/* ==========================================================================
   CS210 standalone-page design system
   Shared by every hand-written page under
   /academics/computer-science/cs210/ -- the three exam banks and the twelve
   study guides / cheat sheets.

   Theme comes from html[data-theme="light|dark"], which the site's toggle
   sets. The pages used to theme themselves with @media (prefers-color-scheme)
   or a hand-appended html[data-theme='dark'] patch block, so the toggle either
   did nothing or fought a wall of !important overrides. Everything here
   resolves from a token, in both directions, with no !important anywhere.
   ========================================================================== */

:root {
  color-scheme: light;

  --bg: #f4f6fc;
  --bg-tint-a: rgba(59, 111, 232, 0.1);
  --bg-tint-b: rgba(124, 92, 252, 0.07);

  --surface: #ffffff;
  --surface2: #f1f3fa;
  --surface3: #e7eaf5;
  --inset: #f8f9fd;

  --text: #141a29;
  --text2: #4c5570;
  --muted: #656e8a;

  --border: #e2e6f0;
  --border2: #cfd5e6;

  --accent: #3b6fe8;
  --accent2: #7c5cfc;
  --accent-ink: #2b57c4;
  --accent-soft: rgba(59, 111, 232, 0.09);
  --accent-line: rgba(59, 111, 232, 0.28);
  --on-accent: #ffffff;

  --green: #0f9d58;
  --green-ink: #0b7a44;
  --green-soft: rgba(15, 157, 88, 0.1);
  --green-line: rgba(15, 157, 88, 0.32);

  --red: #dc3d4f;
  --red-ink: #bb2536;
  --red-soft: rgba(220, 61, 79, 0.09);
  --red-line: rgba(220, 61, 79, 0.3);

  --yellow: #b5790d;
  --yellow-ink: #91600a;
  --yellow-soft: rgba(214, 148, 32, 0.13);
  --yellow-line: rgba(214, 148, 32, 0.34);

  --violet-ink: #6b3fd4;
  --violet-soft: rgba(124, 92, 252, 0.1);
  --violet-line: rgba(124, 92, 252, 0.28);

  --code-bg: #f6f7fc;
  --code-color: #2b3350;
  --code-keyword: #8250df;
  --code-string: #0a7d55;
  --code-comment: #7a839d;
  --code-type: #b5790d;
  --code-function: #2b57c4;

  --shadow-sm: 0 1px 2px rgba(20, 26, 41, 0.05);
  --shadow:
    0 6px 20px -8px rgba(20, 26, 41, 0.16),
    0 2px 6px -2px rgba(20, 26, 41, 0.06);
  --shadow-lg:
    0 24px 60px -24px rgba(20, 26, 41, 0.28),
    0 6px 18px -10px rgba(20, 26, 41, 0.1);
  --shadow-accent: 0 12px 28px -12px rgba(59, 111, 232, 0.5);

  --progress-bg: rgba(244, 246, 252, 0.88);

  --r-sm: 8px;
  --r-md: 12px;
  --r-lg: 18px;
  --r-xl: 26px;

  --ease: cubic-bezier(0.22, 0.61, 0.36, 1);
  --dur: 220ms;

  --sans:
    "Inter", -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto,
    "Helvetica Neue", Arial, sans-serif;
  --mono: ui-monospace, SFMono-Regular, "SF Mono", Menlo, Consolas, monospace;

  --page-w: 980px;
}

html[data-theme="dark"] {
  color-scheme: dark;

  --bg: #080b12;
  --bg-tint-a: rgba(96, 140, 255, 0.15);
  --bg-tint-b: rgba(150, 120, 255, 0.1);

  --surface: #111725;
  --surface2: #171e2f;
  --surface3: #1f273c;
  --inset: #141a28;

  --text: #e7ecf8;
  --text2: #a3adc6;
  --muted: #7b859e;

  --border: #232c42;
  --border2: #303b56;

  --accent: #7ea6ff;
  --accent2: #b09bff;
  --accent-ink: #a3c0ff;
  --accent-soft: rgba(126, 166, 255, 0.13);
  --accent-line: rgba(126, 166, 255, 0.32);
  --on-accent: #0a1020;

  --green: #3ecf8e;
  --green-ink: #6fe7b2;
  --green-soft: rgba(62, 207, 142, 0.13);
  --green-line: rgba(62, 207, 142, 0.32);

  --red: #ff6b7d;
  --red-ink: #ff97a4;
  --red-soft: rgba(255, 107, 125, 0.13);
  --red-line: rgba(255, 107, 125, 0.3);

  --yellow: #e0a83c;
  --yellow-ink: #f2c76d;
  --yellow-soft: rgba(224, 168, 60, 0.14);
  --yellow-line: rgba(224, 168, 60, 0.32);

  --violet-ink: #c3b0ff;
  --violet-soft: rgba(176, 155, 255, 0.13);
  --violet-line: rgba(176, 155, 255, 0.3);

  --code-bg: #0d1220;
  --code-color: #cfd8ee;
  --code-keyword: #c4a6ff;
  --code-string: #7bdcb0;
  --code-comment: #6f7994;
  --code-type: #f0c46b;
  --code-function: #8fb6ff;

  --shadow-sm: 0 1px 2px rgba(0, 0, 0, 0.4);
  --shadow:
    0 8px 24px -10px rgba(0, 0, 0, 0.7), 0 2px 6px -2px rgba(0, 0, 0, 0.4);
  --shadow-lg:
    0 30px 70px -30px rgba(0, 0, 0, 0.85), 0 8px 20px -12px rgba(0, 0, 0, 0.6);
  --shadow-accent: 0 12px 30px -14px rgba(126, 166, 255, 0.55);

  --progress-bg: rgba(8, 11, 18, 0.86);
}

/* --------------------------------------------------------------- base --- */

*,
*::before,
*::after {
  box-sizing: border-box;
}

html {
  -webkit-text-size-adjust: 100%;
  scroll-behavior: smooth;
}

body {
  margin: 0;
  padding: 0 0 clamp(48px, 8vw, 96px);
  min-height: 100vh;
  background-color: var(--bg);
  background-image:
    radial-gradient(64rem 42rem at 10% -14%, var(--bg-tint-a), transparent 62%),
    radial-gradient(52rem 36rem at 94% 2%, var(--bg-tint-b), transparent 60%);
  background-attachment: fixed;
  color: var(--text);
  font-family: var(--sans);
  font-size: 15px;
  line-height: 1.65;
  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility;
  transition:
    background-color var(--dur) var(--ease),
    color var(--dur) var(--ease);
}

h1,
h2,
h3,
h4,
h5,
h6 {
  margin: 0 0 0.5em;
  line-height: 1.25;
  letter-spacing: -0.015em;
  font-weight: 650;
  color: var(--text);
}

h2 {
  font-size: 1.35rem;
}

h3 {
  font-size: 1.1rem;
}

h4 {
  font-size: 0.97rem;
}

p {
  margin: 0 0 0.85em;
}

p:last-child {
  margin-bottom: 0;
}

ul,
ol {
  margin: 0 0 0.85em;
  padding-left: 1.35em;
}

li {
  margin-bottom: 0.35em;
}

li:last-child {
  margin-bottom: 0;
}

a {
  color: var(--accent-ink);
  text-decoration-color: var(--accent-line);
  text-underline-offset: 2px;
  transition: color 160ms var(--ease);
}

a:hover {
  color: var(--accent);
}

strong,
b {
  color: var(--text);
  font-weight: 650;
}

hr {
  height: 1px;
  margin: 24px 0;
  border: 0;
  background: var(--border);
}

img {
  max-width: 100%;
  height: auto;
}

::selection {
  background: var(--accent-soft);
  color: var(--text);
}

:focus-visible {
  outline: 2px solid var(--accent);
  outline-offset: 2px;
}

::placeholder {
  color: var(--muted);
}

/* --------------------------------------------------------------- shell -- */

.container,
.content,
.main-content {
  max-width: var(--page-w);
  margin: 0 auto;
  padding: 0;
  background: none;
  border-radius: 0;
  box-shadow: none;
}

.container {
  padding: 0 clamp(14px, 4vw, 28px);
}

.content,
.main-content {
  max-width: none;
}

header {
  position: relative;
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 11px;
  margin: 0 0 clamp(22px, 3vw, 34px);
  padding: clamp(30px, 5vw, 52px) clamp(18px, 4vw, 32px) clamp(26px, 4vw, 40px);
  background:
    linear-gradient(150deg, var(--bg-tint-a), transparent 58%), var(--surface);
  border-bottom: 1px solid var(--border);
  text-align: center;
  overflow: hidden;
  animation: cs-rise 520ms var(--ease) both;
}

header::after {
  content: "";
  position: absolute;
  inset: auto 0 0 0;
  height: 2px;
  background: linear-gradient(
    90deg,
    transparent,
    var(--accent),
    var(--accent2),
    transparent
  );
}

/* Guides put their header inside .container; let it run edge to edge the way
   the exam headers (direct body children) already do. */
.container > header {
  width: 100vw;
  margin-inline: calc(50% - 50vw);
}

/* The header is a centred column, so its children hand spacing to the gap. */
header > * {
  margin-block: 0;
}

header h1 {
  max-width: 26ch;
  margin: 0;
  font-size: clamp(1.55rem, 1.05rem + 2.2vw, 2.35rem);
  font-weight: 700;
  letter-spacing: -0.028em;
}

header h1 span {
  color: var(--accent-ink);
}

header p {
  max-width: 62ch;
  margin: 0;
  color: var(--text2);
  font-size: 0.95rem;
}

.subtitle {
  color: var(--text2);
  font-size: 0.95rem;
}

body[data-cs210-page="hash-tables"] .container > h1:first-of-type,
body[data-cs210-page="merge-sort"] .container > h1:first-of-type {
  margin: clamp(30px, 5vw, 52px) 0 0;
  font-size: clamp(1.55rem, 1.05rem + 2.2vw, 2.35rem);
  font-weight: 700;
  letter-spacing: -0.028em;
  text-align: center;
}

body[data-cs210-page="hash-tables"] .container > .subtitle,
body[data-cs210-page="merge-sort"] .container > .subtitle {
  margin: 0 0 clamp(24px, 4vw, 38px);
  padding-bottom: clamp(20px, 3vw, 30px);
  border-bottom: 1px solid var(--border);
  text-align: center;
}

section,
.section {
  margin: 0 0 clamp(20px, 3vw, 30px);
  padding: clamp(20px, 2.6vw, 30px);
  border: 1px solid var(--border);
  border-radius: var(--r-lg);
  background: var(--surface);
  box-shadow: var(--shadow-sm);
  animation: cs-rise 520ms var(--ease) both;
}

section > h2:first-child,
.section > h2:first-child,
.card > h2:first-child {
  display: flex;
  align-items: baseline;
  gap: 10px;
  margin-bottom: 0.7em;
  padding-bottom: 0.55em;
  border-bottom: 1px solid var(--border);
}

.section-anchor {
  display: block;
  height: 0;
  scroll-margin-top: 80px;
}

footer,
.footer {
  max-width: var(--page-w);
  margin: 32px auto 0;
  padding: 20px clamp(14px, 4vw, 28px) 0;
  border-top: 1px solid var(--border);
  color: var(--muted);
  font-size: 0.85rem;
  text-align: center;
}

/* ---------------------------------------------------------- navigation -- */

.nav,
nav,
.toc,
.menu {
  margin: 0 0 clamp(20px, 3vw, 30px);
  padding: clamp(16px, 2.2vw, 22px);
  border: 1px solid var(--border);
  border-radius: var(--r-lg);
  background: var(--surface);
  box-shadow: var(--shadow-sm);
  animation: cs-rise 520ms var(--ease) both;
}

.toc h2,
.toc h3,
.sidebar h2 {
  margin: 0 0 12px;
  color: var(--muted);
  font-size: 0.72rem;
  font-weight: 700;
  letter-spacing: 0.14em;
  text-transform: uppercase;
}

.nav ul,
nav ul,
.toc ul {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(210px, 1fr));
  gap: 6px;
  margin: 0;
  padding: 0;
  list-style: none;
}

.toc li,
.nav li,
nav li {
  margin: 0;
}

.nav a,
nav a,
.toc a,
.menu-item {
  display: block;
  padding: 8px 12px;
  border: 1px solid transparent;
  border-radius: var(--r-sm);
  color: var(--text2);
  font-size: 0.88rem;
  font-weight: 550;
  text-decoration: none;
  transition:
    background-color 160ms var(--ease),
    border-color 160ms var(--ease),
    color 160ms var(--ease),
    transform 160ms var(--ease);
}

.nav a:hover,
nav a:hover,
.toc a:hover,
.menu-item:hover {
  border-color: var(--accent-line);
  background: var(--accent-soft);
  color: var(--accent-ink);
  transform: translateX(2px);
}

.menu {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
  gap: 6px;
}

/* The tabbed cheat sheet keeps its section list in a rail. */
.sidebar {
  padding: 18px 16px;
  border: 1px solid var(--border);
  border-radius: var(--r-lg);
  background: var(--surface);
  box-shadow: var(--shadow-sm);
}

.nav-item {
  display: block;
  padding: 8px 12px;
  border: 1px solid transparent;
  border-radius: var(--r-sm);
  color: var(--text2);
  font-size: 0.86rem;
  font-weight: 550;
  text-decoration: none;
  cursor: pointer;
  transition:
    background-color 160ms var(--ease),
    border-color 160ms var(--ease),
    color 160ms var(--ease);
}

.nav-item:hover {
  background: var(--accent-soft);
  color: var(--accent-ink);
}

.nav-item.active {
  border-color: var(--accent-line);
  background: var(--accent-soft);
  color: var(--accent-ink);
  font-weight: 650;
}

[data-cs210-page="cheat-sheet-2"] body,
body[data-cs210-page="cheat-sheet-2"] {
  display: grid;
  grid-template-columns: minmax(190px, 240px) minmax(0, 1fr);
  gap: clamp(16px, 3vw, 30px);
  align-items: start;
  max-width: 1260px;
  margin: 0 auto;
  padding: clamp(56px, 7vw, 76px) clamp(14px, 3vw, 28px) 60px;
}

body[data-cs210-page="cheat-sheet-2"] .sidebar {
  position: sticky;
  top: 14px;
  max-height: calc(100vh - 28px);
  overflow-y: auto;
}

body[data-cs210-page="cheat-sheet-2"] .main-content {
  min-width: 0;
}

.topic-section {
  display: none;
}

.topic-section.active {
  display: block;
  animation: cs-fade 340ms var(--ease) both;
}

#scrollTop {
  position: fixed;
  right: 16px;
  bottom: 16px;
  z-index: 60;
  display: grid;
  place-items: center;
  width: 40px;
  height: 40px;
  border: 1px solid var(--border2);
  border-radius: 50%;
  background: var(--surface);
  color: var(--text2);
  box-shadow: var(--shadow);
  cursor: pointer;
  transition:
    transform 160ms var(--ease),
    border-color 160ms var(--ease);
}

#scrollTop:hover {
  transform: translateY(-2px);
  border-color: var(--accent-line);
  color: var(--accent-ink);
}

/* ------------------------------------------------------------ callouts -- */
/* One primitive: a tinted panel with a coloured spine. The variants below
   only change the accent, so a page can mix any of them and stay coherent. */

.definition,
.definition-box,
.example,
.example-box,
.important,
.important-box,
.note,
.tip,
.tip-box,
.key-point,
.key-concept,
.key-points,
.highlight,
.highlight-box,
.warning-box,
.danger-box,
.critical,
.complexity-warning,
.success,
.success-box,
.info,
.info-box,
.formula,
.algorithm,
.quote,
.hack,
.explanation,
.solution,
.operation-example {
  margin: 16px 0;
  padding: 15px 18px;
  border: 1px solid var(--border);
  border-left: 3px solid var(--accent);
  border-radius: var(--r-md);
  background: var(--surface2);
  color: var(--text2);
  font-size: 0.93rem;
}

.definition h3,
.definition h4,
.example h3,
.example h4,
.key-point h4,
.key-points h3,
.important h4,
.note strong,
.tip h4,
.solution h4,
.explanation h4,
.comparison-card h4,
.mini-card h4,
.rotation-card h4,
.complexity-card h4,
.pros h4,
.cons h4 {
  margin: 0 0 0.5em;
  color: var(--text);
  font-size: 0.88rem;
  font-weight: 700;
  letter-spacing: 0.02em;
}

.definition,
.definition-box,
.key-point,
.key-concept,
.key-points,
.explanation {
  border-left-color: var(--accent);
  background: var(--accent-soft);
}

.example,
.example-box,
.solution,
.operation-example,
.algorithm {
  border-left-color: var(--violet-ink);
  background: var(--violet-soft);
}

.note,
.info,
.info-box,
.quote,
.formula {
  border-left-color: var(--accent2);
  background: var(--surface2);
}

.tip,
.tip-box,
.success,
.success-box,
.hack {
  border-left-color: var(--green);
  background: var(--green-soft);
}

.important,
.important-box,
.highlight,
.highlight-box,
.warning-box,
.complexity-warning {
  border-left-color: var(--yellow);
  background: var(--yellow-soft);
}

.critical,
.danger-box {
  border-left-color: var(--red);
  background: var(--red-soft);
}

.formula {
  font-family: var(--mono);
  font-size: 0.88rem;
  color: var(--text);
}

.quote {
  font-style: italic;
}

.key-points ul,
.operations-list {
  margin: 0;
  padding-left: 1.15em;
}

.key-points li,
.operations-list li {
  margin-bottom: 0.4em;
}

.operations-list li strong {
  color: var(--text);
}

.algorithm-steps,
.operation-steps {
  counter-reset: step;
  margin: 12px 0 0;
  padding: 0;
  list-style: none;
}

.algorithm-steps li,
.operation-steps li {
  position: relative;
  margin-bottom: 8px;
  padding-left: 34px;
  color: var(--text2);
  font-size: 0.92rem;
}

.algorithm-steps li::before,
.operation-steps li::before {
  counter-increment: step;
  content: counter(step);
  position: absolute;
  left: 0;
  top: 1px;
  display: grid;
  place-items: center;
  width: 22px;
  height: 22px;
  border: 1px solid var(--accent-line);
  border-radius: 50%;
  background: var(--accent-soft);
  color: var(--accent-ink);
  font-size: 0.7rem;
  font-weight: 700;
}

.algorithm-step {
  margin-bottom: 8px;
  padding: 10px 13px;
  border: 1px solid var(--border);
  border-radius: var(--r-sm);
  background: var(--inset);
  font-size: 0.9rem;
}

.algorithm-step strong,
.solution-step strong {
  color: var(--accent-ink);
}

.solution-step {
  margin-bottom: 6px;
  padding-left: 12px;
  border-left: 2px solid var(--accent-line);
  font-size: 0.9rem;
}

.example-label {
  display: inline-flex;
  align-items: center;
  padding: 3px 10px;
  margin-bottom: 10px;
  border: 1px solid var(--violet-line);
  border-radius: 999px;
  background: var(--violet-soft);
  color: var(--violet-ink);
  font-size: 0.66rem;
  font-weight: 700;
  letter-spacing: 0.1em;
  text-transform: uppercase;
}

.example-label.example-generated {
  border-color: var(--accent-line);
  background: var(--accent-soft);
  color: var(--accent-ink);
}

.badge {
  display: inline-flex;
  align-items: center;
  padding: 3px 10px;
  border: 1px solid var(--yellow-line);
  border-radius: 999px;
  background: var(--yellow-soft);
  color: var(--yellow-ink);
  font-size: 0.64rem;
  font-weight: 700;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  vertical-align: middle;
}

/* ------------------------------------------------------- cards & grids -- */

.card,
.mini-card,
.comparison-card,
.comparison-item,
.rotation-card,
.complexity-card,
.pros,
.cons,
.complexity-box {
  padding: clamp(16px, 2.2vw, 22px);
  border: 1px solid var(--border);
  border-radius: var(--r-lg);
  background: var(--surface);
  box-shadow: var(--shadow-sm);
  transition:
    border-color var(--dur) var(--ease),
    box-shadow var(--dur) var(--ease),
    transform var(--dur) var(--ease);
}

.card {
  margin-bottom: 18px;
}

.card:hover,
.mini-card:hover,
.comparison-card:hover,
.rotation-card:hover,
.complexity-card:hover {
  border-color: var(--border2);
  box-shadow: var(--shadow);
  transform: translateY(-2px);
}

.mini-grid,
.rotation-types,
.comparison,
.comparison-table,
.pros-cons,
.complexity {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
  gap: 14px;
  margin: 16px 0;
}

.comparison > div,
.comparison .left,
.comparison .right {
  min-width: 0;
}

.pros,
.comparison-item.good,
.array-card {
  border-color: var(--green-line);
  background: var(--green-soft);
}

.cons,
.comparison-item.bad,
.list-card {
  border-color: var(--red-line);
  background: var(--red-soft);
}

.pros h4 {
  color: var(--green-ink);
}

.cons h4 {
  color: var(--red-ink);
}

.comparison-item.good h4 {
  color: var(--green-ink);
}

.comparison-item.bad h4 {
  color: var(--red-ink);
}

.complexity-card {
  text-align: center;
}

.complexity-card .value,
.complexity-card h4 + .value {
  margin: 4px 0 6px;
  color: var(--accent-ink);
  font-family: var(--mono);
  font-size: 1.3rem;
  font-weight: 700;
}

.complexity-card p {
  color: var(--muted);
  font-size: 0.82rem;
}

/* --------------------------------------------------- complexity badges -- */

.complexity,
.complexity-badge,
.complexity-good,
.complexity-bad,
.o-1,
.o-n,
.o-n2 {
  font-family: var(--mono);
}

.complexity-badge,
.complexity-good,
.complexity-bad,
.o-1,
.o-n,
.o-n2 {
  display: inline-block;
  padding: 2px 9px;
  border: 1px solid var(--border2);
  border-radius: 999px;
  background: var(--surface2);
  font-size: 0.78rem;
  font-weight: 700;
  white-space: nowrap;
}

.complexity-good,
.o-1,
.complexity.fast,
.complexity.good {
  border-color: var(--green-line);
  background: var(--green-soft);
  color: var(--green-ink);
}

.o-n,
.complexity.medium,
.complexity.average {
  border-color: var(--yellow-line);
  background: var(--yellow-soft);
  color: var(--yellow-ink);
}

.complexity-bad,
.o-n2,
.complexity.slow,
.complexity.bad {
  border-color: var(--red-line);
  background: var(--red-soft);
  color: var(--red-ink);
}

/* `.complexity` doubles as a grid wrapper on some pages and an inline badge
   on others -- only give it badge chrome when it carries a state class. */
.complexity.fast,
.complexity.good,
.complexity.medium,
.complexity.average,
.complexity.slow,
.complexity.bad {
  display: inline-block;
  padding: 2px 9px;
  border-width: 1px;
  border-style: solid;
  border-radius: 999px;
  font-size: 0.78rem;
  font-weight: 700;
  white-space: nowrap;
}

/* ----------------------------------------------------------------code --- */

code {
  padding: 0.15em 0.4em;
  border: 1px solid var(--border);
  border-radius: 5px;
  background: var(--code-bg);
  color: var(--code-color);
  font-family: var(--mono);
  font-size: 0.86em;
}

pre {
  margin: 14px 0;
  padding: 16px 18px;
  border: 1px solid var(--border);
  border-radius: var(--r-md);
  background: var(--code-bg);
  color: var(--code-color);
  font-family: var(--mono);
  font-size: 0.83rem;
  line-height: 1.6;
  overflow-x: auto;
}

pre code {
  padding: 0;
  border: 0;
  background: none;
  font-size: inherit;
}

.code-block {
  margin: 14px 0;
  padding: 16px 18px;
  border: 1px solid var(--border);
  border-radius: var(--r-md);
  background: var(--code-bg);
  color: var(--code-color);
  font-family: var(--mono);
  font-size: 0.83rem;
  line-height: 1.65;
  white-space: pre-wrap;
  overflow-x: auto;
}

.code-block .keyword,
.keyword {
  color: var(--code-keyword);
  font-weight: 600;
}

.code-block .string,
.string {
  color: var(--code-string);
}

.code-block .comment,
.comment {
  color: var(--code-comment);
  font-style: italic;
}

.code-block .type,
.type {
  color: var(--code-type);
}

.code-block .function,
.function {
  color: var(--code-function);
}

/* ------------------------------------------------------------- tables --- */

.table-container,
.complexity-chart,
.comparison-table.has-table {
  margin: 16px 0;
  overflow-x: auto;
}

table {
  width: 100%;
  margin: 16px 0;
  border-collapse: separate;
  border-spacing: 0;
  border: 1px solid var(--border);
  border-radius: var(--r-md);
  overflow: hidden;
  font-size: 0.89rem;
}

th,
td {
  padding: 10px 13px;
  border-bottom: 1px solid var(--border);
  text-align: left;
  vertical-align: top;
}

th {
  background: var(--surface3);
  color: var(--text);
  font-size: 0.72rem;
  font-weight: 700;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  white-space: nowrap;
}

td {
  color: var(--text2);
}

tr:last-child td {
  border-bottom: 0;
}

tbody tr:nth-child(even) td,
table tr:nth-child(even) td {
  background: var(--inset);
}

tr:hover td {
  background: var(--accent-soft);
}

/* ------------------------------------------------ data-structure visuals - */

.visual,
.visual-example,
.visual-diagram,
.visualization,
.diagram,
.tree-diagram,
.tree-visual,
.array-visual,
.stack-visual,
.queue-visual,
.complexity-box {
  margin: 16px 0;
}

.visual,
.visual-example,
.visual-diagram,
.visualization,
.diagram,
.tree-diagram,
.tree-visual {
  padding: 18px;
  border: 1px solid var(--border);
  border-radius: var(--r-md);
  background: var(--inset);
  text-align: center;
}

.tree-diagram,
.tree-visual,
.diagram {
  font-family: var(--mono);
  font-size: 0.84rem;
  line-height: 1.75;
  color: var(--text);
  overflow-x: auto;
}

.diagram,
body[data-cs210-page="bst"] .tree-diagram {
  white-space: pre;
  text-align: left;
}

.visual-title {
  margin-bottom: 10px;
  color: var(--muted);
  font-size: 0.7rem;
  font-weight: 700;
  letter-spacing: 0.12em;
  text-transform: uppercase;
}

.array-visual,
.stack-visual,
.queue-visual {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: center;
  gap: 8px;
  padding: 18px;
  border: 1px solid var(--border);
  border-radius: var(--r-md);
  background: var(--inset);
}

.array-cell,
.array-box,
.array-item,
.stack-item,
.queue-item {
  display: inline-grid;
  margin: 3px 2px;
  place-items: center;
  min-width: 46px;
  min-height: 42px;
  padding: 8px 12px;
  border: 1px solid var(--accent-line);
  border-radius: var(--r-sm);
  background: var(--surface);
  color: var(--text);
  font-family: var(--mono);
  font-size: 0.88rem;
  font-weight: 600;
  box-shadow: var(--shadow-sm);
  transition:
    transform 160ms var(--ease),
    border-color 160ms var(--ease);
}

.array-cell:hover,
.stack-item:hover,
.queue-item:hover {
  transform: translateY(-2px);
  border-color: var(--accent);
}

.array-index,
.array-cell .index {
  margin-top: 4px;
  color: var(--muted);
  font-family: var(--mono);
  font-size: 0.7rem;
  text-align: center;
}

.arrow {
  color: var(--muted);
  font-family: var(--mono);
  font-size: 1rem;
}

.pivot {
  border-color: var(--yellow-line);
  background: var(--yellow-soft);
  color: var(--yellow-ink);
}

.sorted,
.greater-than {
  border-color: var(--green-line);
  background: var(--green-soft);
  color: var(--green-ink);
}

.unsorted,
.less-than {
  border-color: var(--border2);
  background: var(--surface2);
  color: var(--text2);
}

.merging {
  border-color: var(--accent-line);
  background: var(--accent-soft);
  color: var(--accent-ink);
}

ul.styled-list {
  list-style: none;
  padding-left: 0;
}

ul.styled-list li {
  position: relative;
  padding-left: 20px;
}

ul.styled-list li::before {
  content: "";
  position: absolute;
  left: 4px;
  top: 0.65em;
  width: 6px;
  height: 6px;
  border-radius: 50%;
  background: var(--accent);
}

/* ==========================================================================
   Exam question banks (midterm-1, quiz-1, quiz-2)
   ========================================================================== */

body[data-cs210="exam"] .container {
  max-width: 900px;
  padding-top: 8px;
}

.header-tag {
  display: inline-flex;
  align-items: center;
  padding: 4px 12px;
  border: 1px solid var(--accent-line);
  border-radius: 999px;
  background: var(--accent-soft);
  color: var(--accent-ink);
  font-family: var(--mono);
  font-size: 0.68rem;
  font-weight: 700;
  letter-spacing: 0.16em;
  text-transform: uppercase;
}

/* ---------------------------------------------------------- progress --- */

.progress-wrap {
  position: sticky;
  top: 0;
  z-index: 50;
  display: flex;
  align-items: center;
  gap: 14px;
  padding: 11px clamp(14px, 4vw, 28px);
  border-bottom: 1px solid var(--border);
  background: var(--progress-bg);
  backdrop-filter: blur(12px) saturate(1.3);
  -webkit-backdrop-filter: blur(12px) saturate(1.3);
}

.progress-bar-outer {
  flex: 1;
  height: 5px;
  border-radius: 999px;
  background: var(--surface3);
  overflow: hidden;
}

.progress-bar-inner {
  width: 0;
  height: 100%;
  border-radius: inherit;
  background: linear-gradient(90deg, var(--accent), var(--accent2));
  transition: width 480ms var(--ease);
}

.progress-label {
  flex: 0 0 auto;
  color: var(--muted);
  font-family: var(--mono);
  font-size: 0.72rem;
  font-weight: 600;
  letter-spacing: 0.05em;
  white-space: nowrap;
}

/* ---------------------------------------------------- section headers --- */

.section-header {
  display: flex;
  align-items: center;
  gap: 12px;
  margin: 30px 0 16px;
}

.section-line {
  flex: 1;
  height: 1px;
  background: var(--border);
}

.section-title {
  color: var(--muted);
  font-family: var(--mono);
  font-size: 0.7rem;
  font-weight: 600;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  white-space: nowrap;
}

.section-badge {
  display: inline-flex;
  align-items: center;
  padding: 4px 12px;
  border: 1px solid var(--accent-line);
  border-radius: 999px;
  background: var(--accent-soft);
  color: var(--accent-ink);
  font-family: var(--mono);
  font-size: 0.68rem;
  font-weight: 700;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  white-space: nowrap;
}

.badge-written,
.badge-rec {
  border-color: var(--violet-line);
  background: var(--violet-soft);
  color: var(--violet-ink);
}

.badge-bigo,
.badge-bigoh,
.badge-sort {
  border-color: var(--yellow-line);
  background: var(--yellow-soft);
  color: var(--yellow-ink);
}

.badge-ll {
  border-color: var(--green-line);
  background: var(--green-soft);
  color: var(--green-ink);
}

/* ------------------------------------------------------ question card --- */

.question-card {
  position: relative;
  margin-bottom: 14px;
  padding: clamp(17px, 2.3vw, 24px);
  border: 1px solid var(--border);
  border-radius: var(--r-lg);
  background: var(--surface);
  box-shadow: var(--shadow-sm);
  transition:
    border-color var(--dur) var(--ease),
    box-shadow var(--dur) var(--ease),
    transform var(--dur) var(--ease);
  animation: cs-rise 520ms var(--ease) both;
}

.question-card:hover {
  border-color: var(--border2);
  box-shadow: var(--shadow);
  transform: translateY(-2px);
}

.question-card.correct {
  border-color: var(--green-line);
}

.question-card.incorrect {
  border-color: var(--red-line);
}

.question-card.partial {
  border-color: var(--yellow-line);
}

.card-head {
  display: flex;
  align-items: flex-start;
  gap: 12px;
  margin-bottom: 14px;
}

.card-head > div:first-child {
  flex: 0 0 auto;
}

.q-num {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-width: 38px;
  padding: 4px 10px;
  border: 1px solid var(--accent-line);
  border-radius: 999px;
  background: var(--accent-soft);
  color: var(--accent-ink);
  font-family: var(--mono);
  font-size: 0.72rem;
  font-weight: 700;
}

.q-text {
  flex: 1;
  min-width: 0;
  color: var(--text);
  font-size: 1rem;
  font-weight: 500;
  line-height: 1.55;
}

.q-pts,
.q-era,
.q-source,
.diagram-note {
  flex: 0 0 auto;
  color: var(--muted);
  font-family: var(--mono);
  font-size: 0.7rem;
  font-weight: 600;
  letter-spacing: 0.05em;
  white-space: nowrap;
}

.q-era,
.q-source {
  display: block;
  margin-top: 4px;
  white-space: normal;
}

.diagram-note {
  display: block;
  margin: -6px 0 12px;
  white-space: normal;
}

/* ------------------------------------------------------------ options --- */

.options-list {
  display: flex;
  flex-direction: column;
  gap: 8px;
}

.option-label {
  display: flex;
  align-items: center;
  gap: 11px;
  padding: 11px 14px;
  border: 1px solid var(--border);
  border-radius: var(--r-md);
  background: var(--inset);
  color: var(--text);
  font-size: 0.94rem;
  line-height: 1.5;
  cursor: pointer;
  transition:
    border-color 160ms var(--ease),
    background-color 160ms var(--ease),
    transform 160ms var(--ease);
}

.option-label:hover {
  border-color: var(--accent-line);
  background: var(--accent-soft);
  transform: translateX(2px);
}

.option-label input[type="radio"] {
  position: absolute;
  width: 1px;
  height: 1px;
  opacity: 0;
  pointer-events: none;
}

.option-circle {
  display: grid;
  place-items: center;
  flex: 0 0 auto;
  width: 26px;
  height: 26px;
  border: 1px solid var(--border2);
  border-radius: 8px;
  background: var(--surface);
  color: var(--text2);
  font-family: var(--mono);
  font-size: 0.75rem;
  font-weight: 700;
  transition:
    background-color 160ms var(--ease),
    border-color 160ms var(--ease),
    color 160ms var(--ease);
}

.option-label.selected {
  border-color: var(--accent);
  background: var(--accent-soft);
}

.option-label.selected .option-circle {
  border-color: transparent;
  background: var(--accent);
  color: var(--on-accent);
}

.option-label.show-correct {
  border-color: var(--green-line);
  background: var(--green-soft);
  color: var(--green-ink);
}

.option-label.show-correct .option-circle {
  border-color: transparent;
  background: var(--green);
  color: var(--on-accent);
}

.option-label.show-wrong {
  border-color: var(--red-line);
  background: var(--red-soft);
  color: var(--red-ink);
}

.option-label.show-wrong .option-circle {
  border-color: transparent;
  background: var(--red);
  color: var(--on-accent);
}

/* ------------------------------------------------------ written input --- */

.textarea-wrap {
  margin-top: 4px;
}

textarea.written-answer {
  width: 100%;
  min-height: 118px;
  padding: 12px 14px;
  border: 1px solid var(--border2);
  border-radius: var(--r-md);
  background: var(--inset);
  color: var(--text);
  font-family: var(--mono);
  font-size: 0.86rem;
  line-height: 1.6;
  resize: vertical;
  transition:
    border-color 160ms var(--ease),
    box-shadow 160ms var(--ease);
}

textarea.written-answer:focus {
  outline: none;
  border-color: var(--accent);
  box-shadow: 0 0 0 3px var(--accent-soft);
}

pre.code-snippet {
  margin: 0 0 14px;
  padding: 15px 17px;
  border: 1px solid var(--border);
  border-radius: var(--r-md);
  background: var(--code-bg);
  color: var(--code-color);
  font-family: var(--mono);
  font-size: 0.82rem;
  line-height: 1.6;
  overflow-x: auto;
}

/* -------------------------------------------------------- big-O table --- */

.bigo-table {
  width: 100%;
  margin: 4px 0 0;
}

.bigo-table th {
  white-space: normal;
}

.bigo-input {
  width: 100%;
  padding: 8px 11px;
  border: 1px solid var(--border2);
  border-radius: var(--r-sm);
  background: var(--inset);
  color: var(--text);
  font-family: var(--mono);
  font-size: 0.85rem;
  transition:
    border-color 160ms var(--ease),
    box-shadow 160ms var(--ease);
}

.bigo-input:focus {
  outline: none;
  border-color: var(--accent);
  box-shadow: 0 0 0 3px var(--accent-soft);
}

.bigo-input.correct-input {
  border-color: var(--green);
  background: var(--green-soft);
  color: var(--green-ink);
}

.bigo-input.wrong-input {
  border-color: var(--red);
  background: var(--red-soft);
  color: var(--red-ink);
}

/* ----------------------------------------------------------- feedback --- */

.feedback-box {
  display: none;
  margin-top: 14px;
  padding: 14px 16px;
  border: 1px solid var(--border);
  border-left: 3px solid var(--accent);
  border-radius: var(--r-md);
  background: var(--surface2);
  color: var(--text2);
  font-size: 0.9rem;
}

.feedback-box.show {
  display: block;
  animation: cs-reveal 340ms var(--ease) both;
}

.feedback-box.correct-fb {
  border-left-color: var(--green);
  background: var(--green-soft);
}

.feedback-box.incorrect-fb {
  border-left-color: var(--red);
  background: var(--red-soft);
}

.feedback-box.partial-fb {
  border-left-color: var(--yellow);
  background: var(--yellow-soft);
}

.fb-icon {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  margin-bottom: 6px;
  font-size: 0.8rem;
  font-weight: 700;
  letter-spacing: 0.06em;
  text-transform: uppercase;
}

.fb-icon.ok {
  color: var(--green-ink);
}

.fb-icon.no {
  color: var(--red-ink);
}

.fb-icon.so {
  color: var(--yellow-ink);
}

.fb-explanation {
  color: var(--text2);
  font-size: 0.9rem;
  line-height: 1.6;
}

.fb-keywords {
  display: flex;
  flex-wrap: wrap;
  gap: 6px;
  margin-top: 10px;
}

.kw-tag {
  display: inline-flex;
  align-items: center;
  padding: 3px 9px;
  border: 1px solid var(--border2);
  border-radius: 999px;
  background: var(--surface);
  color: var(--muted);
  font-family: var(--mono);
  font-size: 0.7rem;
  font-weight: 600;
}

.kw-tag.found {
  border-color: var(--green-line);
  background: var(--green-soft);
  color: var(--green-ink);
}

/* ------------------------------------------------------------ actions --- */

.actions {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
  margin: 26px 0 0;
}

.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  flex: 1 1 auto;
  min-width: 160px;
  padding: 13px 24px;
  border: 1px solid transparent;
  border-radius: var(--r-md);
  font-family: inherit;
  font-size: 0.95rem;
  font-weight: 650;
  line-height: 1.2;
  cursor: pointer;
  transition:
    transform 160ms var(--ease),
    box-shadow 160ms var(--ease),
    background-color 160ms var(--ease),
    border-color 160ms var(--ease),
    filter 160ms var(--ease);
}

.btn-primary {
  background: linear-gradient(135deg, var(--accent), var(--accent2));
  color: var(--on-accent);
  box-shadow: var(--shadow-accent);
}

.btn-primary:hover {
  transform: translateY(-2px);
  filter: saturate(1.06);
}

.btn-outline {
  border-color: var(--border2);
  background: var(--surface);
  color: var(--text);
  box-shadow: var(--shadow-sm);
}

.btn-outline:hover {
  transform: translateY(-2px);
  border-color: var(--accent-line);
  background: var(--accent-soft);
}

.btn:active {
  transform: translateY(0);
}

/* ------------------------------------------------------------- result --- */

.result-section {
  display: none;
  margin-top: 24px;
  padding: clamp(24px, 4vw, 38px);
  border: 1px solid var(--accent-line);
  border-radius: var(--r-xl);
  background:
    linear-gradient(150deg, var(--accent-soft), transparent 60%), var(--surface);
  box-shadow: var(--shadow-lg);
  text-align: center;
}

.result-section.show {
  display: block;
  animation: cs-pop 420ms var(--ease) both;
}

.score-big {
  margin: 6px 0 4px;
  background: linear-gradient(135deg, var(--accent), var(--accent2));
  -webkit-background-clip: text;
  background-clip: text;
  color: transparent;
  font-size: clamp(2.4rem, 1.6rem + 3.4vw, 3.4rem);
  font-weight: 750;
  letter-spacing: -0.03em;
  line-height: 1.05;
}

.score-label {
  color: var(--text2);
  font-family: var(--mono);
  font-size: 0.85rem;
}

.score-breakdown {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 10px;
  max-width: 420px;
  margin: 22px auto 0;
}

.sb-item {
  padding: 13px 10px;
  border: 1px solid var(--border);
  border-radius: var(--r-md);
  background: var(--surface2);
}

.sb-item .sb-val {
  font-family: var(--mono);
  font-size: 1.5rem;
  font-weight: 700;
  line-height: 1.1;
}

.sb-item .sb-label {
  margin-top: 2px;
  color: var(--muted);
  font-size: 0.68rem;
  font-weight: 700;
  letter-spacing: 0.1em;
  text-transform: uppercase;
}

.sb-correct {
  border-color: var(--green-line);
  background: var(--green-soft);
}

.sb-wrong {
  border-color: var(--red-line);
  background: var(--red-soft);
}

.sb-partial {
  border-color: var(--yellow-line);
  background: var(--yellow-soft);
}

.sb-correct .sb-val {
  color: var(--green-ink);
}

.sb-wrong .sb-val {
  color: var(--red-ink);
}

.sb-partial .sb-val {
  color: var(--yellow-ink);
}

header .sg-page-search.sg-page-search {
  display: inline-flex;
  width: auto;
  padding: 4px 5px;
  border-radius: 999px;
  border-width: 1px;
  border-style: solid;
}

header .sg-page-search.sg-page-search .sg-page-search__input {
  border-radius: 999px;
}

/* --------------------------------------------------------- theme toggle -- */
/* html-theme-sync.js injects its own .sg-theme-toggle rules at runtime, after
   this file. The doubled class outranks them without reaching for !important. */

.sg-theme-toggle.sg-theme-toggle {
  position: fixed;
  inset: 14px 14px auto auto;
  z-index: 99999;
  display: inline-flex;
  align-items: center;
  gap: 8px;
  width: auto;
  height: 36px;
  padding: 0 14px 0 11px;
  border: 1px solid var(--border2);
  border-radius: 999px;
  background: color-mix(in srgb, var(--surface) 82%, transparent);
  color: var(--text2);
  font-family: var(--sans);
  font-size: 0.78rem;
  font-weight: 650;
  letter-spacing: 0.02em;
  cursor: pointer;
  box-shadow: var(--shadow);
  backdrop-filter: blur(12px) saturate(1.4);
  -webkit-backdrop-filter: blur(12px) saturate(1.4);
  transition:
    transform 200ms var(--ease),
    border-color 200ms var(--ease),
    color 200ms var(--ease),
    background-color 200ms var(--ease);
}

.sg-theme-toggle.sg-theme-toggle:hover,
.sg-theme-toggle.sg-theme-toggle:focus-visible {
  transform: translateY(-1px);
  border-color: var(--accent-line);
  color: var(--text);
}

.sg-theme-toggle svg {
  display: block;
  width: 15px;
  height: 15px;
  transition: transform 320ms var(--ease);
}

.sg-theme-toggle .sg-icon-sun {
  display: none;
}

html[data-theme="dark"] .sg-theme-toggle .sg-icon-sun {
  display: block;
}

html[data-theme="dark"] .sg-theme-toggle .sg-icon-moon {
  display: none;
}

.sg-theme-toggle:hover svg {
  transform: rotate(-18deg);
}

[dir="rtl"] .sg-theme-toggle.sg-theme-toggle,
html[lang="ar"] .sg-theme-toggle.sg-theme-toggle {
  inset: 14px auto auto 14px;
}

/* The exam pages put a sticky progress bar at the top; nudge the toggle down
   so the two never overlap. */
body[data-cs210="exam"] .sg-theme-toggle.sg-theme-toggle {
  inset: auto 14px 14px auto;
}

/* ----------------------------------------------------------- animation -- */

@keyframes cs-rise {
  from {
    opacity: 0;
    transform: translateY(12px);
  }

  to {
    opacity: 1;
    transform: translateY(0);
  }
}

@keyframes cs-fade {
  from {
    opacity: 0;
    transform: translateY(6px);
  }

  to {
    opacity: 1;
    transform: translateY(0);
  }
}

@keyframes cs-reveal {
  from {
    opacity: 0;
    transform: translateY(-5px);
  }

  to {
    opacity: 1;
    transform: translateY(0);
  }
}

@keyframes cs-pop {
  from {
    opacity: 0;
    transform: scale(0.96);
  }

  to {
    opacity: 1;
    transform: scale(1);
  }
}

@media (prefers-reduced-motion: reduce) {
  html {
    scroll-behavior: auto;
  }

  *,
  *::before,
  *::after {
    animation-duration: 0.001ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.001ms !important;
  }
}

/* --------------------------------------------------------------- small -- */

@media (max-width: 768px) {
  body {
    font-size: 14.5px;
  }

  .nav ul,
  nav ul,
  .toc ul,
  .menu {
    grid-template-columns: 1fr;
  }

  .score-breakdown {
    grid-template-columns: 1fr;
  }

  body[data-cs210-page="cheat-sheet-2"] {
    grid-template-columns: minmax(0, 1fr);
  }

  body[data-cs210-page="cheat-sheet-2"] .sidebar {
    position: static;
    max-height: none;
  }
}

@media (max-width: 600px) {
  .card-head {
    flex-wrap: wrap;
  }

  .btn {
    min-width: 100%;
  }

  .sg-theme-toggle.sg-theme-toggle {
    inset: 10px 10px auto auto;
  }

  body[data-cs210="exam"] .sg-theme-toggle.sg-theme-toggle {
    inset: auto 10px 10px auto;
  }
}

@media print {
  body {
    background: #fff;
    color: #000;
  }

  .sg-theme-toggle,
  .progress-wrap,
  .actions,
  #scrollTop {
    display: none;
  }

  section,
  .section,
  .card,
  .question-card {
    break-inside: avoid;
    box-shadow: none;
  }
}