/* zachthomas.net: network-engineering look. Tokens first, then base, layout and components. */
@font-face { font-family: Inter; font-weight: 400; font-display: swap; src: url("../fonts/inter-latin-400-normal.da03732a27e1.woff2") format("woff2"); }
@font-face { font-family: Inter; font-weight: 500; font-display: swap; src: url("../fonts/inter-latin-500-normal.51205681a1ba.woff2") format("woff2"); }
@font-face { font-family: Inter; font-weight: 600; font-display: swap; src: url("../fonts/inter-latin-600-normal.2ede57db1a3a.woff2") format("woff2"); }
@font-face { font-family: "JetBrains Mono"; font-weight: 500; font-display: swap; src: url("../fonts/jetbrains-mono-latin-500-normal.a21e038a03f7.woff2") format("woff2"); }
@font-face { font-family: "JetBrains Mono"; font-weight: 600; font-display: swap; src: url("../fonts/jetbrains-mono-latin-600-normal.075ec35bc15b.woff2") format("woff2"); }
@font-face { font-family: "JetBrains Mono"; font-weight: 700; font-display: swap; src: url("../fonts/jetbrains-mono-latin-700-normal.69002db50656.woff2") format("woff2"); }

:root {
  --base: #f6f9fc; --surface: #e8eff6; --line: #cfdbe7; --ink: #0f2a47; --muted: #4a5f75;
  --navy: #0f2a47; --blue: #215b9d; --green: #1b7e5a; --sky: #3a9bd5; --on-blue: #ffffff;
  --sans: Inter, system-ui, -apple-system, "Segoe UI", Roboto, sans-serif;
  --mono: "JetBrains Mono", ui-monospace, SFMono-Regular, Menlo, Consolas, monospace;
  --wide: 1120px; --narrow: 720px; --gutter: 1.5rem;
}
:root[data-theme="dark"] {
  --base: #0b1622; --surface: #12263a; --line: #24415c; --ink: #e8f0f8; --muted: #9db3c8;
  --navy: #1f4f80; --blue: #6aa8e6; --green: #4cc59a; --sky: #7cc4f0; --on-blue: #0b1622;
  color-scheme: dark;
}
@media (prefers-color-scheme: dark) {
  :root:not([data-theme="light"]) {
    --base: #0b1622; --surface: #12263a; --line: #24415c; --ink: #e8f0f8; --muted: #9db3c8;
    --navy: #1f4f80; --blue: #6aa8e6; --green: #4cc59a; --sky: #7cc4f0; --on-blue: #0b1622;
    color-scheme: dark;
  }
}

*, *::before, *::after { box-sizing: border-box; }
html { scroll-behavior: smooth; }
body { margin: 0; background: var(--base); color: var(--ink); font: 400 1rem/1.65 var(--sans); -webkit-font-smoothing: antialiased; }
img { max-width: 100%; height: auto; border-radius: 8px; }
a { color: var(--blue); text-underline-offset: 3px; }
a:hover { text-decoration: none; }
:where(a, button):focus-visible { outline: 3px solid var(--blue); outline-offset: 2px; }
.skip { position: absolute; left: -999px; top: 0; background: var(--ink); color: var(--base); padding: 0.5rem 1rem; z-index: 10; }
.skip:focus { left: 0; }
h1, h2, h3, h4 { font-family: var(--mono); font-weight: 600; line-height: 1.2; margin: 0 0 0.75rem; text-wrap: balance; }
h1 { font-size: clamp(2rem, 5vw, 2.75rem); font-weight: 700; letter-spacing: -0.02em; }
h2 { font-size: clamp(1.625rem, 4vw, 2rem); }
h3 { font-size: clamp(1.125rem, 3vw, 1.25rem); }
p { margin: 0 0 1rem; }
.muted { color: var(--muted); }
.inner { max-width: var(--wide); margin: 0 auto; padding-inline: var(--gutter); }
.inner.narrow { max-width: var(--narrow); }
.zt-eyebrow { font: 500 0.75rem var(--mono); letter-spacing: 0.08em; text-transform: uppercase; color: var(--muted); margin: 0 0 0.5rem; }

/* Header and footer */
.zt-header { border-bottom: 1px solid var(--line); padding: 0.75rem 0; }
.zt-header .inner { display: flex; align-items: center; justify-content: space-between; gap: 1rem; flex-wrap: wrap; }
.zt-brand { display: inline-flex; align-items: center; gap: 0.75rem; text-decoration: none; color: var(--ink); }
.zt-site-title { font: 700 1.125rem var(--mono); letter-spacing: -0.01em; }
.zt-mark { display: inline-flex; line-height: 0; }
.zt-mark svg { width: 40px; height: 40px; display: block; }
.zt-header-end { display: flex; align-items: center; gap: 1rem; flex-wrap: wrap; }
.zt-nav { display: flex; flex-wrap: wrap; gap: 0.25rem 1.5rem; font: 500 0.75rem var(--mono); letter-spacing: 0.08em; text-transform: uppercase; }
.zt-nav a { color: var(--muted); text-decoration: none; padding: 0.625rem 0; display: inline-block; }
.zt-nav a:hover { color: var(--blue); }
.zt-theme-toggle { display: inline-flex; align-items: center; justify-content: center; min-width: 44px; min-height: 44px; padding: 0; border: 1px solid var(--line); border-radius: 8px; background: transparent; color: var(--ink); cursor: pointer; }
.zt-theme-toggle:hover { border-color: var(--blue); color: var(--blue); }
.zt-theme-toggle svg { width: 20px; height: 20px; }
.zt-theme-toggle .zt-icon-sun { display: none; }
:root[data-theme="dark"] .zt-theme-toggle .zt-icon-sun { display: block; }
:root[data-theme="dark"] .zt-theme-toggle .zt-icon-moon { display: none; }
.zt-footer { background: var(--navy); color: #e8f0f8; padding: 2.5rem 0; margin-top: 4rem; }
.zt-footer .inner { display: flex; flex-wrap: wrap; align-items: center; justify-content: space-between; gap: 1.5rem; }
.zt-footer .zt-brand, .zt-footer .zt-nav a { color: #e8f0f8; }
.zt-footer .zt-copy { font-size: 0.875rem; color: #c4d4e4; margin: 0; }

/* Buttons */
.zt-buttons { display: flex; flex-wrap: wrap; gap: 0.75rem; margin-top: 1.5rem; }
.btn { display: inline-block; padding: 0.875rem 1.5rem; border: 2px solid var(--blue); border-radius: 8px; background: var(--blue); color: var(--on-blue); font: 700 0.8125rem var(--mono); letter-spacing: 0.04em; text-decoration: none; }
.btn:hover { background: var(--ink); border-color: var(--ink); color: var(--base); }
.btn--outline { background: transparent; color: var(--blue); }

/* Hero */
.zt-hero { background-color: var(--navy); color: #e8f0f8; padding: clamp(3rem, 8vw, 6rem) 0;
  background-image: linear-gradient(rgba(124,196,240,.07) 1px, transparent 1px), linear-gradient(90deg, rgba(124,196,240,.07) 1px, transparent 1px); background-size: 32px 32px; }
.hero-grid { display: grid; grid-template-columns: 1.25fr 1fr; gap: 2.5rem; align-items: center; }
.zt-hero h1 { font-size: clamp(2.75rem, 8vw, 4.5rem); line-height: 1; margin: 0; color: #e8f0f8; }
.zt-hero .zt-eyebrow { color: #7cc4f0; }
.zt-title { font: 500 clamp(1.125rem, 3vw, 1.25rem)/1.4 var(--mono); margin: 0.5rem 0 0.9rem; }
.zt-lede { color: #c4d4e4; font-size: 1.125rem; line-height: 1.6; max-width: 34rem; }
.zt-hero .btn { background: #7cc4f0; border-color: #7cc4f0; color: #0f2a47; }
.zt-hero .btn:hover { background: #e8f0f8; border-color: #e8f0f8; }
.zt-hero .btn--outline { background: transparent; border-color: #e8f0f8; color: #e8f0f8; }
.zt-hero .btn--outline:hover { background: #e8f0f8; color: #0f2a47; }
@media (max-width: 781px) { .hero-grid { grid-template-columns: 1fr; } }

/* Status LEDs */
.zt-led { display: inline-flex; align-items: center; gap: 0.5rem; font: 500 0.75rem/1.3 var(--mono); letter-spacing: 0.04em; }
.zt-led::before { content: ""; flex: none; width: 0.5rem; height: 0.5rem; border-radius: 50%; background: var(--led, #4cc59a);
  box-shadow: 0 0 0 3px color-mix(in srgb, var(--led, #4cc59a) 25%, transparent), 0 0 8px var(--led, #4cc59a); animation: zt-led 2.4s ease-in-out infinite; }
.zt-led--green { --led: #4cc59a; } .zt-led--sky { --led: #7cc4f0; } .zt-led--amber { --led: #f2b84b; }
.zt-led--amber::before { animation-duration: 1.6s; }
.zt-status { list-style: none; display: flex; flex-wrap: wrap; gap: 0.625rem 1.5rem; margin: 1.5rem 0 0; padding: 1.25rem 0 0; border-top: 1px solid rgba(124,196,240,.25); }
.zt-status .zt-led { color: #c4d4e4; }
.zt-status-line { margin: auto 0 0; padding-top: 0.5rem; }
.zt-status-line .zt-led { color: var(--muted); }
@keyframes zt-led { 0%, 100% { opacity: 1; } 50% { opacity: .45; } }

/* Topology */
.zt-hero-art { background: rgba(11,22,34,.55); border: 1px solid rgba(124,196,240,.3); border-radius: 10px; overflow: hidden; max-width: 420px; margin-left: auto; }
.zt-hero-art__bar { padding: 0.625rem 0.875rem; border-bottom: 1px solid rgba(124,196,240,.25); font: 400 0.8125rem var(--mono); color: #c4d4e4; }
.zt-hero-art .g { color: #4cc59a; } .zt-hero-art .b { color: #7cc4f0; }
.zt-cursor { display: inline-block; width: .5em; height: 1em; margin-left: 2px; vertical-align: text-bottom; background: #e8f0f8; animation: zt-blink 1.1s steps(1) infinite; }
@keyframes zt-blink { 50% { opacity: 0; } }
.zt-hero-art svg { display: block; width: 100%; height: auto; padding: .5rem; }
.zt-hero-art .lk { stroke: #7cc4f0; stroke-opacity: .45; stroke-width: 2; }
.zt-hero-art .lk--x { stroke-dasharray: 3 5; stroke-opacity: .3; }
.zt-hero-art .pk { stroke: #4cc59a; stroke-width: 3.5; stroke-dasharray: 5 95; filter: drop-shadow(0 0 3px #4cc59a); animation: zt-packet 2.6s linear infinite; }
.zt-hero-art .pk--b { animation-delay: -.5s; } .zt-hero-art .pk--c { animation-delay: -1.1s; }
.zt-hero-art .pk--d { animation-delay: -1.6s; stroke: #7cc4f0; } .zt-hero-art .pk--e { animation-delay: -.9s; stroke: #7cc4f0; } .zt-hero-art .pk--f { animation-delay: -2.1s; stroke: #7cc4f0; }
@keyframes zt-packet { from { stroke-dashoffset: 100; } to { stroke-dashoffset: 0; } }
.zt-hero-art .n { stroke-width: 2; }
.zt-hero-art .n--wan { fill: #12263a; stroke: #7cc4f0; } .zt-hero-art .n--core { fill: #4cc59a; stroke: #e8f0f8; }
.zt-hero-art .n--dist { fill: #7cc4f0; stroke: #e8f0f8; } .zt-hero-art .n--acc { fill: #12263a; stroke: #7cc4f0; }
.zt-hero-art .n--warn { stroke: #f2b84b; animation: zt-warn 1.6s ease-in-out infinite; }
@keyframes zt-warn { 0%, 100% { fill: #12263a; } 50% { fill: #f2b84b; } }
.zt-hero-art .t { font: 600 10px var(--mono); letter-spacing: .06em; fill: #9db3c8; }
.zt-hero-art .t--wan { fill: #7cc4f0; }
@media (max-width: 781px) { .zt-hero-art { margin-left: 0; max-width: none; } }
@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  .zt-hero-art .pk, .zt-hero-art .n--warn, .zt-led::before, .zt-cursor { animation: none; }
  .zt-hero-art .pk { stroke-dasharray: 5 20; }
}

/* Sections, bands, cards */
.zt-section { padding: clamp(3rem, 8vw, 6rem) 0 3rem; }
.zt-section--tight { padding-top: 0; }
.zt-band { background: var(--surface); border-block: 1px solid var(--line); padding: 4rem 0; }
.band-grid { display: grid; grid-template-columns: 1.7fr 1fr; gap: 2rem; align-items: center; }
.band-grid .zt-buttons { margin: 0; justify-content: flex-end; }
.zt-band p { color: var(--muted); max-width: 36rem; }
.zt-academy { border-left: 4px solid var(--green); }
@media (max-width: 781px) { .band-grid { grid-template-columns: 1fr; } .band-grid .zt-buttons { justify-content: flex-start; } }
.zt-cards { display: grid; grid-template-columns: repeat(auto-fit, minmax(260px, 1fr)); gap: 1.5rem; margin-top: 2rem; }
.zt-card { background: var(--surface); border: 1px solid var(--line); border-radius: 8px; padding: 1.75rem; display: flex; flex-direction: column; gap: 0.75rem; }
.zt-card > * { margin: 0; }
.zt-tag { font: 500 0.75rem var(--mono); letter-spacing: .08em; text-transform: uppercase; color: var(--blue); }
.zt-card h3 a { color: var(--ink); text-decoration: none; } .zt-card h3 a:hover { color: var(--blue); }
.zt-card-body { font-size: .9375rem; line-height: 1.6; color: var(--muted); }
.zt-link { margin-top: auto !important; padding-top: .5rem; font: 500 .8125rem var(--mono); }
.zt-link a { display: inline-block; padding: .5rem 0; text-decoration: none; }
.zt-link a:hover { text-decoration: underline; }
.zt-rack .zt-card { border-left: 4px solid var(--blue); } .zt-rack .zt-card:hover { border-left-color: var(--green); }
.zt-more { margin-top: 1.5rem; padding-top: 1.25rem; border-top: 1px dashed var(--line); font: 400 .875rem var(--mono); color: var(--muted); }

/* About + terminal */
.zt-about { padding: 3rem 0 6rem; }
.about-grid { display: grid; grid-template-columns: 1fr 1fr; gap: 3rem; align-items: center; }
@media (max-width: 781px) { .about-grid { grid-template-columns: 1fr; } }
.zt-terminal { background: var(--navy); color: #e8f0f8; border-radius: 8px; padding: 1.75rem; font: 400 .875rem/1.7 var(--mono); }
.zt-terminal .gap { margin-top: .75rem; } .zt-terminal .p, .zt-terminal .ok { color: #4cc59a; } .zt-terminal .d { color: #7cc4f0; } .zt-terminal .o { color: #c4d4e4; }

/* Articles and markdown */
.zt-article { padding: 3rem 0 2rem; }
.prose { overflow-wrap: break-word; }
.prose > :last-child { margin-bottom: 0; }
.prose h2 { margin-top: 2.25rem; } .prose h3 { margin-top: 1.75rem; }
.prose pre { background: var(--surface); border: 1px solid var(--line); border-radius: 8px; padding: 1.25rem; overflow-x: auto; font: 400 .875rem/1.6 var(--mono); }
.prose code { font-family: var(--mono); font-size: .9em; background: var(--surface); padding: .1em .35em; border-radius: 4px; }
.prose pre code { background: none; padding: 0; }
.prose blockquote { background: var(--surface); border-radius: 8px; margin: 1.5rem 0; padding: 1rem 1.5rem; }
.prose blockquote > :last-child { margin-bottom: 0; }
.prose table { width: 100%; border-collapse: collapse; display: block; overflow-x: auto; }
.prose th, .prose td { border: 1px solid var(--line); padding: .5rem .75rem; text-align: left; }
.prose hr { border: 0; border-top: 1px solid var(--line); margin: 2rem 0; }
.zt-post-list { list-style: none; margin: 2rem 0 0; padding: 0; display: grid; gap: 2rem; }
.zt-post-list li { border-bottom: 1px solid var(--line); padding-bottom: 2rem; }
.zt-post-list h2, .zt-post-list h3 { margin: .25rem 0 .5rem; font-size: 1.375rem; }
.zt-post-list h2 a, .zt-post-list h3 a { color: var(--ink); text-decoration: none; }
.zt-post-list h2 a:hover, .zt-post-list h3 a:hover { color: var(--blue); }
.zt-date { font: 500 .75rem var(--mono); letter-spacing: .08em; text-transform: uppercase; color: var(--muted); margin: 0; }
.zt-tags { display: flex; flex-wrap: wrap; gap: .5rem; margin: .5rem 0 1rem; }
.zt-tags a { font: 500 .75rem var(--mono); border: 1px solid var(--line); border-radius: 99px; padding: .125rem .625rem; text-decoration: none; color: var(--muted); }
.zt-tags a:hover { border-color: var(--blue); color: var(--blue); }

@media print { .zt-header, .zt-footer, .zt-theme-toggle { display: none !important; } body { background: #fff; color: #000; } }

/* Contact form */
.zt-form label { display: block; font: 500 0.75rem var(--mono); letter-spacing: 0.08em; text-transform: uppercase; color: var(--muted); margin-bottom: 0.35rem; }
.zt-form input, .zt-form textarea { width: 100%; box-sizing: border-box; padding: 0.7rem 0.85rem; font: inherit; color: var(--ink); background: var(--surface); border: 1px solid var(--line); border-radius: 8px; }
.zt-form input:focus-visible, .zt-form textarea:focus-visible { outline: 3px solid var(--blue); outline-offset: 2px; }
.zt-form button { cursor: pointer; }
.zt-error { display: block; color: #b3261e; font-size: 0.875rem; margin-top: 0.25rem; }
:root[data-theme="dark"] .zt-error { color: #ff8a80; }
.zt-notice { padding: 1rem 1.25rem; border: 1px solid var(--green); border-radius: 8px; background: var(--surface); }
.zt-hp { position: absolute; left: -9999px; width: 1px; height: 1px; overflow: hidden; }

/* About headshot */
.zt-avatar { display: block; width: 144px; height: 144px; border-radius: 50%; margin: 0 0 1.25rem; }