path-list { margin: 0; padding: 0; list-style: none; border-top: 1px solid var(--line); }
.path-list li { display: grid; grid-template-columns: 70px 1fr; gap: 18px; padding: 32px 12px; border-bottom: 1px solid var(--line); }
.path-list > li > span { color: var(--blue); font: 800 12px Consolas, monospace; }
.path-list h3 { margin: 0 0 9px; font-size: 20px; }
.path-list p { margin: 0; color: var(--muted); line-height: 1.7; }

.about-section { padding-bottom: 118px; }
.about-card { position: relative; display: grid; grid-template-columns: 80px 1fr 240px; gap: 34px; align-items: center; padding: 54px; overflow: hidden; border-radius: var(--radius); color: #fff; background: linear-gradient(135deg, #1d64f3, #183faa); box-shadow: 0 28px 70px rgba(27, 74, 183, .2); }
.about-card::after { content: ""; position: absolute; width: 340px; height: 340px; right: -160px; top: -190px; border: 70px solid rgba(255,255,255,.08); border-radius: 50%; }
.about-card .eyebrow { color: #bcd3ff; }
.about-mark { align-self: start; font: 800 86px/1 Georgia, serif; color: rgba(255,255,255,.32); }
.about-lead { margin: 24px 0 15px; font-size: 19px; font-weight: 700; line-height: 1.75; }
.about-lead + p { margin: 0; color: #d8e4ff; font-size: 14px; line-height: 1.8; }
.about-badge { position: relative; z-index: 2; padding: 23px; border: 1px solid rgba(255,255,255,.25); border-radius: 18px; background: rgba(255,255,255,.1); backdrop-filter: blur(8px); }
.about-badge span, .about-badge strong { display: block; }
.about-badge span { margin-bottom: 9px; color: #bcd3ff; font-size: 11px; }
.about-badge strong { font-size: 15px; letter-spacing: .08em; }

.site-footer { color: #fff; background: #0d1321; }
.footer-inner { min-height: 150px; display: flex; align-items: center; justify-content: space-between; gap: 32px; }
.footer-inner strong { font-size: 16px; }
.footer-inner p { margin: 7px 0 0; color: #7f8ba0; font-size: 12px; }
.footer-meta { text-align: right; }
.footer-meta a { color: #aab5c8; font-size: 12px; transition: color .2s ease; }
.footer-meta a:hover, .footer-meta a:focus-visible { color: #fff; }

.reveal { opacity: 0; transform: translateY(22px); transition: opacity .6s ease, transform .6s ease; }
.reveal.is-visible { opacity: 1; transform: none; }

@media (max-width: 980px) {
  :root { --shell: min(100% - 34px, 760px); }
  .menu-button { display: block; }
  .main-nav { position: absolute; left: 17px; right: 17px; top: 73px; display: none; flex-direction: column; align-items: stretch; gap: 6px; padding: 15px; border: 1px solid var(--line); border-radius: 18px; background: rgba(255,255,255,.98); box-shadow: var(--shadow); }
  .main-nav.is-open { display: flex; }
  .main-nav a { padding: 12px; }
  .main-nav a::after { display: none; }
  .nav-accent { text-align: center; }
  .hero { grid-template-columns: 1fr; gap: 22px; padding-top: 72px; }
  .hero-copy { text-align: center; }
  .hero-intro { margin-inline: auto; }
  .hero-actions, .hero-tags { justify-content: center; }
  .hero-visual { min-height: 480px; }
  .topic-grid article { padding-inline: 18px; }
  .notes-grid, .project-grid { grid-template-columns: 1fr; }
  .note-card { min-height: 340px; }
  .project-card { min-height: 390px; }
  .learning-path { grid-template-columns: 1fr; gap: 50px; }
  .path-intro { position: static; }
  .about-card { grid-template-columns: 55px 1fr; }
  .about-badge { grid-column: 2; }
}

@media (max-width: 680px) {
  :root { --shell: calc(100% - 28px); --radius: 22px; }
  .nav-shell { min-height: 72px; }
  .brand-mark { width: 40px; height: 40px; }
  .brand small { display: none; }
  .hero { min-height: auto; padding-block: 64px 50px; }
  .hero h1 { font-size: clamp(40px, 12vw, 55px); }
  .hero-intro { font-size: 16px; }
  .hero-actions { flex-direction: column; }
  .button { width: 100%; }
  .hero-visual { min-height: 380px; }
  .hero-visual::before { width: 310px; height: 310px; }
  .orbit-one { width: 350px; height: 350px; }
  .orbit-two { width: 370px; height: 280px; }
  .code-window { width: 94%; transform: rotate(-1deg); }
  .code-window pre { padding: 25px 17px; font-size: 11px; }
  .float-card { padding: 9px 11px; font-size: 10px; }
  .float-a { top: 32px; right: 0; }.float-b { left: 0; bottom: 30px; }.float-c { right: 4px; bottom: 9px; }
  .topic-grid { grid-template-columns: 1fr; padding-block: 5px; }
  .topic-grid article { min-height: 100px; border-right: 0; border-bottom: 1px solid var(--line); }
  .topic-grid article:first-child { border-left: 0; }
  .topic-grid article:last-child { border-bottom: 0; }
  .section, .project-section { padding-block: 84px; }
  .section-heading { align-items: start; flex-direction: column; gap: 18px; }
  .section-heading h2, .path-intro h2, .about-card h2 { font-size: 36px; }
  .section-heading > p { font-size: 14px; }
  .note-card { padding: 23px; }
  .note-card h3 { font-size: 22px; }
  .project-card { padding: 22px; }
  .learning-path { gap: 35px; }
  .path-list li { grid-template-columns: 50px 1fr; padding-inline: 5px; }
  .about-section { padding-bottom: 84px; }
  .about-card { grid-template-columns: 1fr; gap: 15px; padding: 30px 24px; }
  .about-mark { display: none; }
  .about-badge { grid-column: 1; margin-top: 10px; }
  .about-lead { font-size: 17px; }
  .footer-inner { min-height: 170px; flex-direction: column; align-items: flex-start; justify-content: center; }
  .footer-meta { text-align: left; }
}

@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  *, *::before, *::after { animation-duration: .01ms !important; transition-duration: .01ms !important; }
  .reveal { opacity: 1; transform: none; }
}