/* ============================================================
   Linux krúžok - 33 hodín
   Tmavý režim, terminálová estetika, timeline navigácia
   ============================================================ */

:root {
  --bg: #0d1117;
  --bg-elevated: #161b22;
  --bg-hover: #1c2128;
  --border: #30363d;
  --border-light: #484f58;
  --text: #e6edf3;
  --text-muted: #8b949e;
  --accent: #58a6ff;
  --accent-green: #3fb950;
  --accent-yellow: #d29922;
  --accent-red: #f85149;
  --accent-purple: #bc8cff;
  --terminal-bg: #010409;
  --mono: "JetBrains Mono", "Fira Code", "Cascadia Code", Menlo, Consolas, monospace;
  --sans: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
  --radius: 8px;
  --sidebar-w: 300px;
}

* {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

html {
  scroll-behavior: smooth;
  scroll-padding-top: 70px;
}

body {
  background: var(--bg);
  color: var(--text);
  font-family: var(--sans);
  line-height: 1.65;
  font-size: 16px;
}

/* ============ LAYOUT ============ */
.layout {
  display: grid;
  grid-template-columns: var(--sidebar-w) 1fr;
  min-height: 100vh;
}

/* ============ TOP BAR ============ */
.topbar {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  height: 58px;
  background: var(--bg-elevated);
  border-bottom: 1px solid var(--border);
  display: flex;
  align-items: center;
  gap: 16px;
  padding: 0 20px;
  z-index: 100;
}

.topbar .brand {
  font-weight: 700;
  font-size: 18px;
  letter-spacing: 0.3px;
  white-space: nowrap;
}

.topbar .brand .prompt {
  color: var(--accent-green);
  margin-right: 6px;
  font-family: var(--mono);
}

.topbar .brand .slash {
  color: var(--accent);
}

.topbar .hamburger {
  display: none;
  background: none;
  border: 1px solid var(--border);
  color: var(--text);
  font-size: 20px;
  padding: 4px 10px;
  border-radius: 6px;
  cursor: pointer;
}

.topbar .current-lesson {
  font-family: var(--mono);
  font-size: 14px;
  color: var(--text-muted);
  margin-left: auto;
}

/* ============ SIDEBAR / TIMELINE ============ */
.sidebar {
  position: fixed;
  top: 58px;
  bottom: 0;
  left: 0;
  width: var(--sidebar-w);
  background: var(--bg-elevated);
  border-right: 1px solid var(--border);
  overflow-y: auto;
  padding: 16px 12px 40px;
}

.sidebar h3 {
  font-size: 11px;
  text-transform: uppercase;
  letter-spacing: 1.2px;
  color: var(--text-muted);
  margin: 18px 8px 8px;
}

.sidebar h3:first-child {
  margin-top: 4px;
}

.timeline-group {
  margin-bottom: 6px;
}

.timeline-group .group-label {
  display: block;
  width: 100%;
  text-align: left;
  background: none;
  border: none;
  color: var(--text-muted);
  font-size: 12px;
  font-weight: 600;
  padding: 8px 10px;
  cursor: pointer;
  border-radius: 6px;
  font-family: var(--sans);
}

.timeline-group .group-label:hover {
  background: var(--bg-hover);
  color: var(--text);
}

.timeline-group .group-label .caret {
  display: inline-block;
  transition: transform 0.15s ease;
  margin-right: 6px;
  color: var(--text-muted);
  font-size: 10px;
}

.timeline-group.open .group-label .caret {
  transform: rotate(90deg);
}

.timeline-group .lessons {
  list-style: none;
  margin-left: 10px;
  overflow: hidden;
  max-height: 0;
  transition: max-height 0.25s ease;
}

.timeline-group.open .lessons {
  max-height: 600px;
}

.timeline-group .lessons a {
  display: block;
  padding: 6px 10px;
  border-radius: 6px;
  text-decoration: none;
  color: var(--text-muted);
  font-size: 13.5px;
  font-family: var(--mono);
  border-left: 2px solid transparent;
  transition: background 0.12s, color 0.12s, border-color 0.12s;
}

.timeline-group .lessons a .num {
  color: var(--accent);
  margin-right: 6px;
  opacity: 0.7;
}

.timeline-group .lessons a:hover {
  background: var(--bg-hover);
  color: var(--text);
}

.timeline-group .lessons a.active {
  background: var(--bg-hover);
  color: var(--text);
  border-left-color: var(--accent);
  font-weight: 600;
}

.timeline-group .lessons a.active .num {
  color: var(--accent);
  opacity: 1;
}

/* ============ MAIN CONTENT ============ */
.main {
  grid-column: 2;
  padding: 78px 0 60px;
  max-width: 860px;
}

.lesson {
  padding: 20px 24px 40px;
  border-bottom: 1px solid var(--border);
  scroll-margin-top: 70px;
}

.lesson:last-child {
  border-bottom: none;
}

.lesson-header {
  margin-bottom: 28px;
}

.lesson-header .eyebrow {
  font-family: var(--mono);
  font-size: 13px;
  color: var(--accent);
  letter-spacing: 0.4px;
}

.lesson-header h1 {
  font-size: 30px;
  font-weight: 700;
  margin-top: 6px;
  line-height: 1.2;
}

.lesson-header .subtitle {
  color: var(--text-muted);
  margin-top: 8px;
}

.lesson-header .meta {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
  margin-top: 16px;
}

.meta-pill {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  background: var(--bg-elevated);
  border: 1px solid var(--border);
  border-radius: 20px;
  padding: 4px 12px;
  font-size: 12.5px;
  color: var(--text-muted);
}

.meta-pill .dot {
  width: 8px;
  height: 8px;
  border-radius: 50%;
  display: inline-block;
}

.dot-theory { background: var(--accent-purple); }
.dot-demo { background: var(--accent-green); }
.dot-task { background: var(--accent-yellow); }

/* Section headings inside lesson */
.lesson h2 {
  font-size: 22px;
  font-weight: 700;
  margin: 34px 0 14px;
  padding-bottom: 8px;
  border-bottom: 1px solid var(--border);
  display: flex;
  align-items: center;
  gap: 10px;
}

.lesson h2 .sec-num {
  font-family: var(--mono);
  font-size: 14px;
  color: var(--accent);
  background: var(--bg-elevated);
  border: 1px solid var(--border);
  border-radius: 6px;
  padding: 2px 8px;
}

.lesson h3 {
  font-size: 17px;
  font-weight: 600;
  margin: 22px 0 10px;
  color: var(--accent-yellow);
}

.lesson p {
  margin: 10px 0;
  color: var(--text);
}

.lesson p.lead {
  font-size: 18px;
  color: var(--text);
}

.lesson ul, .lesson ol {
  margin: 10px 0 10px 24px;
}

.lesson li {
  margin: 6px 0;
}

.lesson a {
  color: var(--accent);
}

.lesson code {
  font-family: var(--mono);
  background: var(--bg-elevated);
  border: 1px solid var(--border);
  border-radius: 4px;
  padding: 1px 6px;
  font-size: 0.92em;
  color: var(--accent-green);
}

.lesson pre {
  background: var(--bg-elevated);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 14px 16px;
  overflow-x: auto;
  margin: 12px 0;
}

.lesson pre code {
  background: none;
  border: none;
  padding: 0;
  color: var(--text);
  font-size: 14px;
  line-height: 1.6;
}

/* Highlighted note boxes */
.callout {
  border-left: 3px solid var(--accent);
  background: var(--bg-elevated);
  border-radius: 0 var(--radius) var(--radius) 0;
  padding: 12px 16px;
  margin: 16px 0;
}

.callout.info { border-left-color: var(--accent); }
.callout.warn { border-left-color: var(--accent-yellow); }
.callout.danger { border-left-color: var(--accent-red); }

.callout .callout-title {
  font-weight: 700;
  font-size: 13px;
  text-transform: uppercase;
  letter-spacing: 0.6px;
  margin-bottom: 4px;
}

.callout.info .callout-title { color: var(--accent); }
.callout.warn .callout-title { color: var(--accent-yellow); }
.callout.danger .callout-title { color: var(--accent-red); }

/* ============ TERMINAL BLOCKS ============ */
.term {
  background: var(--terminal-bg);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  margin: 16px 0;
  overflow: hidden;
  font-family: var(--mono);
}

.term .term-bar {
  display: flex;
  align-items: center;
  gap: 6px;
  padding: 8px 14px;
  background: var(--bg-elevated);
  border-bottom: 1px solid var(--border);
}

.term .term-bar .dot {
  width: 12px;
  height: 12px;
  border-radius: 50%;
}

.term .term-bar .dot.r { background: #ff5f57; }
.term .term-bar .dot.y { background: #febc2e; }
.term .term-bar .dot.g { background: #28c840; }

.term .term-bar .term-title {
  margin-left: 10px;
  font-size: 12.5px;
  color: var(--text-muted);
}

.term .term-body {
  padding: 16px 18px;
  font-size: 14px;
  line-height: 1.7;
  overflow-x: auto;
  white-space: pre;
}

.term .term-body .prompt {
  color: var(--accent-green);
}

.term .term-body .cmd {
  color: #e6edf3;
  font-weight: 600;
}

.term .term-body .out {
  color: #c9d1d9;
}

.term .term-body .out .comment {
  color: var(--text-muted);
  font-style: italic;
}

.term .term-body .out .path {
  color: var(--accent);
}

.term .term-body .out .dir {
  color: var(--accent);
  font-weight: 700;
}

.term .term-body .out .err {
  color: var(--accent-red);
}

/* Diff styling */
.term .diff-add {
  color: var(--accent-green);
}

.term .term-cursor::after {
  content: "▋";
  color: var(--accent-green);
  animation: blink 1s step-start infinite;
}

@keyframes blink {
  50% { opacity: 0; }
}

/* ============ TABLES ============ */
.table-wrap {
  overflow-x: auto;
  margin: 16px 0;
  border: 1px solid var(--border);
  border-radius: var(--radius);
}

table.lesson-table {
  width: 100%;
  border-collapse: collapse;
  font-size: 14.5px;
}

.lesson-table th {
  background: var(--bg-elevated);
  text-align: left;
  padding: 10px 14px;
  font-weight: 600;
  border-bottom: 1px solid var(--border);
  white-space: nowrap;
}

.lesson-table td {
  padding: 10px 14px;
  border-bottom: 1px solid var(--border);
  vertical-align: top;
}

.lesson-table tr:last-child td {
  border-bottom: none;
}

.lesson-table td code, .lesson-table th code {
  font-size: 0.9em;
}

.lesson-table tr:hover td {
  background: var(--bg-hover);
}

/* ============ HOMEWORK ============ */
.homework {
  margin-top: 40px;
  border: 1px solid var(--accent-green);
  border-radius: var(--radius);
  background: rgba(63, 185, 80, 0.06);
  padding: 20px 22px;
}

.homework .homework-title {
  font-weight: 700;
  color: var(--accent-green);
  font-size: 16px;
  display: flex;
  align-items: center;
  gap: 8px;
  margin-bottom: 10px;
}

.homework ol {
  margin-left: 20px;
}

/* ============ PREV/NEXT ============ */
.lesson-nav {
  display: flex;
  justify-content: space-between;
  gap: 16px;
  padding: 30px 24px 10px;
  max-width: 860px;
}

.lesson-nav a {
  text-decoration: none;
  background: var(--bg-elevated);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 14px 18px;
  max-width: 48%;
  transition: border-color 0.15s, background 0.15s;
}

.lesson-nav a:hover {
  border-color: var(--accent);
  background: var(--bg-hover);
}

.lesson-nav .nav-label {
  font-size: 12px;
  color: var(--text-muted);
  text-transform: uppercase;
  letter-spacing: 0.6px;
}

.lesson-nav .nav-title {
  font-size: 15px;
  color: var(--text);
  margin-top: 4px;
  font-weight: 600;
}

.lesson-nav .next {
  text-align: right;
  margin-left: auto;
}

/* ============ KEYBOARD KEYS ============ */
kbd {
  font-family: var(--mono);
  background: var(--bg-elevated);
  border: 1px solid var(--border-light);
  border-bottom-width: 3px;
  border-radius: 4px;
  padding: 1px 7px;
  font-size: 0.82em;
  color: var(--text);
}

/* ============ RESPONSIVE ============ */
@media (max-width: 900px) {
  .layout {
    grid-template-columns: 1fr;
  }

  .sidebar {
    display: none;
    position: fixed;
    top: 58px;
    left: 0;
    right: 0;
    bottom: 0;
    width: 100%;
    z-index: 90;
  }

  .sidebar.open {
    display: block;
  }

  .topbar .hamburger {
    display: block;
  }

  .main {
    grid-column: 1;
    padding: 74px 0 40px;
  }

  .topbar .current-lesson {
    display: none;
  }
}

@media (min-width: 901px) {
  .hamburger-backdrop {
    display: none;
  }
}