/* ============================================================
   MultiEdge — 多云边缘网络
   Design tokens: 深色为主，支持 data-theme="light" 与系统偏好
   ============================================================ */

:root {
  --bg:            #07090d;
  --bg-alt:        #0a0d13;
  --surface:       rgba(255,255,255,.032);
  --surface-2:     rgba(255,255,255,.055);
  --line:          rgba(255,255,255,.085);
  --line-strong:   rgba(255,255,255,.16);
  --text:          #e8eef6;
  --text-2:        #9aa7b8;
  --text-3:        #67748a;

  --cyan:          #22d3ee;
  --indigo:        #818cf8;
  --teal:          #5eead4;
  --violet:        #a78bfa;
  --sky:           #38bdf8;
  --amber:         #fbbf24;

  --grad:          linear-gradient(100deg, #22d3ee 0%, #60a5fa 45%, #a78bfa 100%);
  --grad-soft:     linear-gradient(100deg, rgba(34,211,238,.18), rgba(167,139,250,.18));

  --shadow-sm:     0 1px 2px rgba(0,0,0,.4);
  --shadow-md:     0 8px 30px rgba(0,0,0,.35);
  --shadow-lg:     0 24px 70px rgba(0,0,0,.5);
  --glow:          0 0 0 1px rgba(34,211,238,.25), 0 12px 40px -12px rgba(34,211,238,.35);

  --r-sm: 8px; --r: 14px; --r-lg: 20px; --r-xl: 28px;
  --wrap: 1180px;
  --nav-h: 68px;

  --font: "Inter", -apple-system, BlinkMacSystemFont, "Segoe UI",
          "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", "Noto Sans SC", sans-serif;
  --mono: "JetBrains Mono", ui-monospace, SFMono-Regular, "SF Mono", Menlo, Consolas, monospace;
}

:root[data-theme="light"] {
  --bg:            #fbfcfe;
  --bg-alt:        #f3f6fb;
  --surface:       rgba(10,20,40,.028);
  --surface-2:     rgba(10,20,40,.05);
  --line:          rgba(10,25,55,.1);
  --line-strong:   rgba(10,25,55,.2);
  --text:          #0d1526;
  --text-2:        #4d5c72;
  --text-3:        #7b8798;

  --cyan:          #0891b2;
  --indigo:        #4f46e5;
  --teal:          #0d9488;
  --violet:        #7c3aed;
  --sky:           #0284c7;
  --amber:         #b45309;

  --grad:          linear-gradient(100deg, #0891b2 0%, #2563eb 45%, #7c3aed 100%);
  --grad-soft:     linear-gradient(100deg, rgba(8,145,178,.1), rgba(124,58,237,.1));

  --shadow-md:     0 8px 30px rgba(15,35,80,.08);
  --shadow-lg:     0 24px 70px rgba(15,35,80,.12);
  --glow:          0 0 0 1px rgba(8,145,178,.3), 0 12px 40px -14px rgba(8,145,178,.4);
}

/* ---------- reset ---------- */
*, *::before, *::after { box-sizing: border-box; }
html { -webkit-text-size-adjust: 100%; scroll-behavior: smooth; scroll-padding-top: calc(var(--nav-h) + 16px); }
@media (prefers-reduced-motion: reduce) { html { scroll-behavior: auto; } }
body {
  margin: 0;
  background: var(--bg);
  color: var(--text);
  font-family: var(--font);
  font-size: 16px;
  line-height: 1.65;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  overflow-x: hidden;
  transition: background-color .35s ease, color .35s ease;
}
img, svg { max-width: 100%; }
h1,h2,h3,h4 { margin: 0; line-height: 1.15; letter-spacing: -.022em; font-weight: 700; }
p { margin: 0; }
ul, ol, dl, dd { margin: 0; padding: 0; list-style: none; }
a { color: inherit; text-decoration: none; }
button { font: inherit; color: inherit; }
:focus-visible { outline: 2px solid var(--cyan); outline-offset: 3px; border-radius: 4px; }

.wrap { width: 100%; max-width: var(--wrap); margin-inline: auto; padding-inline: 24px; }
@media (max-width: 640px) { .wrap { padding-inline: 18px; } }

.skip {
  position: absolute; left: -9999px; top: 8px; z-index: 200;
  background: var(--text); color: var(--bg); padding: 10px 16px; border-radius: var(--r-sm);
}
.skip:focus { left: 16px; }

/* ---------- nav ---------- */
.nav {
  position: fixed; inset: 0 0 auto 0; z-index: 100;
  height: var(--nav-h);
  backdrop-filter: blur(14px) saturate(160%);
  -webkit-backdrop-filter: blur(14px) saturate(160%);
  border-bottom: 1px solid transparent;
  transition: background-color .3s ease, border-color .3s ease;
}
.nav.is-stuck {
  background: color-mix(in srgb, var(--bg) 78%, transparent);
  border-bottom-color: var(--line);
}
.nav-inner { height: var(--nav-h); display: flex; align-items: center; gap: 28px; }

.brand { display: inline-flex; align-items: center; gap: 10px; flex: none; }
.brand-mark { width: 26px; height: 26px; }
.brand-name { font-weight: 800; font-size: 17px; letter-spacing: -.03em; }
.brand-accent { background: var(--grad); -webkit-background-clip: text; background-clip: text; color: transparent; }

.nav-links { display: flex; gap: 4px; margin-left: 8px; }
.nav-links a {
  padding: 7px 13px; border-radius: 999px; font-size: 14.5px; font-weight: 500;
  color: var(--text-2); transition: color .2s, background-color .2s;
}
.nav-links a:hover { color: var(--text); background: var(--surface-2); }

.nav-actions { display: flex; align-items: center; gap: 10px; margin-left: auto; }

.icon-btn {
  display: grid; place-items: center; width: 36px; height: 36px; flex: none;
  border: 1px solid var(--line); border-radius: 10px; background: var(--surface);
  cursor: pointer; transition: border-color .2s, background-color .2s, transform .15s;
}
.icon-btn:hover { border-color: var(--line-strong); background: var(--surface-2); }
.icon-btn:active { transform: scale(.94); }
.icon-btn svg { width: 17px; height: 17px; fill: none; stroke: currentColor; stroke-width: 1.7; stroke-linecap: round; stroke-linejoin: round; }
.i-moon { display: none; }
:root[data-theme="light"] .i-sun { display: none; }
:root[data-theme="light"] .i-moon { display: block; }

.menu-btn { display: none; }

/* ---------- buttons ---------- */
.btn {
  display: inline-flex; align-items: center; justify-content: center; gap: 8px;
  padding: 10px 18px; border-radius: 999px; border: 1px solid transparent;
  font-size: 14.5px; font-weight: 600; letter-spacing: -.01em; white-space: nowrap;
  cursor: pointer; transition: transform .18s cubic-bezier(.34,1.4,.64,1), box-shadow .25s, background-color .2s, border-color .2s, opacity .2s;
}
.btn:hover { transform: translateY(-1.5px); }
.btn:active { transform: translateY(0); }
.btn-lg { padding: 13px 26px; font-size: 15.5px; }
.btn .arr { width: 16px; height: 16px; fill: none; stroke: currentColor; stroke-width: 2; stroke-linecap: round; stroke-linejoin: round; transition: transform .25s; }
.btn:hover .arr { transform: translateX(3px); }

.btn-primary {
  background: var(--grad); color: #05070c; font-weight: 700;
  box-shadow: 0 6px 24px -8px rgba(96,165,250,.6);
}
.btn-primary:hover { box-shadow: 0 12px 34px -10px rgba(96,165,250,.75); }
:root[data-theme="light"] .btn-primary { color: #fff; }

.btn-ghost { background: var(--surface); border-color: var(--line); color: var(--text); }
.btn-ghost:hover { border-color: var(--line-strong); background: var(--surface-2); }

/* ---------- mobile menu ---------- */
.mobile-menu {
  display: none; flex-direction: column; padding: 10px 24px 20px; gap: 2px;
  background: color-mix(in srgb, var(--bg) 96%, transparent);
  border-bottom: 1px solid var(--line);
  backdrop-filter: blur(14px); -webkit-backdrop-filter: blur(14px);
}
.mobile-menu a { padding: 12px 4px; font-size: 16px; font-weight: 500; color: var(--text-2); border-bottom: 1px solid var(--line); }
.mobile-menu a:last-child { border-bottom: none; }

@media (max-width: 900px) {
  .nav-links, .nav-only-lg { display: none; }
  .menu-btn { display: grid; }
  .mobile-menu:not([hidden]) { display: flex; }
}
@media (max-width: 480px) {
  .nav-actions .btn-primary { padding: 9px 14px; font-size: 13.5px; }
}

/* ---------- shared bits ---------- */
.eyebrow {
  display: inline-flex; align-items: center; gap: 8px;
  font-size: 13px; font-weight: 600; letter-spacing: .02em; color: var(--text-2);
  padding: 5px 14px 5px 10px; border: 1px solid var(--line); border-radius: 999px;
  background: var(--surface);
}
.eyebrow .dot {
  width: 6px; height: 6px; border-radius: 50%; background: var(--cyan);
  box-shadow: 0 0 0 3px color-mix(in srgb, var(--cyan) 20%, transparent);
  animation: pulse 2.4s ease-in-out infinite;
}
@keyframes pulse { 0%,100% { opacity: 1; } 50% { opacity: .35; } }

.grad { background: var(--grad); -webkit-background-clip: text; background-clip: text; color: transparent; }

.section { padding: 104px 0; position: relative; }
.section-alt { background: var(--bg-alt); border-block: 1px solid var(--line); }
@media (max-width: 720px) { .section { padding: 68px 0; } }

.sec-head { max-width: 700px; margin-bottom: 52px; }
.sec-head h2 { font-size: clamp(28px, 4vw, 42px); margin: 18px 0 0; }
.sec-sub { margin-top: 14px; color: var(--text-2); font-size: 17px; }

/* 窄屏交回自动折行，避免强制断点造成过短的行 */
.br-wide { display: none; }
@media (min-width: 560px) { .br-wide { display: inline; } }

/* 中文标题按语义均衡分行，避免出现「半小 / 时」这类孤字断行 */
.sec-head h2, .cta-inner h2, .card h3, .scen-card h3, .step h3 { text-wrap: balance; }
.sec-sub, .cta-inner > p, .card > p, .scen-card p, .step > p, .hero-sub { text-wrap: pretty; }

/* ---------- hero ---------- */
.hero { position: relative; padding: calc(var(--nav-h) + 92px) 0 96px; overflow: hidden; isolation: isolate; }
#edge-canvas { position: absolute; inset: 0; width: 100%; height: 100%; z-index: -2; opacity: .85; }
.hero-glow {
  position: absolute; z-index: -1; pointer-events: none;
  inset: -30% -10% auto -10%; height: 130%;
  background:
    radial-gradient(60% 50% at 22% 28%, rgba(34,211,238,.16), transparent 68%),
    radial-gradient(55% 45% at 78% 18%, rgba(129,140,248,.15), transparent 66%);
}
:root[data-theme="light"] .hero-glow {
  background:
    radial-gradient(60% 50% at 22% 28%, rgba(8,145,178,.12), transparent 68%),
    radial-gradient(55% 45% at 78% 18%, rgba(99,102,241,.11), transparent 66%);
}
.hero-fade {
  position: absolute; inset: auto 0 0 0; height: 180px; z-index: -1; pointer-events: none;
  background: linear-gradient(to bottom, transparent, var(--bg));
}
.hero-inner { position: relative; max-width: 880px; }
.hero-title { font-size: clamp(38px, 6.6vw, 74px); font-weight: 800; letter-spacing: -.04em; margin: 26px 0 0; }
.hero-sub { margin-top: 24px; max-width: 610px; font-size: clamp(16px, 2vw, 19px); color: var(--text-2); line-height: 1.7; }
.hero-cta { display: flex; flex-wrap: wrap; gap: 12px; margin-top: 36px; }

.stats {
  display: grid; grid-template-columns: repeat(4, minmax(0,1fr)); gap: 1px;
  margin-top: 72px; border: 1px solid var(--line); border-radius: var(--r-lg);
  background: var(--line); overflow: hidden;
}
.stat { background: color-mix(in srgb, var(--bg) 82%, transparent); padding: 22px 24px; backdrop-filter: blur(6px); }
.stat dt { font-size: 13px; color: var(--text-3); font-weight: 500; }
.stat dd { margin: 6px 0 0; font-size: clamp(24px, 3vw, 32px); font-weight: 700; letter-spacing: -.035em; font-variant-numeric: tabular-nums; }
.stat dd .num { background: var(--grad); -webkit-background-clip: text; background-clip: text; color: transparent; }
@media (max-width: 860px) { .stats { grid-template-columns: repeat(2, minmax(0,1fr)); margin-top: 52px; } }
@media (max-width: 400px) { .stats { grid-template-columns: 1fr; } }

/* ---------- trust ---------- */
.trust { padding: 46px 0; border-bottom: 1px solid var(--line); }
.trust-label { text-align: center; font-size: 12.5px; letter-spacing: .16em; text-transform: uppercase; color: var(--text-3); font-weight: 600; }
.trust-row {
  display: flex; flex-wrap: wrap; justify-content: center; gap: 14px 48px; margin-top: 26px;
}
.trust-row li {
  font-size: 17px; font-weight: 600; letter-spacing: -.01em; color: var(--text-3);
  opacity: .8; transition: color .25s, opacity .25s;
}
.trust-row li:hover { color: var(--text); opacity: 1; }

/* ---------- cards ---------- */
.grid { display: grid; gap: 20px; }
.cards { grid-template-columns: repeat(3, minmax(0,1fr)); }
@media (max-width: 980px) { .cards { grid-template-columns: repeat(2, minmax(0,1fr)); } }
@media (max-width: 640px) { .cards { grid-template-columns: 1fr; } }

.card {
  position: relative; padding: 28px 26px 26px; border-radius: var(--r-lg);
  border: 1px solid var(--line); background: var(--surface);
  transition: transform .3s cubic-bezier(.2,.7,.3,1), border-color .3s, box-shadow .3s, background-color .3s;
  overflow: hidden;
}
.card::before {
  content: ""; position: absolute; inset: 0; pointer-events: none; opacity: 0;
  background: radial-gradient(420px 220px at var(--mx,50%) var(--my,0%), rgba(34,211,238,.09), transparent 70%);
  transition: opacity .35s;
}
.card:hover { transform: translateY(-4px); border-color: var(--line-strong); box-shadow: var(--shadow-lg); background: var(--surface-2); }
.card:hover::before { opacity: 1; }
.card h3 { font-size: 19px; margin: 18px 0 10px; }
.card > p { color: var(--text-2); font-size: 15px; line-height: 1.7; }

.card-ico {
  width: 44px; height: 44px; display: grid; place-items: center; border-radius: 12px;
  border: 1px solid var(--line); background: var(--grad-soft);
}
.card-ico svg { width: 21px; height: 21px; fill: none; stroke: var(--cyan); stroke-width: 1.7; stroke-linecap: round; stroke-linejoin: round; }
.card-ico[data-tone="indigo"] svg { stroke: var(--indigo); }
.card-ico[data-tone="teal"]   svg { stroke: var(--teal); }
.card-ico[data-tone="violet"] svg { stroke: var(--violet); }
.card-ico[data-tone="sky"]    svg { stroke: var(--sky); }
.card-ico[data-tone="amber"]  svg { stroke: var(--amber); }

.card-list { margin-top: 18px; padding-top: 16px; border-top: 1px dashed var(--line); display: grid; gap: 9px; }
.card-list li { position: relative; padding-left: 20px; font-size: 13.8px; color: var(--text-3); }
.card-list li::before {
  content: ""; position: absolute; left: 2px; top: 9px; width: 7px; height: 7px;
  border-radius: 2px; background: var(--grad); opacity: .85;
}

/* ---------- architecture ---------- */
.arch {
  margin: 0; padding: 26px; border-radius: var(--r-xl);
  border: 1px solid var(--line); background: var(--surface); box-shadow: var(--shadow-md);
  overflow-x: auto;
}
.arch-svg { display: block; min-width: 880px; width: 100%; height: auto; }
.arch figcaption { margin-top: 20px; font-size: 13.5px; color: var(--text-3); text-align: center; }

.arch-lane rect { fill: color-mix(in srgb, var(--text) 3%, transparent); stroke: var(--line); stroke-width: 1; stroke-dasharray: 4 5; }
.arch-lane-label text { fill: var(--text-3); font-size: 12.5px; font-weight: 600; letter-spacing: .1em; text-anchor: middle; font-family: var(--font); }

.arch-node rect { fill: color-mix(in srgb, var(--bg) 90%, var(--text)); stroke: var(--line-strong); stroke-width: 1.1; }
.arch-node.accent rect { stroke: var(--cyan); fill: color-mix(in srgb, var(--cyan) 9%, var(--bg)); }
.arch-node.ghost rect { fill: none; stroke: var(--line); stroke-dasharray: 3 4; }
.arch-node .n-t { fill: var(--text); font-size: 13.5px; font-weight: 650; text-anchor: middle; font-family: var(--font); }
.arch-node .n-s { fill: var(--text-3); font-size: 11.5px; text-anchor: middle; font-family: var(--font); }

.arch-flow path { fill: none; stroke: currentColor; stroke-width: 1.8; stroke-linecap: round; stroke-linejoin: round; opacity: .85; }
.arch-flow path.thin { stroke-width: 1.2; opacity: .5; }
.arch-flow path.dash { stroke-dasharray: 5 5; }
.arch-flow path.dash-slow { stroke-dasharray: 3 5; opacity: .45; }
@media (prefers-reduced-motion: no-preference) {
  .arch-flow path.dash { animation: dashmove 1.4s linear infinite; }
  .arch-flow path.dash-slow { animation: dashmove 2.6s linear infinite; }
}
@keyframes dashmove { to { stroke-dashoffset: -20; } }

.arch-tag text { fill: var(--text-3); font-size: 11.5px; font-weight: 600; font-family: var(--font); }

/* ---------- steps ---------- */
.steps { display: grid; gap: 20px; grid-template-columns: repeat(3, minmax(0,1fr)); }
@media (max-width: 980px) { .steps { grid-template-columns: 1fr; } }

.step {
  position: relative; padding: 30px 26px; border-radius: var(--r-lg);
  border: 1px solid var(--line); background: var(--surface);
  display: flex; flex-direction: column;
  transition: border-color .3s, box-shadow .3s;
}
.step:hover { border-color: var(--line-strong); box-shadow: var(--shadow-md); }
.step-n {
  display: inline-block; font-family: var(--mono); font-size: 13px; font-weight: 500;
  letter-spacing: .08em; background: var(--grad); -webkit-background-clip: text; background-clip: text; color: transparent;
}
.step h3 { font-size: 20px; margin: 12px 0 10px; }
.step > p { color: var(--text-2); font-size: 15px; line-height: 1.7; flex: 1; }

.code {
  margin: 20px 0 0; padding: 16px 18px; border-radius: var(--r);
  background: color-mix(in srgb, #000 34%, var(--bg-alt));
  border: 1px solid var(--line); overflow-x: auto;
  font-family: var(--mono); font-size: 12.4px; line-height: 1.85; color: var(--text-2);
  -webkit-overflow-scrolling: touch;
}
:root[data-theme="light"] .code { background: #0e1420; color: #b6c2d4; border-color: transparent; }
.code code { white-space: pre; }
.c-c { color: #5f7186; font-style: italic; }
.c-k { color: #7dd3fc; }
.c-s { color: #86efac; }
.c-n { color: #fbbf24; }
.c-t { color: #c4b5fd; }

/* ---------- scenarios ---------- */
.scen { grid-template-columns: repeat(2, minmax(0,1fr)); }
@media (max-width: 780px) { .scen { grid-template-columns: 1fr; } }

.scen-card {
  padding: 30px 28px; border-radius: var(--r-lg);
  border: 1px solid var(--line); background: var(--surface);
  display: flex; flex-direction: column; gap: 12px;
  transition: transform .3s cubic-bezier(.2,.7,.3,1), border-color .3s, box-shadow .3s;
}
.scen-card:hover { transform: translateY(-3px); border-color: var(--line-strong); box-shadow: var(--shadow-lg); }
.scen-card h3 { font-size: 20px; }
.scen-card p { color: var(--text-2); font-size: 15px; line-height: 1.7; flex: 1; }
.scen-metric { display: flex; align-items: baseline; gap: 10px; margin-top: 6px; padding-top: 18px; border-top: 1px dashed var(--line); }
.scen-metric .num {
  font-size: 30px; font-weight: 750; letter-spacing: -.035em; font-variant-numeric: tabular-nums;
  background: var(--grad); -webkit-background-clip: text; background-clip: text; color: transparent;
}
.scen-metric small { font-size: 13px; color: var(--text-3); }

/* ---------- cta ---------- */
.cta { padding: 104px 0 112px; }
.cta-inner {
  position: relative; text-align: center; padding: 68px 32px 62px;
  border: 1px solid var(--line); border-radius: var(--r-xl);
  background: var(--bg-alt); overflow: hidden; isolation: isolate;
}
.cta-glow {
  position: absolute; inset: -60% -20% auto -20%; height: 200%; z-index: -1; pointer-events: none;
  background:
    radial-gradient(45% 42% at 50% 12%, rgba(34,211,238,.2), transparent 68%),
    radial-gradient(40% 38% at 78% 68%, rgba(167,139,250,.16), transparent 66%);
}
:root[data-theme="light"] .cta-glow {
  background:
    radial-gradient(45% 42% at 50% 12%, rgba(8,145,178,.13), transparent 68%),
    radial-gradient(40% 38% at 78% 68%, rgba(124,58,237,.11), transparent 66%);
}
.cta-inner h2 { font-size: clamp(26px, 4.2vw, 40px); max-width: 640px; margin-inline: auto; }
.cta-inner > p { margin: 18px auto 0; max-width: 540px; color: var(--text-2); font-size: 16.5px; }
.cta-actions { display: flex; flex-wrap: wrap; justify-content: center; gap: 12px; margin-top: 34px; }
.cta-note { margin-top: 24px; font-size: 13.5px; color: var(--text-3); }
@media (max-width: 640px) { .cta { padding: 68px 0 76px; } .cta-inner { padding: 46px 22px 44px; } }

/* ---------- footer ---------- */
.footer { border-top: 1px solid var(--line); background: var(--bg-alt); padding-top: 56px; }
.footer-inner { display: flex; flex-wrap: wrap; gap: 44px; justify-content: space-between; padding-bottom: 44px; }
.footer-brand { max-width: 320px; }
.footer-brand p { margin-top: 14px; font-size: 14px; color: var(--text-3); line-height: 1.7; }
.footer-links { display: flex; gap: 64px; }
.footer-links > div { display: flex; flex-direction: column; gap: 10px; }
.footer-links h4 { font-size: 12.5px; letter-spacing: .12em; text-transform: uppercase; color: var(--text-3); margin-bottom: 4px; font-weight: 600; }
.footer-links a { font-size: 14.5px; color: var(--text-2); transition: color .2s; }
.footer-links a:hover { color: var(--text); }
.footer-bottom {
  display: flex; flex-wrap: wrap; gap: 12px; justify-content: space-between;
  padding-block: 22px; border-top: 1px solid var(--line);
  font-size: 13px; color: var(--text-3);
}
@media (max-width: 640px) { .footer-links { gap: 40px; } }

/* ---------- reveal ----------
   渐进增强：只有脚本成功接管（html.js-reveal）才隐藏起始态。
   JS 未加载 / 报错 / 被禁用时，内容保持可见而不是永久 opacity:0。 */
.js-reveal .reveal { opacity: 0; transform: translateY(22px); transition: opacity .7s cubic-bezier(.2,.7,.3,1), transform .7s cubic-bezier(.2,.7,.3,1); }
.js-reveal .reveal.in { opacity: 1; transform: none; }
@media (prefers-reduced-motion: reduce) {
  .js-reveal .reveal { opacity: 1; transform: none; transition: none; }
  .eyebrow .dot { animation: none; }
  .btn:hover, .card:hover, .scen-card:hover { transform: none; }
}