:root {
  --ink: #07151d;
  --ink-2: #0d2731;
  --ink-3: #143a45;
  --cyan: #62f1e6;
  --cyan-soft: #b4fff8;
  --line: rgba(157, 235, 231, 0.22);
  --muted: #73949a;
  --paper: #edf9f6;
  --paper-2: #dbece9;
  --danger: #ff9f91;
  --radius: 18px;
  font-family: "Avenir Next", "Hiragino Sans", "Yu Gothic", sans-serif;
  color: var(--paper);
  background: var(--ink);
  font-synthesis: none;
}

* { box-sizing: border-box; }
html { scroll-behavior: smooth; }
body { margin: 0; min-width: 320px; background: var(--ink); color: var(--paper); }
button, input, select { font: inherit; }
button { cursor: pointer; }
.site-shell { max-width: 1440px; margin: 0 auto; padding: 0 5vw; overflow: hidden; }
.masthead { min-height: 82px; display: flex; align-items: center; justify-content: space-between; border-bottom: 1px solid var(--line); }
.brand { display: inline-flex; align-items: center; gap: 12px; color: var(--paper); text-decoration: none; font-size: 0.94rem; letter-spacing: .08em; font-weight: 700; }
.brand-mark { width: 27px; height: 27px; display: grid; grid-template-columns: repeat(2, 1fr); grid-template-rows: repeat(2, 1fr); gap: 3px; transform: rotate(45deg); }
.brand-mark i { display: block; border: 1px solid var(--cyan); background: rgba(98,241,230,.12); }
.brand-mark i:nth-child(2), .brand-mark i:nth-child(3) { background: var(--cyan); }
.eyebrow, .section-index, .panel-tag, .kicker { margin: 0; color: var(--cyan); font-size: .68rem; font-weight: 700; letter-spacing: .16em; }
.hero { min-height: 555px; padding: 78px 6.5vw 70px; position: relative; display: grid; grid-template-columns: 1.05fr .95fr; gap: 4vw; align-items: center; isolation: isolate; }
.blueprint-panel { border-bottom: 1px solid var(--line); background: linear-gradient(90deg, rgba(7,21,29,.98) 0%, rgba(7,21,29,.84) 45%, rgba(7,21,29,.52) 100%), url('/assets/network-blueprint.jpg') center / cover no-repeat; }
.blueprint-panel::after { content: ""; position: absolute; inset: 18px; border: 1px solid rgba(98,241,230,.17); pointer-events: none; z-index: -1; }
.hero-copy { max-width: 640px; }
.kicker { margin-bottom: 24px; }
h1, h2, h3, p { margin-top: 0; }
h1 { max-width: 650px; margin-bottom: 26px; font-size: clamp(3rem, 7vw, 6.8rem); line-height: .93; letter-spacing: -.07em; font-weight: 650; }
h1 em { color: var(--cyan); font-style: normal; }
.hero-lede { max-width: 560px; color: var(--cyan-soft); line-height: 1.9; font-size: .97rem; }
.hero-notes { display: flex; flex-wrap: wrap; gap: 18px 25px; margin-top: 38px; color: #9bc4c6; font-size: .75rem; letter-spacing: .04em; }
.hero-notes b { margin-right: 5px; color: var(--cyan); font-size: .68rem; }
.hero-diagram { min-height: 290px; display: grid; place-items: center; }
.diagram-frame { width: min(390px, 100%); aspect-ratio: 1.2; position: relative; border: 1px solid rgba(98,241,230,.44); background: rgba(8,27,35,.47); box-shadow: 20px 20px 0 rgba(98,241,230,.07), inset 0 0 0 11px rgba(98,241,230,.03); }
.diagram-frame::before, .diagram-frame::after { content: ""; position: absolute; background: var(--cyan); opacity: .55; }
.diagram-frame::before { width: 1px; height: 100%; left: 36%; top: 0; }
.diagram-frame::after { width: 100%; height: 1px; left: 0; top: 59%; }
.diagram-label { position: absolute; z-index: 2; color: var(--cyan-soft); font: 600 .56rem/1 monospace; letter-spacing: .12em; background: var(--ink-2); padding: 5px 7px; }
.label-a { left: 8%; top: 13%; }.label-b { right: 7%; bottom: 14%; }
.diagram-line { position: absolute; display: block; border-top: 1px dashed rgba(180,255,248,.75); transform-origin: left center; }
.line-a { width: 41%; left: 17%; top: 28%; transform: rotate(25deg); }.line-b { width: 45%; left: 47%; top: 70%; transform: rotate(-18deg); }
.diagram-node { position: absolute; width: 12px; height: 12px; border: 2px solid var(--cyan); background: var(--ink); transform: rotate(45deg); }
.node-a { top: 22%; left: 13%; }.node-b { top: 52%; left: 48%; background: var(--cyan); }.node-c { bottom: 17%; right: 13%; }
.workbench, .results, .comparison, .saved-section { padding: 80px 0 0; }
.section-heading { display: flex; align-items: end; justify-content: space-between; gap: 30px; margin-bottom: 27px; }
.section-heading h2 { margin: 9px 0 0; font-size: clamp(1.7rem, 3vw, 2.8rem); letter-spacing: -.055em; line-height: 1; }
.section-help { margin: 0 0 2px; color: var(--muted); font-size: .8rem; }
.text-button { display: inline-flex; min-width: 44px; min-height: 44px; align-items: center; justify-content: center; padding: 0 6px; border: 0; color: var(--cyan); background: none; text-decoration: underline; text-underline-offset: 4px; }
.input-board { display: grid; grid-template-columns: minmax(0, 1.7fr) minmax(170px, .8fr) auto; gap: 14px; padding: 22px; border: 1px solid var(--line); background: rgba(18, 52, 61, .42); }
.field-block { min-width: 0; }.field-block label { display: block; margin: 0 0 9px; color: var(--cyan-soft); font-size: .78rem; font-weight: 700; letter-spacing: .06em; }
.field-block input, .field-block select { width: 100%; min-height: 56px; border: 1px solid rgba(180,255,248,.28); border-radius: 0; outline: 0; padding: 0 16px; color: var(--paper); background: var(--ink-2); font-size: 1rem; }
.field-block input:focus, .field-block select:focus { border-color: var(--cyan); box-shadow: 0 0 0 3px rgba(98,241,230,.15); }
.field-hint { min-height: 30px; margin: 8px 0 0; color: var(--muted); font-size: .7rem; line-height: 1.5; }
.primary-button, .outline-button { display: inline-flex; min-height: 46px; align-items: center; justify-content: center; gap: 18px; border: 1px solid var(--cyan); padding: 0 19px; color: var(--ink); background: var(--cyan); font-weight: 800; letter-spacing: .04em; text-decoration: none; }
.primary-button { align-self: end; min-height: 56px; white-space: nowrap; }.primary-button:hover { background: var(--cyan-soft); }
.outline-button { color: var(--cyan); background: transparent; border-color: rgba(98,241,230,.48); min-height: 44px; font-size: .76rem; }.outline-button:hover { border-color: var(--cyan); background: rgba(98,241,230,.09); }
.status { min-height: 25px; padding: 12px 0 0; color: var(--muted); font-size: .78rem; }.status.success { color: var(--cyan); }.status.error { color: var(--danger); }
.result-actions { display: flex; gap: 8px; flex-wrap: wrap; justify-content: flex-end; }
.summary-grid { display: grid; grid-template-columns: repeat(4, minmax(0, 1fr)); gap: 10px; }
.summary-card { position: relative; min-height: 153px; padding: 18px; border: 1px solid var(--line); background: rgba(17,48,57,.52); overflow: hidden; }
.summary-card::before { content: ""; position: absolute; top: 0; left: 0; width: 33px; height: 2px; background: var(--line); }.summary-card.accent::before { width: 65px; background: var(--cyan); }
.summary-card.wide { grid-column: span 2; min-height: 135px; }.summary-card p { margin: 0 0 17px; color: var(--muted); font-size: .7rem; letter-spacing: .04em; }.summary-card strong { display: block; max-width: 100%; overflow-wrap: anywhere; color: var(--paper); font: 650 clamp(1.1rem, 2.2vw, 1.7rem)/1.25 ui-monospace, SFMono-Regular, Menlo, monospace; letter-spacing: -.05em; }.summary-card.accent strong { color: var(--cyan); }.summary-card span { display: block; margin-top: 12px; color: var(--muted); font-size: .68rem; }.copy-button { position: absolute; right: 13px; bottom: 13px; min-width: 44px; min-height: 44px; display: inline-flex; align-items: center; justify-content: center; border: 0; padding: 0; color: var(--cyan); background: transparent; font-size: .66rem; }
.analysis-grid { display: grid; grid-template-columns: 1.1fr .9fr; gap: 10px; margin-top: 10px; }.analysis-panel { min-height: 295px; padding: 25px; border: 1px solid var(--line); background: rgba(17,48,57,.35); }.panel-heading { display: flex; align-items: center; gap: 13px; }.panel-heading h3 { margin: 0; font-size: 1.05rem; letter-spacing: -.03em; }.panel-tag { font: 700 .63rem/1 monospace; white-space: nowrap; }.panel-note { min-height: 36px; margin: 28px 0 22px; color: var(--muted); font-size: .75rem; line-height: 1.6; }.panel-note b { color: var(--cyan-soft); font-family: ui-monospace, monospace; font-weight: 500; }.note-mark { margin-right: 4px; color: var(--cyan); }
.bit-map { position: relative; padding-top: 9px; overflow-x: auto; }.bit-cells { min-width: 430px; display: grid; grid-template-columns: repeat(32, 1fr); gap: 3px; }.bit { height: 38px; border: 1px solid rgba(98,241,230,.24); background: rgba(98,241,230,.05); }.bit.network { border-color: rgba(98,241,230,.62); background: rgba(98,241,230,.47); }.bit:nth-child(8n+1) { margin-left: 5px; }.octet-labels { min-width: 430px; display: grid; grid-template-columns: repeat(4, 1fr); margin-top: 8px; color: var(--muted); font: .65rem monospace; text-align: center; }.bit-boundary { min-width: 430px; position: relative; height: 28px; margin-top: 8px; border-top: 1px solid rgba(180,255,248,.2); }.bit-boundary::before { content: ""; position: absolute; top: -5px; left: var(--boundary); height: 11px; border-left: 1px solid var(--cyan); }.bit-boundary span { position: absolute; left: var(--boundary); transform: translateX(-50%); top: 8px; color: var(--cyan); font: .61rem monospace; white-space: nowrap; }.legend { display: flex; gap: 18px; margin-top: 13px; color: var(--muted); font-size: .67rem; }.legend span { display: inline-flex; align-items: center; gap: 6px; }.legend-swatch { width: 10px; height: 10px; display: inline-block; border: 1px solid rgba(98,241,230,.62); }.legend-swatch.network { background: rgba(98,241,230,.47); }.legend-swatch.host { background: rgba(98,241,230,.05); }
.use-case-notes { margin-top: 25px; }.use-case-row { display: grid; grid-template-columns: 32px 1fr; gap: 10px; padding: 14px 0; border-bottom: 1px solid var(--line); }.use-case-row > span { color: var(--cyan); font: .7rem monospace; }.use-case-row strong { font-size: .82rem; }.use-case-row p { margin: 6px 0 0; color: var(--muted); font-size: .75rem; line-height: 1.6; }.privacy-note { margin: 23px 0 0; color: var(--muted); font-size: .68rem; line-height: 1.6; }.privacy-note span { margin-right: 7px; color: var(--cyan); }
.split-preview { display: grid; grid-template-columns: repeat(4, minmax(0, 1fr)); gap: 10px; }.split-card { min-width: 0; padding: 17px; border: 1px solid var(--line); background: rgba(17,48,57,.32); transition: border-color .2s, background .2s; }.split-card.selected { border-color: var(--cyan); background: rgba(98,241,230,.09); }.split-card-top { display: flex; justify-content: space-between; align-items: center; }.split-number { color: var(--cyan); font: .72rem monospace; }.compare-check { min-height: 44px; display: inline-flex; align-items: center; gap: 6px; color: var(--muted); font-size: .68rem; }.compare-check input { accent-color: var(--cyan); width: 20px; height: 20px; }.split-cidr { margin: 22px 0 20px; color: var(--paper); font: 650 1.08rem monospace; letter-spacing: -.06em; overflow-wrap: anywhere; }.split-card dl { margin: 0; }.split-card dl > div { display: flex; justify-content: space-between; gap: 10px; padding: 8px 0; border-top: 1px solid var(--line); }.split-card dt { color: var(--muted); font-size: .65rem; }.split-card dd { margin: 0; color: var(--cyan-soft); font: .66rem monospace; text-align: right; overflow-wrap: anywhere; }.copy-row-button { width: 100%; min-height: 44px; display: flex; align-items: center; justify-content: space-between; margin-top: 18px; border: 0; border-top: 1px solid var(--line); padding: 14px 0 0; color: var(--cyan); background: transparent; text-align: left; font-size: .68rem; }.copy-row-button span { float: none; font-size: .88rem; }
.compare-panel { margin-top: 10px; padding: 24px; border: 1px solid var(--cyan); background: rgba(98,241,230,.06); }.compare-grid { display: grid; grid-template-columns: repeat(auto-fit, minmax(170px, 1fr)); gap: 10px; margin-top: 22px; }.compare-grid > div { padding: 14px; border-left: 2px solid var(--cyan); background: rgba(7,21,29,.5); }.compare-grid span { display: block; color: var(--cyan); font: .65rem monospace; }.compare-grid strong { display: block; margin-top: 8px; font: 650 .88rem monospace; }.compare-grid small { display: block; margin-top: 10px; color: var(--muted); font: .66rem monospace; overflow-wrap: anywhere; }
.saved-list { border-top: 1px solid var(--line); }.empty-state { margin: 0; padding: 24px 0; color: var(--muted); font-size: .78rem; }.saved-row { display: flex; justify-content: space-between; gap: 20px; align-items: center; padding: 16px 0; border-bottom: 1px solid var(--line); }.saved-row strong { display: block; color: var(--cyan-soft); font: .9rem monospace; }.saved-row span { display: block; margin-top: 4px; color: var(--muted); font-size: .68rem; }.saved-actions { display: flex; gap: 18px; }.danger { color: var(--danger); }
.footer { display: flex; justify-content: space-between; gap: 30px; align-items: end; margin-top: 110px; padding: 32px 0 44px; border-top: 1px solid var(--line); color: var(--muted); font-size: .7rem; line-height: 1.7; }.footer strong { color: var(--cyan-soft); }.footer-meta { font: .63rem monospace; letter-spacing: .08em; }
.not-found { min-height: 100vh; display: grid; place-content: center; gap: 16px; max-width: 650px; margin: auto; padding: 30px; }.not-found h1 { font-size: clamp(2.8rem, 8vw, 5rem); margin: 0; }.not-found p:not(.section-index) { color: var(--muted); }.link-button { width: fit-content; margin-top: 12px; }
@media (max-width: 900px) { .site-shell { padding: 0 4vw; }.hero { padding-inline: 4vw; grid-template-columns: 1fr; gap: 35px; }.hero-diagram { justify-self: start; width: min(450px, 100%); min-height: 220px; }.summary-grid { grid-template-columns: repeat(2, minmax(0, 1fr)); }.split-preview { grid-template-columns: repeat(2, minmax(0, 1fr)); }.input-board { grid-template-columns: 1fr 1fr; }.primary-button { grid-column: span 2; } }
@media (max-width: 600px) { .masthead { min-height: 70px; }.eyebrow { display: none; }.hero { min-height: 590px; padding-top: 55px; padding-bottom: 48px; }.hero h1 { font-size: clamp(3rem, 16vw, 5rem); }.hero-lede { font-size: .9rem; }.hero-notes { gap: 10px 16px; }.hero-diagram { min-height: 180px; }.diagram-frame { width: 88%; }.workbench, .results, .comparison, .saved-section { padding-top: 60px; }.section-heading, .result-heading { display: block; }.section-help { margin-top: 16px; }.result-actions { justify-content: flex-start; margin-top: 20px; }.input-board { grid-template-columns: 1fr; padding: 16px; }.primary-button { grid-column: auto; width: 100%; }.summary-grid { grid-template-columns: 1fr 1fr; gap: 7px; }.summary-card { min-height: 145px; padding: 14px; }.summary-card.wide { grid-column: span 2; min-height: 124px; }.summary-card strong { font-size: .94rem; }.summary-card p { margin-bottom: 12px; font-size: .64rem; }.analysis-grid { grid-template-columns: 1fr; }.analysis-panel { padding: 18px; }.split-preview { grid-template-columns: 1fr; }.saved-row { align-items: start; flex-direction: column; }.footer { display: block; margin-top: 80px; }.footer-meta { margin-top: 18px; } }
@media (max-width: 360px) { .site-shell { padding: 0 14px; }.hero { margin-inline: -14px; padding-inline: 28px; }.summary-grid { grid-template-columns: 1fr; }.summary-card.wide { grid-column: auto; }.summary-card { min-height: 126px; }.summary-card strong { font-size: 1.05rem; }.result-actions { display: grid; grid-template-columns: 1fr 1fr; }.outline-button { padding-inline: 8px; }.analysis-panel { min-height: 0; }.bit-cells, .octet-labels, .bit-boundary { min-width: 360px; }.bit { height: 32px; } }
@media print { :root { color: #111; background: #fff; }.site-shell { max-width: none; padding: 0; }.masthead, .hero, .workbench, .result-actions, .comparison, .saved-section, .footer, .copy-button, .copy-row-button, .compare-check { display: none !important; }.results { padding: 0; }.summary-card, .analysis-panel { color: #111; border-color: #999; background: #fff; }.summary-card p, .summary-card span, .panel-note, .use-case-row p, .legend, .privacy-note { color: #444; }.summary-card strong, .panel-heading h3 { color: #111 !important; }.analysis-grid { grid-template-columns: 1fr 1fr; }.bit.network { background: #bbb; border-color: #333; }.bit.host { border-color: #999; }.split-section { display: none; } }