/* ===== Terminal Theme — CLI Mastery ===== */

:root {
  --bg: #0d1117;
  --bg-soft: #161b22;
  --bg-elev: #1c2128;
  --border: #30363d;
  --text: #c9d1d9;
  --text-dim: #8b949e;
  --green: #3fb950;
  --green-bright: #56d364;
  --cyan: #79c0ff;
  --yellow: #d29922;
  --orange: #ffa657;
  --red: #f85149;
  --purple: #d2a8ff;
  --prompt: #58a6ff;
  --shadow: 0 0 24px rgba(63, 185, 80, 0.08);
}

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

html { scroll-behavior: smooth; }

body {
  background: var(--bg);
  color: var(--text);
  font-family: 'JetBrains Mono', 'Fira Code', 'Menlo', 'Consolas', monospace;
  font-size: 15px;
  line-height: 1.7;
  min-height: 100vh;
  background-image:
    radial-gradient(circle at 20% 0%, rgba(63, 185, 80, 0.05), transparent 40%),
    radial-gradient(circle at 80% 100%, rgba(88, 166, 255, 0.05), transparent 40%);
}

/* ===== Header / Nav ===== */
header {
  background: var(--bg-soft);
  border-bottom: 1px solid var(--border);
  padding: 16px 32px;
  position: sticky;
  top: 0;
  z-index: 100;
  backdrop-filter: blur(10px);
}

nav {
  max-width: 1200px;
  margin: 0 auto;
  display: flex;
  justify-content: space-between;
  align-items: center;
  flex-wrap: wrap;
  gap: 16px;
}

.logo {
  font-weight: 700;
  font-size: 18px;
  color: var(--green);
}
.logo::before { content: "▶ "; color: var(--green-bright); }

nav ul {
  list-style: none;
  display: flex;
  gap: 20px;
  flex-wrap: wrap;
}

nav a {
  color: var(--text-dim);
  text-decoration: none;
  transition: color 0.15s ease;
  font-size: 14px;
}
nav a:hover, nav a.active { color: var(--green-bright); }

/* ===== Main container ===== */
main {
  max-width: 1100px;
  margin: 0 auto;
  padding: 40px 32px 80px;
}

/* ===== Hero ===== */
.hero {
  background: var(--bg-soft);
  border: 1px solid var(--border);
  border-radius: 8px;
  padding: 48px 40px;
  margin-bottom: 40px;
  box-shadow: var(--shadow);
  position: relative;
  overflow: hidden;
}
.hero::before {
  content: "";
  position: absolute;
  top: 0; left: 0; right: 0;
  height: 32px;
  background: var(--bg-elev);
  border-bottom: 1px solid var(--border);
}
.hero::after {
  content: "● ● ●";
  position: absolute;
  top: 4px;
  left: 14px;
  color: var(--red);
  letter-spacing: 6px;
  font-size: 12px;
}
.hero-content { padding-top: 24px; }
.hero h1 {
  font-size: 32px;
  color: var(--green-bright);
  margin-bottom: 12px;
}
.hero h1::before { content: "$ "; color: var(--prompt); }
.hero p {
  color: var(--text-dim);
  font-size: 15px;
  max-width: 720px;
}

/* ===== Sections ===== */
section { margin-bottom: 48px; }

h2 {
  color: var(--green-bright);
  font-size: 22px;
  margin-bottom: 20px;
  border-bottom: 1px dashed var(--border);
  padding-bottom: 8px;
}
h2::before { content: "## "; color: var(--text-dim); }

h3 {
  color: var(--cyan);
  font-size: 18px;
  margin: 28px 0 12px;
}
h3::before { content: "### "; color: var(--text-dim); }

p { margin-bottom: 14px; }

a { color: var(--prompt); text-decoration: none; }
a:hover { text-decoration: underline; }

ul, ol { margin: 12px 0 16px 24px; }
li { margin-bottom: 6px; }

strong { color: var(--orange); font-weight: 600; }
em { color: var(--purple); font-style: normal; }

/* ===== Code blocks ===== */
code {
  background: var(--bg-elev);
  color: var(--green-bright);
  padding: 2px 6px;
  border-radius: 4px;
  font-size: 13px;
  border: 1px solid var(--border);
}

pre {
  background: var(--bg-elev);
  border: 1px solid var(--border);
  border-radius: 6px;
  padding: 16px 20px;
  overflow-x: auto;
  margin: 16px 0;
  position: relative;
}
pre code {
  background: none;
  border: none;
  padding: 0;
  color: var(--text);
  font-size: 13.5px;
  line-height: 1.6;
}
pre .prompt { color: var(--green); user-select: none; }
pre .comment { color: var(--text-dim); font-style: italic; }
pre .output { color: var(--text-dim); }
pre .flag { color: var(--orange); }
pre .cmd { color: var(--cyan); }

.copy-btn {
  position: absolute;
  top: 8px;
  right: 8px;
  background: var(--bg-soft);
  color: var(--text-dim);
  border: 1px solid var(--border);
  border-radius: 4px;
  padding: 4px 10px;
  font-family: inherit;
  font-size: 11px;
  cursor: pointer;
  transition: all 0.15s ease;
  opacity: 0;
}
pre:hover .copy-btn { opacity: 1; }
.copy-btn:hover {
  color: var(--green-bright);
  border-color: var(--green);
}
.copy-btn.copied { color: var(--green-bright); border-color: var(--green); }

/* ===== Roadmap cards ===== */
.roadmap {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
  gap: 16px;
}

.card {
  background: var(--bg-soft);
  border: 1px solid var(--border);
  border-radius: 6px;
  padding: 20px;
  transition: all 0.2s ease;
  text-decoration: none !important;
  color: var(--text);
  display: block;
}
.card:hover {
  border-color: var(--green);
  transform: translateY(-2px);
  box-shadow: var(--shadow);
}
.card .chuong-num {
  color: var(--green);
  font-size: 12px;
  margin-bottom: 6px;
}
.card h3 {
  font-size: 16px;
  color: var(--text);
  margin: 0 0 8px;
}
.card h3::before { content: ""; }
.card p {
  color: var(--text-dim);
  font-size: 13px;
  margin: 0;
}
.card.locked { opacity: 0.5; cursor: not-allowed; }
.card.locked:hover { transform: none; border-color: var(--border); }

/* ===== Tables ===== */
table {
  width: 100%;
  border-collapse: collapse;
  margin: 16px 0;
  background: var(--bg-soft);
  border: 1px solid var(--border);
  border-radius: 6px;
  overflow: hidden;
}
th, td {
  padding: 10px 14px;
  text-align: left;
  border-bottom: 1px solid var(--border);
  font-size: 14px;
}
th { background: var(--bg-elev); color: var(--cyan); font-weight: 600; }
tr:last-child td { border-bottom: none; }
tr:hover td { background: var(--bg-elev); }

/* ===== Callouts ===== */
.callout {
  border-left: 3px solid var(--cyan);
  background: var(--bg-soft);
  padding: 14px 18px;
  margin: 18px 0;
  border-radius: 0 6px 6px 0;
}
.callout.warn { border-color: var(--yellow); }
.callout.danger { border-color: var(--red); }
.callout.tip { border-color: var(--green); }
.callout-title {
  font-weight: 600;
  margin-bottom: 6px;
}
.callout.warn .callout-title { color: var(--yellow); }
.callout.danger .callout-title { color: var(--red); }
.callout.tip .callout-title { color: var(--green-bright); }
.callout.info .callout-title { color: var(--cyan); }

/* ===== Terminal Simulator ===== */
.terminal-sim {
  background: #000;
  border: 1px solid var(--border);
  border-radius: 8px;
  padding: 0;
  margin: 24px 0;
  overflow: hidden;
  box-shadow: 0 4px 20px rgba(0,0,0,0.4);
}
.terminal-header {
  background: var(--bg-elev);
  padding: 8px 14px;
  border-bottom: 1px solid var(--border);
  display: flex;
  align-items: center;
  gap: 8px;
}
.terminal-header .dot {
  width: 12px;
  height: 12px;
  border-radius: 50%;
  display: inline-block;
}
.terminal-header .dot.red { background: #ff5f56; }
.terminal-header .dot.yellow { background: #ffbd2e; }
.terminal-header .dot.green { background: #27c93f; }
.terminal-header .title {
  flex: 1;
  text-align: center;
  font-size: 12px;
  color: var(--text-dim);
}
.terminal-body {
  padding: 16px 18px;
  min-height: 280px;
  max-height: 420px;
  overflow-y: auto;
  font-size: 13.5px;
  line-height: 1.6;
}
.terminal-body .line { white-space: pre-wrap; word-break: break-all; }
.terminal-body .prompt { color: var(--green); }
.terminal-body .output { color: var(--text); }
.terminal-body .err { color: var(--red); }
.terminal-input-line {
  display: flex;
  align-items: center;
  padding: 0 18px 16px;
}
.terminal-input-line .prompt { color: var(--green); margin-right: 8px; }
.terminal-input {
  flex: 1;
  background: transparent;
  border: none;
  outline: none;
  color: var(--text);
  font-family: inherit;
  font-size: 13.5px;
  caret-color: var(--green-bright);
}

/* ===== Quiz ===== */
.quiz {
  background: var(--bg-soft);
  border: 1px solid var(--border);
  border-radius: 8px;
  padding: 24px;
  margin: 32px 0;
}
.quiz h3 { margin-top: 0; }
.quiz-question { margin-bottom: 20px; }
.quiz-question .q-text {
  font-weight: 600;
  margin-bottom: 10px;
  color: var(--text);
}
.quiz-options { display: flex; flex-direction: column; gap: 8px; }
.quiz-option {
  background: var(--bg-elev);
  border: 1px solid var(--border);
  color: var(--text);
  padding: 10px 14px;
  border-radius: 4px;
  text-align: left;
  cursor: pointer;
  font-family: inherit;
  font-size: 13.5px;
  transition: all 0.15s ease;
}
.quiz-option:hover:not(.disabled) { border-color: var(--cyan); background: var(--bg); }
.quiz-option.correct {
  background: rgba(63, 185, 80, 0.15);
  border-color: var(--green);
  color: var(--green-bright);
}
.quiz-option.wrong {
  background: rgba(248, 81, 73, 0.12);
  border-color: var(--red);
  color: var(--red);
}
.quiz-option.disabled { cursor: default; }
.quiz-feedback {
  margin-top: 8px;
  font-size: 13px;
  color: var(--text-dim);
}
.quiz-score {
  margin-top: 20px;
  padding: 16px;
  background: var(--bg-elev);
  border-radius: 6px;
  border: 1px solid var(--border);
  text-align: center;
  font-size: 16px;
  display: none;
}
.quiz-score.show { display: block; }
.quiz-score .num { color: var(--green-bright); font-weight: 700; }

/* ===== Footer / Pagination ===== */
.lesson-nav {
  display: flex;
  justify-content: space-between;
  margin-top: 60px;
  padding-top: 24px;
  border-top: 1px solid var(--border);
  gap: 16px;
}
.lesson-nav a {
  background: var(--bg-soft);
  border: 1px solid var(--border);
  padding: 12px 20px;
  border-radius: 6px;
  color: var(--text);
  font-size: 14px;
}
.lesson-nav a:hover { border-color: var(--green); text-decoration: none; }
.lesson-nav a.disabled { opacity: 0.4; pointer-events: none; }
.lesson-nav .label { color: var(--text-dim); font-size: 11px; display: block; }

footer {
  text-align: center;
  padding: 40px 20px;
  color: var(--text-dim);
  font-size: 12px;
  border-top: 1px solid var(--border);
  margin-top: 60px;
}

/* ===== Responsive ===== */
@media (max-width: 720px) {
  body { font-size: 14px; }
  main { padding: 24px 16px 60px; }
  .hero { padding: 40px 20px 32px; }
  .hero h1 { font-size: 22px; }
  nav ul { gap: 12px; font-size: 12px; }
  header { padding: 12px 16px; }
}

/* ===== Scrollbar ===== */
::-webkit-scrollbar { width: 10px; height: 10px; }
::-webkit-scrollbar-track { background: var(--bg); }
::-webkit-scrollbar-thumb { background: var(--border); border-radius: 5px; }
::-webkit-scrollbar-thumb:hover { background: var(--text-dim); }

/* ===== Floating Terminal Button ===== */
.floating-terminal-btn {
  position: fixed;
  bottom: 24px;
  right: 24px;
  z-index: 200;
  background: linear-gradient(135deg, #1f2933 0%, #0d1117 100%);
  color: var(--green-bright);
  border: 1px solid var(--green);
  border-radius: 999px;
  padding: 12px 18px;
  font-family: inherit;
  font-size: 13px;
  font-weight: 600;
  cursor: pointer;
  display: flex;
  align-items: center;
  gap: 10px;
  box-shadow: 0 6px 20px rgba(63, 185, 80, 0.25), 0 2px 6px rgba(0, 0, 0, 0.4);
  transition: all 0.2s ease;
}
.floating-terminal-btn:hover {
  transform: translateY(-2px);
  box-shadow: 0 10px 26px rgba(63, 185, 80, 0.4), 0 4px 10px rgba(0, 0, 0, 0.5);
  border-color: var(--green-bright);
}
.floating-terminal-btn:active { transform: translateY(0); }
.floating-terminal-btn .ft-icon {
  font-family: inherit;
  letter-spacing: 1px;
  animation: blink 1.2s infinite step-end;
}
.floating-terminal-btn .ft-shortcut {
  background: rgba(255, 255, 255, 0.08);
  color: var(--text-dim);
  border: 1px solid var(--border);
  border-radius: 4px;
  padding: 2px 6px;
  font-size: 10px;
  font-weight: 500;
}
@keyframes blink {
  50% { opacity: 0.4; }
}

/* ===== Terminal Modal ===== */
.terminal-modal-overlay {
  position: fixed;
  inset: 0;
  background: rgba(0, 0, 0, 0.7);
  backdrop-filter: blur(6px);
  z-index: 300;
  display: flex;
  align-items: center;
  justify-content: center;
  padding: 24px;
  opacity: 0;
  pointer-events: none;
  transition: opacity 0.2s ease;
}
.terminal-modal-overlay.open {
  opacity: 1;
  pointer-events: auto;
}
.terminal-modal {
  width: min(900px, 100%);
  max-height: min(640px, 90vh);
  transform: scale(0.94) translateY(8px);
  transition: transform 0.2s ease;
  display: flex;
  flex-direction: column;
}
.terminal-modal-overlay.open .terminal-modal {
  transform: scale(1) translateY(0);
}
.terminal-modal .terminal-sim {
  margin: 0;
  width: 100%;
  display: flex;
  flex-direction: column;
  flex: 1;
  min-height: 480px;
  box-shadow: 0 20px 60px rgba(0, 0, 0, 0.6), 0 0 40px rgba(63, 185, 80, 0.1);
  border-color: var(--green);
}
.terminal-modal .terminal-body {
  flex: 1;
  max-height: none;
  min-height: 360px;
}
.terminal-modal .terminal-header {
  position: relative;
}
.terminal-close {
  margin-left: auto;
  background: transparent;
  border: none;
  color: var(--text-dim);
  font-size: 14px;
  cursor: pointer;
  padding: 4px 8px;
  border-radius: 4px;
  font-family: inherit;
  transition: all 0.15s ease;
}
.terminal-close:hover {
  background: rgba(248, 81, 73, 0.15);
  color: var(--red);
}
.terminal-modal .terminal-header .dot[data-action="close"] {
  cursor: pointer;
}
.terminal-modal .terminal-header .dot[data-action="close"]:hover {
  filter: brightness(1.3);
}
body.modal-open { overflow: hidden; }

@media (max-width: 720px) {
  .floating-terminal-btn { bottom: 16px; right: 16px; padding: 10px 14px; }
  .floating-terminal-btn .ft-label { display: none; }
  .terminal-modal-overlay { padding: 12px; }
  .terminal-modal .terminal-sim { min-height: 360px; }
}

/* ===== Utility ===== */
.text-dim { color: var(--text-dim); }
.text-green { color: var(--green-bright); }
.text-cyan { color: var(--cyan); }
.text-orange { color: var(--orange); }
.center { text-align: center; }
.mt-2 { margin-top: 16px; }
.mt-4 { margin-top: 32px; }