:root {
  --ink: #11130f;
  --paper: #e9e4d6;
  --paper-deep: #d8d1bd;
  --signal: #ff5c35;
  --signal-bright: #ffca3a;
  --mint: #a8ff78;
  --blue: #73d7ff;
  --muted: #6d7066;
  --line: rgba(17, 19, 15, .22);
  --terminal: #0c110d;
  --display: "Bahnschrift Condensed", "Arial Narrow", sans-serif;
  --body: "Noto Sans TC", "Microsoft JhengHei", sans-serif;
  --mono: "Cascadia Code", "IBM Plex Mono", Consolas, monospace;
}

* { box-sizing: border-box; }
html { scroll-behavior: smooth; }
body {
  margin: 0;
  color: var(--ink);
  background: var(--paper);
  font-family: var(--body);
  line-height: 1.65;
}
button, input, select, textarea { font: inherit; }
button { cursor: pointer; }
.skip-link { position: fixed; top: -100px; left: 16px; z-index: 100; padding: 10px 14px; color: white; background: var(--ink); }
.skip-link:focus { top: 12px; }
.grain { position: fixed; inset: 0; z-index: 50; opacity: .055; pointer-events: none; background-image: url("data:image/svg+xml,%3Csvg viewBox='0 0 180 180' xmlns='http://www.w3.org/2000/svg'%3E%3Cfilter id='n'%3E%3CfeTurbulence type='fractalNoise' baseFrequency='.72' numOctaves='3' stitchTiles='stitch'/%3E%3C/filter%3E%3Crect width='100%25' height='100%25' filter='url(%23n)'/%3E%3C/svg%3E"); }

.masthead { height: 92px; display: flex; align-items: center; justify-content: space-between; padding: 0 3vw; border-bottom: 1px solid var(--line); background: rgba(233,228,214,.92); position: sticky; top: 0; z-index: 40; backdrop-filter: blur(16px); }
.brand-lockup { display: flex; align-items: center; gap: 14px; }
.brand-mark { width: 52px; height: 52px; display: grid; place-items: center; border: 1px solid var(--ink); border-radius: 50%; }
.brand-mark svg { width: 36px; fill: none; stroke: currentColor; stroke-width: 2; }
.brand-mark circle { fill: var(--signal); stroke: none; }
.eyebrow, .kicker { margin: 0; font: 700 .7rem/1.2 var(--mono); letter-spacing: .18em; text-transform: uppercase; }
.brand-lockup h1 { margin: 2px 0 0; font: 800 1.45rem/1 var(--display); letter-spacing: .04em; }
.mast-status { display: flex; align-items: center; gap: 10px; font: 700 .75rem var(--mono); }
.mast-status strong { margin-left: 12px; padding-left: 18px; border-left: 1px solid var(--line); }
.status-dot { width: 8px; height: 8px; border-radius: 50%; background: #3ddc84; box-shadow: 0 0 0 5px rgba(61,220,132,.16); }

.app-shell { display: grid; grid-template-columns: 270px minmax(0,1fr); max-width: 1680px; margin: 0 auto; }
.course-rail { min-height: calc(100vh - 92px); padding: 30px 20px; border-right: 1px solid var(--line); position: sticky; top: 92px; align-self: start; max-height: calc(100vh - 92px); overflow: auto; }
.rail-intro { display: flex; justify-content: space-between; align-items: center; margin-bottom: 18px; font: 700 .7rem var(--mono); letter-spacing: .12em; }
.text-button { padding: 0; border: 0; border-bottom: 1px solid currentColor; background: none; font: 600 .68rem var(--mono); color: var(--muted); }
.lesson-nav-button { width: 100%; display: grid; grid-template-columns: 34px 1fr 16px; align-items: center; gap: 9px; text-align: left; border: 0; border-top: 1px solid var(--line); padding: 13px 5px; background: transparent; color: var(--muted); transition: color .2s, transform .2s; }
.lesson-nav-button:last-child { border-bottom: 1px solid var(--line); }
.lesson-nav-button:hover { color: var(--ink); transform: translateX(3px); }
.lesson-nav-button.active { color: var(--ink); }
.lesson-nav-button .nav-index { font: 800 1.25rem var(--display); }
.lesson-nav-button .nav-title { font-weight: 700; font-size: .85rem; line-height: 1.25; }
.lesson-nav-button .nav-check { width: 13px; height: 13px; border: 1px solid currentColor; border-radius: 50%; }
.lesson-nav-button.done .nav-check { background: var(--signal); border-color: var(--signal); box-shadow: inset 0 0 0 3px var(--paper); }
.rail-note { margin-top: 30px; padding: 18px; background: var(--ink); color: var(--paper); transform: rotate(-1.2deg); }
.rail-note-index { color: var(--signal-bright); font: 700 .7rem var(--mono); letter-spacing: .12em; }
.rail-note p { margin: 8px 0 0; font-size: .84rem; }

main { min-width: 0; }
.hero-panel { min-height: 650px; display: grid; grid-template-columns: .9fr 1.1fr; overflow: hidden; border-bottom: 1px solid var(--line); }
.hero-copy { padding: clamp(56px,8vw,120px) clamp(34px,6vw,100px); position: relative; z-index: 2; }
.hero-copy h2 { margin: 24px 0; max-width: 720px; font: 900 clamp(3.8rem,7.7vw,8rem)/.82 var(--display); letter-spacing: -.035em; text-transform: uppercase; }
.hero-copy h2 em { color: var(--signal); font-style: normal; }
.hero-lede { max-width: 600px; font-size: 1.05rem; }
.hero-actions { display: flex; gap: 12px; margin-top: 35px; flex-wrap: wrap; }
.primary-button, .secondary-button { border: 1px solid var(--ink); padding: 12px 18px; font: 800 .78rem var(--mono); letter-spacing: .04em; transition: transform .18s, box-shadow .18s, background .18s; }
.primary-button { background: var(--signal); color: var(--ink); box-shadow: 5px 5px 0 var(--ink); }
.secondary-button { background: transparent; color: var(--ink); }
.primary-button:hover, .secondary-button:hover { transform: translate(-2px,-2px); box-shadow: 7px 7px 0 var(--ink); }
.primary-button:active, .secondary-button:active { transform: translate(2px,2px); box-shadow: 2px 2px 0 var(--ink); }
.primary-button.full { width: 100%; margin-top: 8px; }

.radio-stage { min-height: 600px; position: relative; background: var(--ink); color: var(--paper); overflow: hidden; }
.frequency-grid { position: absolute; inset: 0; opacity: .22; background-image: linear-gradient(rgba(168,255,120,.25) 1px, transparent 1px), linear-gradient(90deg, rgba(168,255,120,.25) 1px, transparent 1px); background-size: 38px 38px; transform: perspective(450px) rotateX(54deg) scale(1.5); transform-origin: bottom; }
.radio-stage::before { content: "2.4 GHz"; position: absolute; right: -14px; top: 20px; font: 900 clamp(5rem,10vw,10rem)/1 var(--display); color: rgba(233,228,214,.055); writing-mode: vertical-rl; }
.radio-node { position: absolute; width: 185px; padding: 19px; border: 1px solid rgba(233,228,214,.55); background: rgba(17,19,15,.85); box-shadow: 9px 9px 0 var(--signal); z-index: 3; }
.node-a { left: 9%; top: 22%; }
.node-b { right: 9%; top: 52%; box-shadow: 9px 9px 0 var(--mint); }
.radio-node small { display: block; color: var(--signal-bright); font: 700 .67rem var(--mono); letter-spacing: .15em; }
.radio-node strong { display: block; margin: 8px 0 3px; font: 700 1.1rem var(--mono); }
.radio-node span { color: #a8ad9f; font: .72rem var(--mono); }
.air-path { position: absolute; left: 31%; right: 28%; top: 43%; height: 3px; background: var(--signal-bright); transform: rotate(13deg); transform-origin: left; z-index: 2; }
.air-path i { position: absolute; width: 55px; height: 55px; border: 1px solid var(--signal-bright); border-left: 0; border-bottom: 0; border-radius: 0 100% 0 0; top: -52px; }
.air-path i:nth-child(1) { left: 10%; transform: scale(.55); }
.air-path i:nth-child(2) { left: 19%; transform: scale(.8); }
.air-path i:nth-child(3) { left: 28%; }
.packet { position: absolute; top: -15px; left: 0; padding: 4px 8px; background: var(--signal); color: var(--ink); font: 800 .66rem var(--mono); animation: transmit 3.1s cubic-bezier(.2,.8,.2,1) infinite; }
@keyframes transmit { 0%,12% { left: 0; opacity: 0; } 18% { opacity: 1; } 70% { left: calc(100% - 48px); opacity: 1; } 80%,100% { left: calc(100% - 48px); opacity: 0; } }
.scope-trace { position: absolute; left: 0; right: 0; bottom: 4%; height: 120px; opacity: .55; }
.scope-trace svg { width: 100%; height: 100%; }
.scope-trace polyline { fill: none; stroke: var(--mint); stroke-width: 1.5; vector-effect: non-scaling-stroke; }

.baseline-strip { display: grid; grid-template-columns: repeat(4,1fr); border-bottom: 1px solid var(--line); }
.baseline-strip div { padding: 18px 22px; border-right: 1px solid var(--line); }
.baseline-strip span { display: block; color: var(--muted); font: 700 .62rem var(--mono); letter-spacing: .13em; }
.baseline-strip strong { display: block; margin-top: 4px; font: 800 .88rem var(--mono); }
.baseline-strip .warn { color: #b23c21; }

.lesson-panel { padding: clamp(42px,6vw,86px); border-bottom: 1px solid var(--line); background: var(--paper-deep); }
.lesson-header { display: grid; grid-template-columns: 100px 1fr auto; align-items: end; gap: 24px; }
.lesson-big-index { font: 900 6rem/.75 var(--display); color: var(--signal); }
.lesson-stage { margin: 0 0 5px; font: 700 .68rem var(--mono); letter-spacing: .14em; }
.lesson-title { margin: 0; font: 900 clamp(2.4rem,5vw,5.2rem)/.94 var(--display); }
.lesson-objective { max-width: 760px; margin: 30px 0; font-size: 1.08rem; }
.lesson-columns { display: grid; grid-template-columns: repeat(3,1fr); gap: 1px; background: var(--line); border: 1px solid var(--line); }
.lesson-card { min-height: 220px; padding: 24px; background: var(--paper); }
.lesson-card span { font: 700 .65rem var(--mono); color: var(--signal); letter-spacing: .14em; }
.lesson-card h3 { margin: 10px 0; font: 800 1.45rem var(--display); }
.lesson-card p, .lesson-card li { font-size: .9rem; }
.lesson-card ol { padding-left: 20px; }
.lesson-footer { display: flex; justify-content: space-between; gap: 20px; align-items: center; margin-top: 24px; }
.complete-button.done { background: var(--mint); box-shadow: none; }

.section-block { padding: clamp(50px,7vw,100px); border-bottom: 1px solid var(--line); }
.section-heading { display: flex; justify-content: space-between; align-items: start; margin-bottom: 24px; }
.section-heading h2 { margin: 8px 0 0; font: 900 clamp(2.5rem,5vw,5rem)/.9 var(--display); }
.section-number { font: 900 4rem var(--display); color: transparent; -webkit-text-stroke: 1px var(--ink); }
.section-intro { max-width: 720px; }
.packet-lab { background: var(--paper); }
.sim-grid { display: grid; grid-template-columns: minmax(280px,.7fr) minmax(420px,1.3fr); gap: clamp(30px,5vw,80px); margin-top: 40px; }
.control-board { border-top: 1px solid var(--ink); }
.toggle-row { display: grid; grid-template-columns: 1fr auto; position: relative; align-items: center; padding: 18px 2px; border-bottom: 1px solid var(--line); cursor: pointer; }
.toggle-row span { display: flex; flex-direction: column; }
.toggle-row strong { font-size: .9rem; }
.toggle-row small { color: var(--muted); }
.toggle-row input { position: absolute; opacity: 0; }
.toggle-row i { width: 46px; height: 24px; border: 1px solid var(--ink); border-radius: 30px; background: transparent; transition: background .2s; }
.toggle-row i::after { content: ""; display: block; width: 16px; height: 16px; margin: 3px; border-radius: 50%; background: var(--ink); transition: transform .2s; }
.toggle-row input:checked + i { background: var(--mint); }
.toggle-row input:checked + i::after { transform: translateX(22px); }
.toggle-row input:focus-visible + i { outline: 3px solid var(--blue); outline-offset: 3px; }
.sim-output { padding: 30px; color: var(--paper); background: var(--ink); }
.gate-track { position: relative; display: grid; grid-template-columns: repeat(4,1fr); gap: 12px; padding: 28px 10px 70px; border-bottom: 1px solid rgba(233,228,214,.2); }
.gate { height: 90px; display: grid; place-items: center; border: 1px solid rgba(233,228,214,.45); font: 700 .68rem var(--mono); transition: border .25s, background .25s; }
.gate.open { border-color: var(--mint); color: var(--mint); }
.gate.closed { border-color: var(--signal); color: var(--signal); background: rgba(255,92,53,.12); }
.sim-pulse { position: absolute; width: 12px; height: 12px; bottom: 27px; left: 5%; border-radius: 50%; background: var(--signal-bright); box-shadow: 0 0 16px var(--signal-bright); opacity: 0; }
.sim-pulse.run { animation: pulse-run 1.2s linear; }
@keyframes pulse-run { 0% { left: 5%; opacity: 1; } 90% { left: 93%; opacity: 1; } 100% { left: 93%; opacity: 0; } }
.result-card { padding: 26px 4px 4px; }
.result-code { font: 700 .68rem var(--mono); letter-spacing: .12em; color: var(--signal-bright); }
.result-card h3 { margin: 8px 0; font: 800 2rem var(--display); }
.result-card p { margin-bottom: 0; color: #bcc2b7; }
.result-card.pass h3 { color: var(--mint); }
.result-card.fail h3 { color: var(--signal); }

.serial-lab { background: #c9d0c2; }
.safety-banner { display: flex; gap: 20px; align-items: center; padding: 14px 18px; border: 1px solid var(--ink); background: var(--signal-bright); }
.safety-banner strong { font: 800 1rem var(--display); white-space: nowrap; }
.safety-banner span { font-size: .85rem; }
.support-note { margin: 20px 0; font: .78rem var(--mono); }
.support-note.error { color: #8f250f; }
.terminal-grid { display: grid; grid-template-columns: 1fr 1fr; gap: 18px; }
.terminal-card { min-height: 360px; background: var(--terminal); color: #d7fbd0; border: 1px solid var(--ink); box-shadow: 8px 8px 0 rgba(17,19,15,.25); }
.terminal-card header, .terminal-card footer { display: flex; align-items: center; justify-content: space-between; padding: 12px 16px; border-bottom: 1px solid #354137; font: 700 .7rem var(--mono); }
.terminal-card header strong { color: var(--signal); }
.terminal-card.connected header strong { color: var(--mint); }
.terminal-card footer { justify-content: flex-start; gap: 8px; border: 0; border-top: 1px solid #354137; }
.terminal-log { height: 270px; padding: 16px; overflow: auto; white-space: pre-wrap; word-break: break-all; font: .76rem/1.65 var(--mono); }
.terminal-log .rx { color: var(--mint); }
.terminal-log .tx { color: var(--signal-bright); }
.terminal-log .meta { color: #7f9282; }
.terminal-button { padding: 7px 11px; color: var(--terminal); background: var(--mint); border: 0; font: 700 .7rem var(--mono); }
.terminal-button.ghost { color: #b9c0b5; background: transparent; border: 1px solid #536056; }
.terminal-button:disabled { opacity: .35; cursor: not-allowed; }
.send-bar { display: grid; grid-template-columns: auto 120px auto 1fr auto; gap: 10px; align-items: center; margin-top: 24px; }
.send-bar label { font: 700 .72rem var(--mono); }
.send-bar input, .send-bar select { width: 100%; padding: 11px; border: 1px solid var(--ink); background: var(--paper); font: .78rem var(--mono); }

.frame-lab { background: #ffd24a; }
.frame-form { display: grid; grid-template-columns: 1fr auto; gap: 12px; margin: 35px 0 24px; }
.frame-form label { grid-column: 1 / -1; font: 700 .7rem var(--mono); letter-spacing: .12em; }
.frame-form input { min-width: 0; padding: 14px; border: 1px solid var(--ink); background: var(--paper); font: .82rem var(--mono); text-transform: uppercase; }
.frame-readout { display: grid; grid-template-columns: 180px 180px 1fr; border: 1px solid var(--ink); background: var(--ink); color: var(--paper); }
.frame-readout div { padding: 19px; border-right: 1px solid #4c5148; }
.frame-readout span { display: block; color: var(--signal-bright); font: 700 .64rem var(--mono); letter-spacing: .12em; }
.frame-readout strong, .frame-readout code { display: block; margin-top: 8px; font: 700 .88rem/1.6 var(--mono); color: var(--mint); word-break: break-all; }
.frame-error { min-height: 1.6em; color: #8f250f; font: 700 .78rem var(--mono); }

.reliability-lab { background: #b9e6f5; }
.reliable-controls { display: grid; grid-template-columns: repeat(4,minmax(110px,1fr)) auto; gap: 12px; align-items: end; margin: 34px 0; }
.reliable-controls label { display: flex; flex-direction: column; gap: 7px; font: 700 .67rem var(--mono); letter-spacing: .06em; }
.reliable-controls input { width: 100%; padding: 11px; border: 1px solid var(--ink); background: rgba(255,255,255,.45); font: 800 1rem var(--mono); }
.protocol-grid { display: grid; grid-template-columns: .7fr 1.3fr; gap: 16px; }
.protocol-stats { display: grid; grid-template-columns: 1fr 1fr; gap: 1px; padding: 1px; background: var(--ink); }
.protocol-stats div { min-height: 126px; padding: 20px; background: var(--paper); }
.protocol-stats span { display: block; font: 700 .65rem var(--mono); color: var(--muted); }
.protocol-stats strong { display: block; margin-top: 15px; font: 900 2.8rem/.9 var(--display); }
.protocol-log { height: 253px; overflow: auto; padding: 18px; background: var(--terminal); color: #cdd7cc; font: .72rem/1.7 var(--mono); }
.protocol-log p { margin: 0 0 4px; }
.protocol-log .drop { color: var(--signal); }
.protocol-log .ack { color: var(--mint); }
.protocol-log .retry { color: var(--signal-bright); }

.telemetry-lab { background: var(--ink); color: var(--paper); }
.telemetry-lab .section-number { -webkit-text-stroke-color: var(--paper); }
.telemetry-toolbar { display: flex; align-items: center; gap: 12px; flex-wrap: wrap; margin: 30px 0; }
.telemetry-toolbar .secondary-button { color: var(--paper); border-color: var(--paper); }
.telemetry-toolbar code { margin-left: auto; padding: 10px 13px; color: var(--mint); background: #20251f; font: .7rem var(--mono); }
.telemetry-metrics { display: grid; grid-template-columns: 1.3fr 1.3fr repeat(3,1fr); border: 1px solid #454b43; }
.telemetry-metrics div { padding: 19px; border-right: 1px solid #454b43; }
.telemetry-metrics span { display: block; color: #959d91; font: 700 .62rem var(--mono); letter-spacing: .1em; }
.telemetry-metrics strong { display: inline-block; margin-top: 8px; font: 900 2.5rem var(--display); }
.telemetry-metrics small { margin-left: 6px; color: var(--signal-bright); font: .7rem var(--mono); }
.telemetry-chart { margin-top: 18px; padding: 22px; border: 1px solid #454b43; background: #090c09; }
.chart-key { display: flex; gap: 18px; font: 700 .65rem var(--mono); }
.chart-key span::before { content: ""; display: inline-block; width: 20px; height: 3px; margin-right: 7px; vertical-align: middle; background: currentColor; }
.temp-key { color: var(--signal); }.humidity-key { color: var(--blue); }
.telemetry-chart svg { width: 100%; height: 280px; margin-top: 12px; overflow: visible; }
.chart-grid path { fill: none; stroke: #30372f; stroke-width: 1; vector-effect: non-scaling-stroke; }
.temp-line, .humidity-line { fill: none; stroke-width: 3; vector-effect: non-scaling-stroke; }
.temp-line { stroke: var(--signal); }.humidity-line { stroke: var(--blue); }
.telemetry-chart p { margin: 5px 0 0; color: #91998e; font: .7rem var(--mono); }

.safety-lab { background: #ff6640; }
.safety-console { display: grid; grid-template-columns: minmax(300px,.8fr) 1.2fr; gap: 50px; align-items: center; margin-top: 35px; }
.state-orbit { width: min(380px,80vw); aspect-ratio: 1; position: relative; display: grid; place-items: center; margin: auto; }
.state-orbit > i { position: absolute; inset: 4%; border: 1px solid rgba(17,19,15,.45); border-radius: 50%; }
.state-orbit > i:nth-child(2) { inset: 14%; border-style: dashed; animation: orbit 16s linear infinite; }
.state-orbit > i:nth-child(3) { inset: 25%; border-width: 2px; }
@keyframes orbit { to { transform: rotate(360deg); } }
.state-core { position: relative; z-index: 2; width: 48%; aspect-ratio: 1; display: flex; flex-direction: column; align-items: center; justify-content: center; border-radius: 50%; color: var(--paper); background: var(--ink); box-shadow: 0 0 0 12px rgba(17,19,15,.12); transition: background .25s, transform .25s; }
.state-core small { font: 700 .6rem var(--mono); letter-spacing: .15em; }
.state-core strong { font: 900 2rem var(--display); }
.state-core span { font: 700 .75rem var(--mono); color: var(--signal-bright); }
.state-core.armed { background: #3e4a1e; }.state-core.active { background: #006f70; transform: scale(1.06); }.state-core.lost { background: #8a1708; }
.state-controls { display: grid; grid-template-columns: 1fr 1fr; gap: 12px; }
.command-button { grid-column: 1 / -1; padding: 18px; border: 2px solid var(--ink); background: var(--mint); font: 900 1rem var(--mono); box-shadow: 6px 6px 0 var(--ink); }
.command-button:disabled { opacity: .36; box-shadow: none; cursor: not-allowed; }
.safety-log { grid-column: 1 / -1; min-height: 130px; max-height: 210px; overflow: auto; padding: 16px; background: var(--ink); color: var(--paper); white-space: pre-line; font: .72rem/1.7 var(--mono); }

.notebook { background: var(--paper-deep); }
.notebook-grid { display: grid; grid-template-columns: repeat(3,1fr); gap: 14px; }
.notebook-grid label { display: flex; flex-direction: column; gap: 8px; }
.notebook-grid span { font: 700 .7rem var(--mono); letter-spacing: .1em; }
.notebook-grid textarea { min-height: 190px; resize: vertical; border: 1px solid var(--ink); background: rgba(255,255,255,.35); padding: 16px; }
.notebook-grid label:nth-child(1) span { color: #1a5f79; }
.notebook-grid label:nth-child(2) span { color: #9b3119; }
.notebook-grid label:nth-child(3) span { color: #5a6830; }
.notebook-actions { display: flex; align-items: center; justify-content: flex-end; gap: 12px; margin-top: 16px; }
.notebook-actions span { margin-right: auto; color: var(--muted); font: .72rem var(--mono); }
.site-footer { display: flex; justify-content: space-between; padding: 28px 3vw; background: var(--ink); color: var(--paper); font: .7rem var(--mono); }
.site-footer p { margin: 0; color: #9ca397; }

@media (max-width: 1050px) {
  .app-shell { grid-template-columns: 1fr; }
  .course-rail { min-height: 0; position: static; max-height: none; border-right: 0; border-bottom: 1px solid var(--line); }
  #lesson-nav { display: grid; grid-template-columns: repeat(5,1fr); }
  .lesson-nav-button { grid-template-columns: 28px 1fr; }
  .lesson-nav-button .nav-check { display: none; }
  .rail-note { display: none; }
  .hero-panel { grid-template-columns: 1fr; }
  .radio-stage { min-height: 470px; }
  .baseline-strip { grid-template-columns: repeat(2,1fr); }
  .lesson-columns, .notebook-grid { grid-template-columns: 1fr; }
}

@media (max-width: 720px) {
  .masthead { height: 76px; padding: 0 16px; }
  .brand-mark { width: 42px; height: 42px; }
  .brand-lockup h1 { font-size: 1.1rem; }
  .brand-lockup .eyebrow, .mast-status span:not(.status-dot) { display: none; }
  .course-rail { padding: 18px 14px; }
  #lesson-nav { grid-template-columns: repeat(2,1fr); }
  .hero-copy { padding: 56px 24px; }
  .hero-copy h2 { font-size: 4rem; }
  .radio-node { width: 155px; padding: 14px; }
  .node-a { left: 5%; }.node-b { right: 5%; }
  .baseline-strip { grid-template-columns: 1fr 1fr; }
  .lesson-panel, .section-block { padding: 48px 22px; }
  .lesson-header { grid-template-columns: 64px 1fr; }
  .lesson-big-index { font-size: 4rem; }
  .lesson-header .complete-button { grid-column: 1 / -1; }
  .sim-grid, .terminal-grid { grid-template-columns: 1fr; }
  .sim-grid { gap: 24px; }
  .gate-track { gap: 5px; }
  .send-bar { grid-template-columns: auto 1fr; }
  .send-bar input, .send-bar .primary-button { grid-column: 1 / -1; }
  .frame-form, .frame-readout { grid-template-columns: 1fr; }
  .frame-form .primary-button { width: 100%; }
  .frame-readout div { border-right: 0; border-bottom: 1px solid #4c5148; }
  .reliable-controls { grid-template-columns: 1fr 1fr; }
  .reliable-controls .primary-button { grid-column: 1 / -1; }
  .protocol-grid, .safety-console { grid-template-columns: 1fr; }
  .telemetry-metrics { grid-template-columns: 1fr 1fr; }
  .telemetry-metrics div { border-bottom: 1px solid #454b43; }
  .telemetry-toolbar code { width: 100%; overflow-x: auto; }
  .safety-banner { align-items: start; flex-direction: column; gap: 3px; }
  .notebook-actions { flex-wrap: wrap; }
  .notebook-actions span { width: 100%; }
  .site-footer { flex-direction: column; gap: 8px; }
}

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