:root {
  --bg: #06101d;
  --bg-soft: #0a1727;
  --panel: rgba(10, 24, 40, 0.78);
  --panel-strong: #0d1d30;
  --border: rgba(147, 181, 211, 0.16);
  --border-strong: rgba(93, 204, 255, 0.34);
  --text: #edf6ff;
  --muted: #9eb0c3;
  --faint: #6e8298;
  --cyan: #67d5ff;
  --cyan-strong: #23bdf8;
  --green: #71e4b6;
  --amber: #ffd479;
  --radius: 18px;
  --shadow: 0 22px 70px rgba(0,0,0,.28);
  --max: 1180px;
}

* { box-sizing: border-box; }
html { scroll-behavior: smooth; }
body {
  margin: 0;
  min-width: 320px;
  background:
    radial-gradient(circle at 12% 8%, rgba(25, 135, 205, .12), transparent 27rem),
    radial-gradient(circle at 90% 18%, rgba(55, 211, 162, .08), transparent 24rem),
    var(--bg);
  color: var(--text);
  font-family: Inter, ui-sans-serif, system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
  line-height: 1.6;
  overflow-x: hidden;
}

a { color: inherit; }
button, a { -webkit-tap-highlight-color: transparent; }
button { font: inherit; }

.ambient {
  position: fixed;
  border-radius: 999px;
  filter: blur(100px);
  opacity: .12;
  pointer-events: none;
  z-index: -1;
}
.ambient-one { width: 24rem; height: 24rem; background: #0fb8ff; top: 10rem; left: -10rem; }
.ambient-two { width: 30rem; height: 30rem; background: #35d8a0; right: -16rem; top: 28rem; }

.shell { width: min(var(--max), calc(100% - 40px)); margin-inline: auto; }

.site-header {
  position: sticky;
  top: 0;
  z-index: 50;
  border-bottom: 1px solid var(--border);
  background: rgba(6, 16, 29, .84);
  backdrop-filter: blur(18px);
}

.nav {
  min-height: 72px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 28px;
}

.brand {
  display: inline-flex;
  align-items: center;
  gap: 11px;
  text-decoration: none;
}
.brand-mark {
  width: 38px;
  height: 38px;
  border: 1px solid var(--border-strong);
  border-radius: 11px;
  display: grid;
  place-items: center;
  color: var(--cyan);
  font: 800 13px/1 ui-monospace, SFMono-Regular, Menlo, Consolas, monospace;
  letter-spacing: .08em;
  box-shadow: inset 0 0 22px rgba(35,189,248,.06);
}
.brand strong, .brand small { display: block; }
.brand strong { font-size: 14px; letter-spacing: .02em; }
.brand small { color: var(--muted); font-size: 11px; margin-top: 1px; }

.nav-links { display: flex; align-items: center; gap: 22px; }
.nav-links a {
  color: var(--muted);
  text-decoration: none;
  font-size: 13px;
  font-weight: 650;
}
.nav-links a:hover { color: var(--text); }
.nav-links .linkedin-link { color: var(--cyan); }

.nav-toggle {
  display: none;
  color: var(--text);
  border: 1px solid var(--border);
  background: var(--panel);
  border-radius: 10px;
  padding: 8px 11px;
}

.hero {
  padding: 104px 0 62px;
  display: grid;
  grid-template-columns: minmax(0, 1.12fr) minmax(340px, .88fr);
  align-items: center;
  gap: 68px;
}

.eyebrow {
  margin: 0 0 10px;
  color: var(--cyan);
  font: 760 12px/1.4 ui-monospace, SFMono-Regular, Menlo, Consolas, monospace;
  letter-spacing: .16em;
}
.owner { margin: 0 0 24px; color: var(--muted); font-size: 13px; }
.owner a { color: var(--text); text-decoration-color: rgba(103,213,255,.5); text-underline-offset: 3px; }

.hero h1 {
  margin: 0;
  max-width: 820px;
  font-size: clamp(48px, 6.4vw, 84px);
  line-height: .99;
  letter-spacing: -.055em;
}
.hero h1 span {
  color: transparent;
  background: linear-gradient(90deg, #eef8ff 3%, #70d9ff 48%, #71e4b6 96%);
  background-clip: text;
  -webkit-background-clip: text;
}
.hero-text {
  max-width: 760px;
  margin: 28px 0 0;
  color: var(--muted);
  font-size: 17px;
}
.hero-text strong { color: #d9efff; font-weight: 680; }

.hero-actions { display: flex; gap: 12px; flex-wrap: wrap; margin-top: 34px; }

.button {
  min-height: 46px;
  padding: 0 18px;
  border-radius: 11px;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  border: 1px solid var(--border);
  text-decoration: none;
  font-weight: 760;
  font-size: 13px;
  cursor: pointer;
}
.button.primary {
  background: linear-gradient(135deg, #1ebff9, #66d6ff);
  color: #03101b;
  border-color: transparent;
  box-shadow: 0 10px 30px rgba(35, 189, 248, .17);
}
.button.secondary {
  background: rgba(9, 24, 40, .72);
  color: var(--text);
}
.button.small { min-height: 38px; padding-inline: 14px; margin-top: 18px; }

.platform-strip { display: flex; flex-wrap: wrap; gap: 8px; margin-top: 30px; }
.platform-strip span {
  border: 1px solid var(--border);
  background: rgba(9, 22, 37, .58);
  color: #a9bfd3;
  border-radius: 999px;
  padding: 7px 10px;
  font: 650 11px/1 ui-monospace, SFMono-Regular, Menlo, Consolas, monospace;
}

.terminal-card {
  border: 1px solid var(--border);
  background: linear-gradient(180deg, rgba(12, 29, 48, .88), rgba(7, 19, 32, .94));
  border-radius: var(--radius);
  box-shadow: var(--shadow);
  overflow: hidden;
  transform: translateY(8px);
}
.terminal-top {
  height: 46px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 0 15px;
  border-bottom: 1px solid var(--border);
  color: var(--faint);
  font: 600 11px/1 ui-monospace, SFMono-Regular, Menlo, Consolas, monospace;
}
.terminal-dots { display: flex; gap: 6px; }
.terminal-dots i { width: 8px; height: 8px; border-radius: 50%; background: #4d6479; display: block; }
.terminal-dots i:nth-child(2) { background: #66798a; }
.terminal-dots i:nth-child(3) { background: #8295a6; }

.terminal-card pre {
  margin: 0;
  padding: 26px;
  min-height: 348px;
  overflow: auto;
  color: #d8e9f6;
  font: 500 12.5px/1.72 ui-monospace, SFMono-Regular, Menlo, Consolas, monospace;
}
.terminal-card .muted { color: #8fa4b7; }
.terminal-card .value { color: var(--green); }
.terminal-card .comment { color: #71869a; }
.terminal-foot {
  border-top: 1px solid var(--border);
  display: flex;
  justify-content: space-between;
  gap: 20px;
  padding: 13px 16px;
  color: var(--faint);
  font: 700 10px/1 ui-monospace, SFMono-Regular, Menlo, Consolas, monospace;
  letter-spacing: .12em;
}

.stats {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  border: 1px solid var(--border);
  background: rgba(9, 23, 38, .54);
  border-radius: var(--radius);
  overflow: hidden;
}
.stats article { padding: 22px; border-right: 1px solid var(--border); }
.stats article:last-child { border-right: 0; }
.stats strong { display: block; color: var(--cyan); font: 780 26px/1 ui-monospace, SFMono-Regular, Menlo, Consolas, monospace; }
.stats span { display: block; color: var(--muted); font-size: 12px; margin-top: 8px; }

.section { padding: 96px 0 14px; }
.section-heading { max-width: 780px; margin-bottom: 35px; }
.section-heading h2 {
  margin: 0;
  font-size: clamp(32px, 4vw, 52px);
  line-height: 1.07;
  letter-spacing: -.04em;
}
.section-heading > p:last-child { color: var(--muted); margin: 16px 0 0; font-size: 15px; }

.command-layout {
  display: grid;
  grid-template-columns: 220px 1fr;
  gap: 16px;
}
.track-tabs {
  border: 1px solid var(--border);
  background: rgba(8, 21, 35, .64);
  border-radius: var(--radius);
  padding: 9px;
  height: max-content;
}
.track-tab {
  width: 100%;
  border: 0;
  background: transparent;
  color: var(--muted);
  padding: 13px 12px;
  border-radius: 10px;
  text-align: left;
  cursor: pointer;
  font-weight: 700;
}
.track-tab:hover { color: var(--text); background: rgba(255,255,255,.025); }
.track-tab.active { color: #06131f; background: linear-gradient(135deg, #6ad7ff, #73e3b7); }

.command-panel {
  border: 1px solid var(--border);
  background: linear-gradient(155deg, rgba(12, 30, 49, .9), rgba(8, 20, 34, .88));
  border-radius: var(--radius);
  padding: 24px;
}
.command-kicker, .progress-row {
  display: flex;
  justify-content: space-between;
  gap: 18px;
  align-items: center;
}
.command-kicker {
  color: var(--faint);
  font: 700 10px/1.3 ui-monospace, SFMono-Regular, Menlo, Consolas, monospace;
  letter-spacing: .12em;
}
.command-grid {
  display: grid;
  grid-template-columns: 1.15fr .85fr;
  gap: 24px;
  margin-top: 36px;
}
.command-grid h3 { font-size: 31px; margin: 7px 0 10px; letter-spacing: -.03em; }
.command-grid p { color: var(--muted); margin: 0; }
.mini-label { color: var(--cyan) !important; font: 700 10px/1.4 ui-monospace, SFMono-Regular, Menlo, Consolas, monospace; letter-spacing: .13em; }
.next-action {
  padding: 18px;
  border: 1px solid rgba(113,228,182,.18);
  background: rgba(35, 113, 91, .07);
  border-radius: 13px;
}
.next-action span { display: block; color: var(--green); font: 700 10px/1 ui-monospace, SFMono-Regular, Menlo, Consolas, monospace; letter-spacing: .12em; margin-bottom: 10px; }
.next-action strong { display: block; font-size: 13px; line-height: 1.65; color: #d9eee6; }
.progress-row { margin-top: 28px; color: var(--muted); font-size: 11px; }
.progress-row strong { color: var(--text); }
.progress { height: 5px; background: rgba(255,255,255,.06); border-radius: 999px; margin-top: 9px; overflow: hidden; }
.progress i { display: block; height: 100%; width: 0; background: linear-gradient(90deg, var(--cyan-strong), var(--green)); transition: width .25s ease; }

.cards { display: grid; grid-template-columns: repeat(3, 1fr); gap: 15px; }
.card {
  min-height: 360px;
  display: flex;
  flex-direction: column;
  border: 1px solid var(--border);
  background: linear-gradient(165deg, rgba(11, 27, 45, .74), rgba(7, 19, 32, .65));
  border-radius: var(--radius);
  padding: 24px;
  box-shadow: 0 18px 46px rgba(0,0,0,.08);
}
.card.featured { border-color: rgba(103,213,255,.36); box-shadow: inset 0 0 50px rgba(35,189,248,.035); }
.card.cloud-card { border-color: rgba(113,228,182,.22); }
.card-number { color: var(--cyan); font: 740 10px/1 ui-monospace, SFMono-Regular, Menlo, Consolas, monospace; letter-spacing: .12em; }
.card h3 { margin: 15px 0 8px; font-size: 22px; letter-spacing: -.025em; }
.card p { color: var(--muted); font-size: 14px; margin: 0; }
.card ul { color: #b4c7d7; font-size: 12px; padding-left: 18px; margin: 20px 0 24px; }
.card li { margin-bottom: 7px; }
.card a, .text-button {
  margin-top: auto;
  color: var(--cyan);
  text-decoration: none;
  font-size: 12px;
  font-weight: 760;
}
.text-button { padding: 0; border: 0; background: transparent; width: max-content; cursor: pointer; }

.cloud-section {
  margin-top: 96px;
  padding: 92px 0;
  border-block: 1px solid var(--border);
  background:
    linear-gradient(180deg, rgba(15, 39, 61, .52), rgba(5, 16, 28, .75)),
    radial-gradient(circle at 65% 20%, rgba(31,187,249,.10), transparent 27rem);
}
.cloud-grid { display: grid; grid-template-columns: repeat(4, 1fr); gap: 14px; }
.cloud-grid article {
  min-height: 250px;
  padding: 22px;
  border: 1px solid var(--border);
  border-radius: 16px;
  background: rgba(6, 18, 31, .62);
}
.cloud-icon {
  width: 42px;
  height: 42px;
  display: grid;
  place-items: center;
  border-radius: 10px;
  background: rgba(103,213,255,.08);
  border: 1px solid rgba(103,213,255,.18);
  color: var(--cyan);
  font: 800 10px/1 ui-monospace, SFMono-Regular, Menlo, Consolas, monospace;
}
.cloud-grid h3 { font-size: 18px; margin: 19px 0 10px; }
.cloud-grid p { color: var(--muted); font-size: 13px; margin: 0; }

.cloud-flow {
  margin-top: 30px;
  padding: 18px;
  border: 1px solid var(--border);
  border-radius: 16px;
  display: grid;
  grid-template-columns: 1fr auto 1fr auto 1fr auto 1fr auto 1fr;
  align-items: center;
  gap: 10px;
  background: rgba(4, 15, 26, .56);
}
.cloud-flow > div { padding: 8px; }
.cloud-flow span { display: block; color: var(--cyan); font: 720 10px/1 ui-monospace, SFMono-Regular, Menlo, Consolas, monospace; }
.cloud-flow strong { display: block; margin-top: 7px; font-size: 14px; }
.cloud-flow small { display: block; color: var(--faint); font-size: 10px; margin-top: 3px; }
.cloud-flow i { color: var(--faint); font-style: normal; }

.roadmap { list-style: none; margin: 0; padding: 0; border-top: 1px solid var(--border); }
.roadmap li {
  display: grid;
  grid-template-columns: 90px 1fr;
  gap: 18px;
  padding: 23px 0;
  border-bottom: 1px solid var(--border);
}
.roadmap > li > span { color: var(--cyan); font: 750 12px/1.4 ui-monospace, SFMono-Regular, Menlo, Consolas, monospace; }
.roadmap h3 { margin: 0; font-size: 18px; }
.roadmap p { color: var(--muted); margin: 6px 0 0; font-size: 13px; }

.reference-flow {
  display: grid;
  grid-template-columns: 1fr auto 1.15fr auto 1.15fr;
  gap: 14px;
  align-items: center;
}
.flow-stack { display: grid; gap: 10px; }
.flow-node {
  border: 1px solid var(--border);
  background: rgba(9, 23, 38, .7);
  border-radius: 13px;
  padding: 17px;
}
.flow-node.control { border-color: rgba(103,213,255,.34); }
.flow-node.cloud { border-color: rgba(113,228,182,.22); }
.flow-node small { display: block; color: var(--cyan); font: 700 9px/1 ui-monospace, SFMono-Regular, Menlo, Consolas, monospace; letter-spacing: .11em; margin-bottom: 7px; }
.flow-node strong { display: block; font-size: 14px; }
.flow-node span { display: block; color: var(--faint); font-size: 10px; margin-top: 4px; }
.arrow { color: var(--faint); }

.linkedin-section {
  margin-top: 96px;
  padding: 58px 0;
  border-block: 1px solid var(--border);
  background: linear-gradient(120deg, rgba(11, 40, 60, .7), rgba(10, 31, 39, .48));
}
.linkedin-wrap { display: flex; justify-content: space-between; align-items: center; gap: 36px; }
.linkedin-wrap > div { max-width: 730px; }
.linkedin-wrap h2 { font-size: 36px; margin: 0; letter-spacing: -.035em; }
.linkedin-wrap p:last-child { color: var(--muted); margin-bottom: 0; }

.safety-grid { display: grid; grid-template-columns: repeat(4, 1fr); gap: 13px; }
.safety-grid article { padding: 19px; border: 1px solid var(--border); background: rgba(8, 21, 35, .56); border-radius: 14px; }
.safety-grid strong { color: #dcebf6; font-size: 13px; }
.safety-grid p { color: var(--muted); font-size: 11.5px; margin: 8px 0 0; }

.footer { margin-top: 100px; padding: 30px 0; border-top: 1px solid var(--border); background: rgba(4, 13, 23, .7); }
.footer-inner { display: flex; align-items: center; justify-content: space-between; gap: 20px; }
.footer-links { display: flex; gap: 20px; }
.footer-links a { color: var(--muted); text-decoration: none; font-size: 12px; }

@media (max-width: 1020px) {
  .hero { grid-template-columns: 1fr; gap: 40px; padding-top: 76px; }
  .terminal-card { max-width: 720px; }
  .cards { grid-template-columns: repeat(2, 1fr); }
  .cloud-grid { grid-template-columns: repeat(2, 1fr); }
  .safety-grid { grid-template-columns: repeat(2, 1fr); }
  .reference-flow { grid-template-columns: 1fr; }
  .reference-flow .arrow { transform: rotate(90deg); text-align: center; }
}

@media (max-width: 760px) {
  .shell { width: min(100% - 28px, var(--max)); }
  .nav-toggle { display: block; }
  .nav-links {
    position: absolute;
    top: 71px;
    left: 14px;
    right: 14px;
    display: none;
    flex-direction: column;
    align-items: stretch;
    gap: 0;
    padding: 10px;
    border: 1px solid var(--border);
    border-radius: 14px;
    background: #0a1828;
    box-shadow: var(--shadow);
  }
  .nav-links.open { display: flex; }
  .nav-links a { padding: 12px; }
  .hero { padding-top: 58px; }
  .hero h1 { font-size: clamp(43px, 14vw, 68px); }
  .stats { grid-template-columns: repeat(2, 1fr); }
  .stats article:nth-child(2) { border-right: 0; }
  .stats article:nth-child(-n+2) { border-bottom: 1px solid var(--border); }
  .command-layout { grid-template-columns: 1fr; }
  .track-tabs { display: grid; grid-template-columns: repeat(2, 1fr); }
  .command-grid { grid-template-columns: 1fr; }
  .cards, .cloud-grid, .safety-grid { grid-template-columns: 1fr; }
  .cloud-flow { grid-template-columns: 1fr; }
  .cloud-flow i { transform: rotate(90deg); text-align: center; }
  .linkedin-wrap { align-items: flex-start; flex-direction: column; }
  .footer-inner { align-items: flex-start; flex-direction: column; }
}

@media (max-width: 480px) {
  .hero-actions { flex-direction: column; }
  .button { width: 100%; }
  .stats { grid-template-columns: 1fr; }
  .stats article { border-right: 0; border-bottom: 1px solid var(--border); }
  .stats article:last-child { border-bottom: 0; }
  .track-tabs { grid-template-columns: 1fr; }
  .terminal-card pre { padding: 18px; font-size: 11px; }
  .roadmap li { grid-template-columns: 48px 1fr; }
}


/* Linux / UNIX Engineering Lab */
.linux-terminal .terminal-screen {
  min-height: 184px;
  padding: 26px 26px 14px;
  background: rgba(2, 11, 20, .54);
  font: 500 13px/1.75 ui-monospace, SFMono-Regular, Menlo, Consolas, monospace;
}
.terminal-line { min-width: 0; overflow-wrap: anywhere; }
.terminal-muted { color: #64798c; }
.prompt { color: var(--green); font-weight: 700; }
.terminal-output { color: #d7e8f4; white-space: pre-wrap; margin-top: 5px; }
.terminal-concept {
  padding: 16px 26px 18px;
  border-top: 1px solid var(--border);
  background: rgba(9, 24, 39, .45);
}
.terminal-concept span {
  color: var(--cyan);
  font: 720 9px/1 ui-monospace, SFMono-Regular, Menlo, Consolas, monospace;
  letter-spacing: .13em;
}
.terminal-concept strong { display: block; margin-top: 7px; font-size: 14px; }
.terminal-concept p { color: var(--muted); font-size: 11.5px; margin: 5px 0 0; }
.terminal-actions {
  display: grid;
  grid-template-columns: 1fr 1fr 1fr;
  border-top: 1px solid var(--border);
}
.terminal-control {
  min-height: 40px;
  border: 0;
  border-right: 1px solid var(--border);
  color: #a9bfd1;
  background: rgba(8, 19, 32, .78);
  cursor: pointer;
  font: 700 10px/1 ui-monospace, SFMono-Regular, Menlo, Consolas, monospace;
}
.terminal-control:last-child { border-right: 0; }
.terminal-control:hover, .terminal-control:focus-visible { color: var(--text); background: rgba(20, 42, 64, .78); }

.linux-lab-section { scroll-margin-top: 90px; }
.linux-lab-grid {
  display: grid;
  grid-template-columns: minmax(0, 1.55fr) minmax(280px, .75fr);
  gap: 16px;
}
.linux-console-card, .linux-radar, .concept-card {
  border: 1px solid var(--border);
  border-radius: var(--radius);
  background: linear-gradient(165deg, rgba(11, 27, 45, .76), rgba(7, 19, 32, .7));
}
.linux-console-card { overflow: hidden; }
.linux-console-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 18px;
  padding: 14px 17px;
  border-bottom: 1px solid var(--border);
  color: var(--faint);
  font: 700 10px/1.2 ui-monospace, SFMono-Regular, Menlo, Consolas, monospace;
  letter-spacing: .10em;
}
.linux-console-header > div { display: flex; gap: 8px; align-items: center; }
.status-dot { width: 7px; height: 7px; border-radius: 50%; background: var(--green); box-shadow: 0 0 0 4px rgba(113, 228, 182, .06); }
.linux-console {
  min-height: 210px;
  padding: 28px;
  background: #04101c;
  color: #d8e8f4;
  font: 500 13px/1.75 ui-monospace, SFMono-Regular, Menlo, Consolas, monospace;
  outline: none;
}
.linux-console:focus-visible { box-shadow: inset 0 0 0 2px rgba(103, 213, 255, .38); }
.linux-explainer { padding: 22px 24px 24px; }
.linux-explainer h3 { margin: 7px 0 8px; font-size: 22px; }
.linux-explainer p { color: var(--muted); margin: 0; font-size: 13px; }
.linux-explainer code, .concept-card code, .command-group code {
  font-family: ui-monospace, SFMono-Regular, Menlo, Consolas, monospace;
}
.operator-note {
  display: grid;
  grid-template-columns: auto 1fr;
  gap: 8px;
  margin-top: 16px;
  padding: 13px 14px;
  border: 1px solid rgba(113, 228, 182, .15);
  background: rgba(47, 125, 98, .05);
  border-radius: 11px;
  font-size: 11.5px;
}
.operator-note strong { color: var(--green); }
.operator-note span { color: #b6c9d5; }

.linux-radar { padding: 23px; }
.linux-radar .eyebrow { margin-bottom: 18px; }
.radar-row {
  display: flex;
  justify-content: space-between;
  gap: 18px;
  padding: 11px 0;
  border-bottom: 1px solid var(--border);
  font-size: 11.5px;
}
.radar-row span { color: var(--muted); }
.radar-row strong { text-align: right; color: #dcebf5; }
.radar-next {
  margin-top: 17px;
  padding: 15px;
  border: 1px solid rgba(255, 212, 121, .17);
  background: rgba(129, 96, 32, .055);
  border-radius: 12px;
}
.radar-next span { color: var(--amber); font: 720 9px/1 ui-monospace, SFMono-Regular, Menlo, Consolas, monospace; letter-spacing: .13em; }
.radar-next strong { display: block; margin-top: 8px; font-size: 12px; }
.radar-next p { color: var(--muted); font-size: 10.5px; margin: 6px 0 0; }
.radar-verified { color: var(--faint); font-size: 9.5px; margin: 15px 0 7px; }
.text-link { color: var(--cyan); font-size: 11px; text-decoration: none; font-weight: 700; }

.lesson-tabs {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  margin: 20px 0 0;
}
.lesson-tab {
  min-height: 36px;
  border: 1px solid var(--border);
  background: rgba(8, 21, 35, .56);
  color: var(--muted);
  border-radius: 999px;
  padding: 0 12px;
  cursor: pointer;
  font: 700 10px/1 ui-monospace, SFMono-Regular, Menlo, Consolas, monospace;
}
.lesson-tab.active {
  color: #06131f;
  border-color: transparent;
  background: linear-gradient(135deg, #6ad7ff, #73e3b7);
}
.lesson-tab:hover { color: var(--text); }

.linux-deep-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 14px;
  margin-top: 24px;
}
.concept-card { padding: 22px; }
.concept-card h3 { margin: 8px 0 10px; font-size: 18px; }
.concept-card p { color: var(--muted); font-size: 12px; margin: 0; }
.concept-card pre {
  overflow: auto;
  padding: 14px;
  border: 1px solid var(--border);
  border-radius: 10px;
  background: #04101c;
  color: #d5e7f3;
  font: 500 11px/1.6 ui-monospace, SFMono-Regular, Menlo, Consolas, monospace;
}
.pipeline-visual {
  display: flex;
  align-items: center;
  flex-wrap: wrap;
  gap: 7px;
  margin: 16px 0;
}
.pipeline-visual span {
  border: 1px solid var(--border);
  background: #061422;
  border-radius: 8px;
  padding: 8px 9px;
  color: #d6e8f5;
  font: 650 10px/1 ui-monospace, SFMono-Regular, Menlo, Consolas, monospace;
}
.pipeline-visual i { color: var(--cyan); font-style: normal; font-size: 10px; }
.concept-list { margin: 14px 0 0; padding-left: 18px; color: var(--muted); font-size: 11.5px; }
.concept-list li { margin-bottom: 6px; }

.command-matrix {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 12px;
  margin-top: 24px;
}
.command-group {
  padding: 18px;
  border: 1px solid var(--border);
  border-radius: 14px;
  background: rgba(8, 21, 35, .54);
}
.command-group h3 { font-size: 13px; margin: 0 0 12px; }
.command-group code {
  display: inline-block;
  margin: 3px 4px 3px 0;
  padding: 6px 7px;
  border-radius: 7px;
  border: 1px solid var(--border);
  color: #b8cedd;
  background: #06131f;
  font-size: 9.5px;
}

@media (max-width: 1020px) {
  .linux-lab-grid { grid-template-columns: 1fr; }
  .linux-deep-grid { grid-template-columns: 1fr; }
  .command-matrix { grid-template-columns: repeat(2, 1fr); }
}
@media (max-width: 620px) {
  .command-matrix { grid-template-columns: 1fr; }
  .linux-console { padding: 20px; font-size: 11.5px; }
  .operator-note { grid-template-columns: 1fr; }
  .terminal-actions { grid-template-columns: 1fr; }
  .terminal-control { border-right: 0; border-bottom: 1px solid var(--border); }
  .terminal-control:last-child { border-bottom: 0; }
}