:root {
  color-scheme: dark;
  --bg: #081018;
  --panel: #101b25;
  --line: #29404f;
  --text: #eaf2f6;
  --muted: #8ca4b3;
  --cyan: #31d5c8;
  --blue: #52a8ff;
  --amber: #ffbd59;
}

* { box-sizing: border-box; }
html { scroll-behavior: smooth; }
body {
  margin: 0;
  min-width: 320px;
  background:
    radial-gradient(circle at 15% -10%, rgba(49, 213, 200, .14), transparent 28rem),
    radial-gradient(circle at 100% 20%, rgba(82, 168, 255, .1), transparent 32rem),
    var(--bg);
  color: var(--text);
  font-family: Inter, "Segoe UI", Arial, sans-serif;
  line-height: 1.65;
}

a { color: var(--cyan); }
a:focus-visible { outline: 3px solid rgba(49, 213, 200, .38); outline-offset: 3px; }
.site-nav {
  width: min(1080px, 100%);
  margin: 0 auto;
  padding: 18px 22px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 20px;
}
.brand { color: var(--text); font-size: 1rem; font-weight: 900; letter-spacing: -.02em; text-decoration: none; }
.brand span { color: var(--cyan); }
.nav-links { display: flex; flex-wrap: wrap; justify-content: flex-end; gap: 8px; }
.nav-links a {
  padding: 7px 10px;
  border-radius: 999px;
  color: var(--muted);
  font-size: .78rem;
  font-weight: 750;
  text-decoration: none;
}
.nav-links a:hover, .nav-links a[aria-current="page"] { color: var(--text); background: rgba(49, 213, 200, .08); }
.page-shell { width: min(940px, calc(100% - 32px)); margin: 34px auto 70px; }
.eyebrow { color: var(--cyan); font-size: .72rem; font-weight: 900; letter-spacing: .12em; text-transform: uppercase; }
h1 { max-width: 19ch; margin: 10px 0 14px; font-size: clamp(2rem, 7vw, 4rem); line-height: 1.05; letter-spacing: -.055em; }
.lede { max-width: 70ch; margin: 0 0 28px; color: var(--muted); font-size: 1.02rem; }
.panel {
  margin-top: 16px;
  padding: clamp(20px, 5vw, 38px);
  border: 1px solid var(--line);
  border-radius: 18px;
  background: linear-gradient(155deg, rgba(21, 36, 49, .92), rgba(12, 22, 31, .96));
  box-shadow: 0 18px 50px rgba(0, 0, 0, .22);
}
.panel h2 { margin: 0 0 10px; font-size: 1.15rem; }
.panel p, .panel li { color: var(--muted); }
.panel p:last-child { margin-bottom: 0; }
.panel strong { color: var(--text); }
.note { border-left: 4px solid var(--amber); }
.equation {
  margin: 12px 0;
  padding: 14px;
  overflow-x: auto;
  border: 1px solid rgba(82, 168, 255, .28);
  border-radius: 11px;
  background: rgba(5, 12, 18, .58);
  color: #c6e3ff;
  font: .84rem/1.7 Consolas, "Segoe UI", sans-serif;
  white-space: pre-wrap;
}
.verification-badge { display: inline-block; padding: 5px 9px; border-radius: 999px; background: rgba(100, 227, 154, .12); color: #64e39a; font-size: .68rem; font-weight: 900; letter-spacing: .07em; }
.cta {
  display: inline-flex;
  margin-top: 24px;
  padding: 11px 16px;
  border-radius: 10px;
  background: var(--cyan);
  color: #061414;
  font-weight: 900;
  text-decoration: none;
}
.page-footer {
  width: min(940px, calc(100% - 32px));
  margin: 0 auto 28px;
  padding-top: 18px;
  border-top: 1px solid var(--line);
  color: var(--muted);
  font-size: .74rem;
}

/* Engineering guide */
.guide-shell { width: min(1180px, calc(100% - 32px)); }
.guide-shell h1 { max-width: 22ch; }
.guide-layout { display: grid; grid-template-columns: minmax(0, 1fr) 250px; gap: 22px; align-items: start; }
.guide-content { min-width: 0; }
.guide-toc {
  position: sticky;
  top: 16px;
  padding: 18px;
  border: 1px solid var(--line);
  border-radius: 16px;
  background: rgba(10, 19, 27, .94);
}
.guide-toc strong { display: block; margin-bottom: 9px; font-size: .8rem; text-transform: uppercase; letter-spacing: .08em; }
.guide-toc a { display: block; padding: 5px 0; color: var(--muted); font-size: .77rem; line-height: 1.35; text-decoration: none; }
.guide-toc a:hover { color: var(--cyan); }
.guide-section { scroll-margin-top: 18px; }
.guide-section > h2 { margin: 38px 0 12px; font-size: clamp(1.45rem, 4vw, 2.2rem); letter-spacing: -.035em; }
.guide-section > h3 { margin: 28px 0 8px; color: #dff9f6; }
.guide-grid { display: grid; grid-template-columns: repeat(2, minmax(0, 1fr)); gap: 14px; }
.guide-card { padding: 18px; border: 1px solid var(--line); border-radius: 14px; background: rgba(16, 27, 37, .74); }
.guide-card h3, .guide-card h4 { margin: 0 0 8px; }
.guide-card p, .guide-card li { color: var(--muted); }
.guide-card p:last-child { margin-bottom: 0; }
.tag { display: inline-block; margin: 0 5px 5px 0; padding: 4px 8px; border-radius: 999px; color: #bde9ff; background: rgba(82, 168, 255, .1); border: 1px solid rgba(82, 168, 255, .2); font-size: .68rem; font-weight: 850; }
.tag.warn { color: #ffd99c; background: rgba(255, 189, 89, .08); border-color: rgba(255, 189, 89, .24); }
.parameter-table { width: 100%; border-collapse: collapse; font-size: .8rem; }
.parameter-table th, .parameter-table td { padding: 10px 11px; border-bottom: 1px solid rgba(140, 164, 179, .16); text-align: left; vertical-align: top; }
.parameter-table th { color: #cfe7f2; background: rgba(82, 168, 255, .07); }
.parameter-table td { color: var(--muted); }
.parameter-table td:first-child { color: var(--text); font-family: Consolas, monospace; white-space: nowrap; }
.table-wrap { overflow-x: auto; border: 1px solid var(--line); border-radius: 14px; }
.math-stack { display: grid; gap: 8px; margin: 14px 0; }
.math-step { display: grid; grid-template-columns: 84px minmax(0, 1fr); gap: 10px; align-items: start; }
.math-label { padding-top: 11px; color: var(--muted); font-size: .68rem; font-weight: 900; letter-spacing: .08em; text-transform: uppercase; }
.math-step .equation { margin: 0; }
.answer { border-color: rgba(49, 213, 200, .42); color: #8df2e8; background: rgba(49, 213, 200, .06); font-weight: 800; }
.topology-block { margin: 20px 0; padding: clamp(18px, 4vw, 28px); border: 1px solid var(--line); border-radius: 18px; background: linear-gradient(150deg, rgba(20, 35, 47, .86), rgba(10, 19, 27, .94)); }
.topology-block h3 { margin: 0 0 4px; font-size: 1.35rem; }
.topology-meta { margin-bottom: 16px; color: var(--muted); font-size: .8rem; }
.detail-columns { display: grid; grid-template-columns: repeat(2, minmax(0, 1fr)); gap: 16px; }
.failure-list { margin: 10px 0 0; padding-left: 20px; }
.failure-list strong { color: #ffd99c; }
.figure { margin: 18px 0; padding: 18px; border: 1px solid rgba(82, 168, 255, .23); border-radius: 15px; background: #09131b; }
.figure figcaption { margin-top: 14px; color: var(--muted); font-size: .73rem; }
.figure-title { margin: 0 0 14px; color: #cfe7f2; font-size: .82rem; font-weight: 900; }
.power-flow { display: flex; align-items: stretch; justify-content: center; gap: 8px; overflow-x: auto; padding: 8px 0; }
.flow-node { display: grid; place-items: center; min-width: 112px; min-height: 64px; padding: 10px; border: 1px solid rgba(49, 213, 200, .38); border-radius: 11px; color: var(--text); background: rgba(49, 213, 200, .07); text-align: center; font-size: .76rem; font-weight: 800; }
.flow-node.switch { border-color: rgba(255, 189, 89, .45); background: rgba(255, 189, 89, .07); }
.flow-node.storage { border-color: rgba(82, 168, 255, .45); background: rgba(82, 168, 255, .08); }
.flow-arrow { display: grid; place-items: center; min-width: 28px; color: var(--cyan); font-size: 1.35rem; font-weight: 900; }
.loss-bars { display: grid; gap: 10px; }
.loss-row { display: grid; grid-template-columns: 120px minmax(120px, 1fr) 115px; gap: 10px; align-items: center; color: var(--muted); font-size: .75rem; }
.loss-track { height: 12px; overflow: hidden; border-radius: 999px; background: rgba(140, 164, 179, .1); }
.loss-fill { height: 100%; border-radius: inherit; background: linear-gradient(90deg, var(--cyan), var(--blue)); }
.failure-chain { display: grid; grid-template-columns: repeat(5, minmax(110px, 1fr)); gap: 8px; overflow-x: auto; }
.failure-node { position: relative; padding: 13px; border: 1px solid var(--line); border-radius: 11px; color: var(--muted); font-size: .73rem; }
.failure-node strong { display: block; margin-bottom: 4px; color: var(--text); }
.failure-node:not(:last-child)::after { content: "\2192"; position: absolute; right: -17px; top: 50%; z-index: 2; color: var(--amber); font-size: 1.15rem; transform: translateY(-50%); }
.source-list { padding-left: 20px; }
.source-list li { margin: 9px 0; }
.source-list a { overflow-wrap: anywhere; }
.source-kind { display: inline-block; min-width: 92px; color: #64e39a; font-size: .68rem; font-weight: 900; letter-spacing: .05em; text-transform: uppercase; }
.scope-note { padding: 14px 16px; border-left: 4px solid var(--cyan); background: rgba(49, 213, 200, .05); color: var(--muted); }
@media (max-width: 620px) {
  .site-nav { align-items: flex-start; flex-direction: column; }
  .nav-links { justify-content: flex-start; }
  .guide-layout { grid-template-columns: 1fr; }
  .guide-toc { position: static; order: -1; }
  .guide-grid, .detail-columns { grid-template-columns: 1fr; }
  .math-step { grid-template-columns: 1fr; gap: 2px; }
  .math-label { padding-top: 0; }
  .loss-row { grid-template-columns: 88px minmax(100px, 1fr); }
  .loss-row span:last-child { grid-column: 2; }
}

/* Product refinement layer */
:root {
  --bg: #071016;
  --panel: #0d1820;
  --line: #263b47;
  --text: #eef6f7;
  --muted: #94a8b2;
  --cyan: #42d6c7;
  --blue: #68aef5;
  --amber: #efb95d;
}
body {
  overflow-x: clip;
  background: radial-gradient(circle at 16% -16%, rgba(66, 214, 199, .1), transparent 31rem), var(--bg);
  font-family: Inter, ui-sans-serif, system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
  -webkit-font-smoothing: antialiased;
}
.skip-link {
  position: fixed;
  top: 8px;
  left: 10px;
  z-index: 100;
  padding: 10px 14px;
  border-radius: 8px;
  background: var(--text);
  color: var(--bg);
  font-weight: 850;
  text-decoration: none;
  transform: translateY(-150%);
  transition: transform .16s ease;
}
.skip-link:focus { transform: translateY(0); }
.site-nav {
  position: sticky;
  top: 0;
  z-index: 30;
  width: 100%;
  min-height: 54px;
  padding: 0 max(22px, calc((100vw - 1180px) / 2));
  border-bottom: 1px solid rgba(38, 59, 71, .82);
  background: rgba(7, 16, 22, .92);
  backdrop-filter: blur(16px);
}
.brand { font-size: .85rem; }
.nav-links { flex-wrap: nowrap; gap: 2px; }
.nav-links a {
  min-height: 54px;
  display: inline-flex;
  align-items: center;
  padding: 0 11px;
  border-radius: 0;
  border-bottom: 2px solid transparent;
  font-size: .75rem;
}
.nav-links a:hover { background: transparent; }
.nav-links a[aria-current="page"] { color: var(--text); border-bottom-color: var(--cyan); background: transparent; }
.page-shell { margin-top: clamp(38px, 6vw, 70px); }
h1 { margin-top: 12px; font-size: clamp(2.25rem, 7vw, 4.35rem); line-height: .98; }
.lede { font-size: 1.04rem; line-height: 1.7; }
.panel {
  border-radius: 12px;
  background: var(--panel);
  box-shadow: none;
}
.page-shell:not(.guide-shell) .panel { padding: clamp(22px, 5vw, 34px); }
.page-shell:not(.guide-shell) .panel + .panel { margin-top: 10px; }
.note { border-left-width: 3px; }
.cta {
  min-height: 46px;
  align-items: center;
  border-radius: 8px;
  transition: background-color .14s ease, transform .14s ease;
}
.cta:hover { background: #67e3d7; transform: translateY(-1px); }
.guide-layout { grid-template-columns: minmax(0, 1fr) 228px; gap: 36px; }
.guide-toc {
  top: 72px;
  border-radius: 10px;
  background: rgba(10, 19, 27, .96);
  box-shadow: none;
}
.guide-toc a { padding: 7px 0; }
.guide-section { scroll-margin-top: 74px; }
.guide-card,
.topology-block,
.figure,
.table-wrap { border-radius: 10px; }
.guide-grid { gap: 10px; }
.guide-card { background: rgba(13, 24, 32, .72); }
.topology-block { background: var(--panel); }
.equation { border-radius: 8px; }
.page-footer { margin-top: 40px; }
.tool-grid {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 10px;
  margin-top: 28px;
}
.tool-card {
  min-width: 0;
  padding: clamp(20px, 4vw, 28px);
  border: 1px solid var(--line);
  border-radius: 10px;
  background: var(--panel);
}
.tool-card > span { color: var(--cyan); font-size: .68rem; font-weight: 900; letter-spacing: .1em; }
.tool-card h2 { margin: 8px 0 9px; font-size: 1.18rem; letter-spacing: -.025em; }
.tool-card p { margin: 0 0 18px; color: var(--muted); }
.tool-card a { font-size: .82rem; font-weight: 850; text-decoration-thickness: 1px; text-underline-offset: 4px; }

@media (max-width: 760px) {
  .site-nav {
    min-height: auto;
    padding: 0;
    align-items: stretch;
    flex-direction: column;
    gap: 0;
  }
  .site-nav > .brand { min-height: 44px; display: flex; align-items: center; padding: 0 16px; border-bottom: 1px solid rgba(38, 59, 71, .5); }
  .nav-links {
    overflow-x: auto;
    justify-content: flex-start;
    padding: 0 5px;
    scrollbar-width: none;
    overscroll-behavior-x: contain;
  }
  .nav-links::-webkit-scrollbar { display: none; }
  .nav-links a { flex: 0 0 auto; min-height: 44px; padding: 0 11px; }
  .page-shell { width: min(100% - 24px, 940px); margin-top: 32px; }
  h1 { font-size: clamp(2.2rem, 12vw, 3.35rem); }
  .guide-layout { grid-template-columns: 1fr; gap: 18px; }
  .guide-toc { position: static; order: -1; }
  .guide-toc nav { display: grid; grid-template-columns: repeat(2, minmax(0, 1fr)); gap: 0 12px; }
  .guide-grid, .detail-columns { grid-template-columns: 1fr; }
  .tool-grid { grid-template-columns: 1fr; }
}

@media (max-width: 430px) {
  .guide-toc nav { grid-template-columns: 1fr; }
  .panel { padding: 20px; }
  .topology-block { margin-inline: -2px; padding: 18px 14px; }
}

@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  *, *::before, *::after { scroll-behavior: auto !important; transition-duration: .01ms !important; animation-duration: .01ms !important; animation-iteration-count: 1 !important; }
}