/* ========== CAAL Finals Guide — shared styles ========== */
:root {
  --bg: #0d1117;
  --bg-2: #161b22;
  --bg-3: #1c232c;
  --border: #2d333b;
  --text: #e6edf3;
  --text-dim: #9ba9b7;
  --accent: #58a6ff;
  --accent-2: #f78166;
  --green: #56d364;
  --yellow: #e3b341;
  --red: #ff6b6b;
  --purple: #bc8cff;
  --pink: #ff7eb6;
  --cyan: #76e4f7;
  --code-bg: #0a0e13;
}

* { box-sizing: border-box; }

html { scroll-behavior: smooth; }

body {
  margin: 0;
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Helvetica, Arial, sans-serif;
  background: var(--bg);
  color: var(--text);
  line-height: 1.55;
  font-size: 15px;
}

/* ===== Top nav ===== */
.topnav {
  position: sticky;
  top: 0;
  z-index: 100;
  background: rgba(13, 17, 23, 0.92);
  backdrop-filter: blur(10px);
  border-bottom: 1px solid var(--border);
  padding: 10px 24px;
  display: flex;
  flex-wrap: wrap;
  gap: 4px 18px;
  align-items: center;
  font-size: 14px;
}
.topnav .brand {
  font-weight: 700;
  color: var(--accent);
  margin-right: 12px;
  font-size: 15px;
}
.topnav a {
  color: var(--text-dim);
  text-decoration: none;
  padding: 4px 10px;
  border-radius: 6px;
  transition: all 0.15s;
}
.topnav a:hover { background: var(--bg-2); color: var(--text); }
.topnav a.active { background: var(--bg-2); color: var(--accent); }

/* ===== Main container ===== */
main {
  max-width: 1180px;
  margin: 0 auto;
  padding: 28px 24px 80px;
}

/* ===== Hero/title ===== */
.hero {
  border: 1px solid var(--border);
  border-radius: 12px;
  padding: 28px 32px;
  background: linear-gradient(135deg, rgba(88,166,255,0.08), rgba(188,140,255,0.05));
  margin-bottom: 28px;
}
.hero h1 {
  margin: 0 0 8px;
  font-size: 28px;
  letter-spacing: -0.3px;
}
.hero .sub { color: var(--text-dim); font-size: 15px; }

/* ===== Sections ===== */
h2 {
  margin: 36px 0 14px;
  padding-bottom: 8px;
  border-bottom: 1px solid var(--border);
  font-size: 22px;
}
h3 { margin: 22px 0 10px; font-size: 17px; color: var(--accent); }
h4 { margin: 16px 0 6px; font-size: 15px; color: var(--text-dim); text-transform: uppercase; letter-spacing: 0.4px; }

p { margin: 8px 0; }

/* ===== Cards ===== */
.card {
  background: var(--bg-2);
  border: 1px solid var(--border);
  border-radius: 10px;
  padding: 16px 18px;
  margin: 14px 0;
}
.card.compact { padding: 12px 14px; }

.grid {
  display: grid;
  gap: 14px;
  grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
}
.grid-2 {
  display: grid;
  gap: 14px;
  grid-template-columns: 1fr 1fr;
}
@media (max-width: 720px) { .grid-2 { grid-template-columns: 1fr; } }

/* ===== Callouts ===== */
.callout {
  border-left: 4px solid var(--accent);
  background: rgba(88,166,255,0.06);
  padding: 10px 14px;
  border-radius: 0 8px 8px 0;
  margin: 12px 0;
}
.callout.analogy { border-color: var(--green); background: rgba(86,211,100,0.07); }
.callout.warn { border-color: var(--yellow); background: rgba(227,179,65,0.07); }
.callout.formula { border-color: var(--purple); background: rgba(188,140,255,0.07); font-family: "Cascadia Code", "Consolas", monospace; }
.callout.source { border-color: var(--text-dim); background: rgba(155,169,183,0.05); font-size: 13px; color: var(--text-dim); }
.callout .tag {
  display: inline-block;
  font-size: 11px;
  text-transform: uppercase;
  letter-spacing: 0.6px;
  font-weight: 700;
  margin-right: 8px;
  padding: 2px 6px;
  border-radius: 4px;
  background: rgba(255,255,255,0.06);
}
.callout.analogy .tag { color: var(--green); }
.callout.warn .tag { color: var(--yellow); }
.callout.formula .tag { color: var(--purple); font-family: inherit; }
.callout.source .tag { color: var(--text-dim); }

/* ===== Tables ===== */
table {
  width: 100%;
  border-collapse: collapse;
  margin: 12px 0;
  font-size: 14px;
}
th, td {
  padding: 8px 12px;
  text-align: left;
  border-bottom: 1px solid var(--border);
}
th { background: var(--bg-3); color: var(--accent); font-weight: 600; }
tr:hover td { background: rgba(255,255,255,0.02); }
td code { background: var(--code-bg); padding: 1px 5px; border-radius: 3px; }

/* ===== Code blocks ===== */
code {
  font-family: "Cascadia Code", "JetBrains Mono", "Consolas", monospace;
  font-size: 13px;
}
pre {
  background: var(--code-bg);
  border: 1px solid var(--border);
  border-radius: 8px;
  padding: 12px 14px;
  overflow-x: auto;
  font-size: 13px;
  line-height: 1.5;
}
pre code { background: transparent; padding: 0; }

.kbd {
  display: inline-block;
  background: var(--bg-3);
  border: 1px solid var(--border);
  border-radius: 4px;
  padding: 1px 6px;
  font-family: "Cascadia Code", monospace;
  font-size: 12.5px;
  color: var(--cyan);
}

/* ===== Pipeline diagram ===== */
.pipeline {
  display: grid;
  grid-template-columns: 80px repeat(11, minmax(40px, 1fr));
  gap: 3px;
  margin: 14px 0;
  font-size: 12px;
  font-family: "Cascadia Code", monospace;
  overflow-x: auto;
}
.pipeline .label { padding: 6px 8px; color: var(--text-dim); text-align: right; }
.pipeline .cyc { padding: 6px 4px; text-align: center; color: var(--text-dim); border-bottom: 1px solid var(--border); }
.pipeline .stage { padding: 6px 4px; text-align: center; border-radius: 4px; font-weight: 600; }
.pipeline .if   { background: rgba(86,211,100,0.20); color: #9be9a8; }
.pipeline .id   { background: rgba(88,166,255,0.20); color: #8ec3ff; }
.pipeline .ex   { background: rgba(227,179,65,0.20); color: #f0c75e; }
.pipeline .me   { background: rgba(247,129,102,0.20); color: #ffa78a; }
.pipeline .wb   { background: rgba(188,140,255,0.20); color: #d5b0ff; }
.pipeline .is   { background: rgba(118,228,247,0.18); color: #76e4f7; }
.pipeline .raw  { background: rgba(255,107,107,0.20); color: #ff9999; }
.pipeline .stall{ background: rgba(255,107,107,0.10); color: #ff9999; font-style: italic; }
.pipeline .empty{ }

/* ===== FSM (branch predictor) ===== */
.fsm-grid {
  display: flex;
  gap: 14px;
  justify-content: center;
  flex-wrap: wrap;
  margin: 12px 0;
}
.fsm-state {
  border: 2px solid var(--border);
  border-radius: 50%;
  width: 110px;
  height: 110px;
  display: flex;
  align-items: center;
  justify-content: center;
  text-align: center;
  font-size: 12px;
  font-weight: 600;
  padding: 6px;
}
.fsm-state.taken { border-color: var(--green); background: rgba(86,211,100,0.10); }
.fsm-state.not-taken { border-color: var(--red); background: rgba(255,107,107,0.10); }

/* ===== Bit-field diagram ===== */
.bitfield {
  display: flex;
  margin: 12px 0;
  border: 1px solid var(--border);
  border-radius: 6px;
  overflow: hidden;
  font-family: "Cascadia Code", monospace;
  font-size: 12.5px;
}
.bitfield .field {
  flex: 1;
  padding: 8px 6px;
  text-align: center;
  border-right: 1px solid var(--border);
}
.bitfield .field:last-child { border-right: none; }
.bitfield .field .name { font-weight: 700; color: var(--accent); }
.bitfield .field .bits { color: var(--text-dim); font-size: 11px; margin-top: 4px; }
.bitfield .field.tag-f { background: rgba(188,140,255,0.10); }
.bitfield .field.idx-f { background: rgba(88,166,255,0.10); }
.bitfield .field.off-f { background: rgba(247,129,102,0.10); }
.bitfield .field.vpn-f { background: rgba(86,211,100,0.10); }
.bitfield .field.ppn-f { background: rgba(118,228,247,0.10); }

/* ===== Memory hierarchy diagram ===== */
.memhier {
  display: flex;
  flex-direction: column;
  align-items: center;
  margin: 14px 0;
  gap: 4px;
}
.memhier .level {
  border: 1px solid var(--border);
  border-radius: 6px;
  padding: 8px 14px;
  text-align: center;
  font-size: 13px;
  background: var(--bg-3);
}
.memhier .level .meta { color: var(--text-dim); font-size: 11px; margin-top: 2px; }
.memhier .l1 { width: 30%; background: rgba(86,211,100,0.12); border-color: var(--green); }
.memhier .l2 { width: 50%; background: rgba(88,166,255,0.10); border-color: var(--accent); }
.memhier .l3 { width: 70%; background: rgba(227,179,65,0.10); border-color: var(--yellow); }
.memhier .l4 { width: 88%; background: rgba(247,129,102,0.10); border-color: var(--accent-2); }
.memhier .l5 { width: 100%; background: rgba(188,140,255,0.10); border-color: var(--purple); }

/* ===== Misc ===== */
.tags { display: flex; flex-wrap: wrap; gap: 6px; margin: 8px 0; }
.tag-chip {
  font-size: 11px;
  padding: 3px 8px;
  border-radius: 10px;
  background: var(--bg-3);
  border: 1px solid var(--border);
  color: var(--text-dim);
}

.toc {
  background: var(--bg-2);
  border: 1px solid var(--border);
  border-radius: 8px;
  padding: 12px 18px;
  margin: 14px 0 22px;
  font-size: 14px;
}
.toc ul { margin: 4px 0; padding-left: 22px; }
.toc a { color: var(--accent); text-decoration: none; }
.toc a:hover { text-decoration: underline; }

.highlight { color: var(--yellow); font-weight: 600; }
.muted { color: var(--text-dim); }
.mono { font-family: "Cascadia Code", monospace; }

.q-correct { color: var(--green); font-weight: 700; }
.q-wrong { color: var(--red); text-decoration: line-through; opacity: 0.55; }

hr {
  border: none;
  border-top: 1px dashed var(--border);
  margin: 28px 0;
}

/* Inline math-ish style */
.eq {
  font-family: "Cascadia Code", monospace;
  background: var(--code-bg);
  padding: 2px 7px;
  border-radius: 4px;
  color: var(--cyan);
}

footer {
  text-align: center;
  color: var(--text-dim);
  font-size: 13px;
  margin-top: 50px;
  padding-top: 18px;
  border-top: 1px solid var(--border);
}

/* ===== Quiz ===== */
.quiz-block {
  background: var(--bg-2);
  border: 1px solid var(--border);
  border-radius: 10px;
  padding: 18px 20px;
  margin: 14px 0;
}
.quiz-q {
  font-weight: 600;
  margin-bottom: 10px;
  font-size: 15px;
}
.quiz-q .q-num {
  display: inline-block;
  background: var(--accent);
  color: var(--bg);
  border-radius: 4px;
  padding: 1px 8px;
  font-size: 13px;
  margin-right: 8px;
}
.quiz-opt {
  display: block;
  background: var(--bg-3);
  border: 1px solid var(--border);
  border-radius: 6px;
  padding: 10px 14px;
  margin: 6px 0;
  cursor: pointer;
  user-select: none;
  transition: all 0.12s;
  font-size: 14px;
}
.quiz-opt:hover { background: rgba(88,166,255,0.10); border-color: var(--accent); }
.quiz-opt.chosen { background: rgba(88,166,255,0.18); border-color: var(--accent); }
.quiz-opt.correct {
  background: rgba(86,211,100,0.18);
  border-color: var(--green);
  color: #c5f3c5;
}
.quiz-opt.wrong {
  background: rgba(255,107,107,0.15);
  border-color: var(--red);
  color: #ffc0c0;
}
.quiz-opt.disabled { cursor: default; }
.quiz-feedback {
  margin-top: 10px;
  font-size: 13.5px;
  padding: 10px 14px;
  border-radius: 6px;
  background: var(--bg-3);
  border-left: 3px solid var(--accent);
  display: none;
}
.quiz-feedback.show { display: block; }
.quiz-feedback b { color: var(--accent); }

.score-bar {
  position: sticky;
  top: 56px;
  z-index: 50;
  background: rgba(13,17,23,0.92);
  backdrop-filter: blur(10px);
  border: 1px solid var(--border);
  border-radius: 10px;
  padding: 10px 16px;
  margin: 14px 0 18px;
  display: flex;
  gap: 18px;
  align-items: center;
  flex-wrap: wrap;
  font-size: 14px;
}
.score-bar .score-pill {
  background: var(--bg-3);
  border: 1px solid var(--border);
  border-radius: 14px;
  padding: 4px 12px;
}
.score-bar .score-pill .num { color: var(--accent); font-weight: 700; }
.score-bar button {
  background: var(--accent);
  color: var(--bg);
  border: none;
  border-radius: 6px;
  padding: 5px 12px;
  font-weight: 600;
  cursor: pointer;
  font-size: 13px;
}
.score-bar button:hover { background: #79b8ff; }
.score-bar button.secondary {
  background: var(--bg-3);
  color: var(--text);
  border: 1px solid var(--border);
}

.topic-tabs {
  display: flex;
  flex-wrap: wrap;
  gap: 6px;
  margin: 14px 0;
}
.topic-tabs button {
  background: var(--bg-2);
  border: 1px solid var(--border);
  color: var(--text-dim);
  padding: 6px 14px;
  border-radius: 18px;
  cursor: pointer;
  font-size: 13px;
  font-weight: 500;
  transition: all 0.12s;
}
.topic-tabs button:hover { color: var(--text); }
.topic-tabs button.active {
  background: var(--accent);
  color: var(--bg);
  border-color: var(--accent);
  font-weight: 600;
}

.quiz-topic { display: none; }
.quiz-topic.active { display: block; }

/* ===== Flashcards ===== */
.flash-stage {
  display: flex;
  flex-direction: column;
  align-items: center;
  margin: 22px auto;
  max-width: 720px;
}
.flashcard {
  width: 100%;
  height: 320px;
  perspective: 1400px;
  cursor: pointer;
  margin-bottom: 16px;
}
.flashcard-inner {
  position: relative;
  width: 100%;
  height: 100%;
  transition: transform 0.55s cubic-bezier(0.4, 0.2, 0.2, 1);
  transform-style: preserve-3d;
}
.flashcard.flipped .flashcard-inner { transform: rotateY(180deg); }
.flash-face {
  position: absolute;
  inset: 0;
  backface-visibility: hidden;
  border-radius: 14px;
  border: 1px solid var(--border);
  padding: 28px;
  display: flex;
  flex-direction: column;
  justify-content: center;
  align-items: center;
  text-align: center;
  font-size: 17px;
  overflow: auto;
}
.flash-front {
  background: linear-gradient(135deg, var(--bg-2), var(--bg-3));
  font-weight: 600;
}
.flash-back {
  background: linear-gradient(135deg, rgba(88,166,255,0.10), rgba(86,211,100,0.06));
  transform: rotateY(180deg);
  font-size: 15px;
  line-height: 1.55;
  font-weight: 400;
}
.flash-back .answer-key {
  font-weight: 700;
  color: var(--green);
  font-size: 17px;
  margin-bottom: 10px;
}
.flash-back .detail {
  color: var(--text-dim);
  font-size: 14px;
  margin-top: 8px;
}
.flash-tag {
  position: absolute;
  top: 12px;
  right: 14px;
  font-size: 11px;
  text-transform: uppercase;
  letter-spacing: 0.6px;
  color: var(--text-dim);
  background: rgba(255,255,255,0.05);
  padding: 2px 8px;
  border-radius: 8px;
}
.flash-controls {
  display: flex;
  gap: 10px;
  flex-wrap: wrap;
  justify-content: center;
}
.flash-controls button {
  background: var(--bg-3);
  border: 1px solid var(--border);
  color: var(--text);
  padding: 8px 18px;
  border-radius: 8px;
  cursor: pointer;
  font-size: 14px;
  font-weight: 500;
  transition: all 0.12s;
}
.flash-controls button:hover { background: var(--bg-2); border-color: var(--accent); }
.flash-controls button.primary {
  background: var(--accent);
  color: var(--bg);
  border-color: var(--accent);
  font-weight: 600;
}
.flash-controls button.primary:hover { background: #79b8ff; }
.flash-controls button.known { background: rgba(86,211,100,0.15); border-color: var(--green); color: #c5f3c5; }
.flash-controls button.unknown { background: rgba(255,107,107,0.10); border-color: var(--red); color: #ffc0c0; }

.flash-meta {
  text-align: center;
  color: var(--text-dim);
  font-size: 13px;
  margin: 12px 0;
}
.flash-progress {
  width: 100%;
  height: 6px;
  background: var(--bg-3);
  border-radius: 3px;
  overflow: hidden;
  margin-top: 10px;
}
.flash-progress .bar {
  height: 100%;
  background: linear-gradient(90deg, var(--accent), var(--green));
  width: 0%;
  transition: width 0.3s;
}

/* ===== Book-style structured layout ===== */
.chapter-toc {
  background: var(--bg-2);
  border: 1px solid var(--border);
  border-radius: 10px;
  padding: 18px 22px;
  margin: 18px 0 28px;
  font-size: 14px;
}
.chapter-toc h4 {
  margin: 0 0 8px;
  font-size: 12px;
  text-transform: uppercase;
  letter-spacing: 0.8px;
  color: var(--text-dim);
}
.chapter-toc ol { margin: 4px 0; padding-left: 24px; }
.chapter-toc ol ol { padding-left: 22px; margin: 2px 0; }
.chapter-toc a { color: var(--accent); text-decoration: none; }
.chapter-toc a:hover { text-decoration: underline; }
.chapter-toc li { margin: 3px 0; }
.chapter-toc .sub { color: var(--text-dim); font-size: 13px; }

h2.chapter {
  font-size: 22px;
  margin: 44px 0 4px;
  padding: 0;
  border: none;
  color: var(--text);
}
h2.chapter .num {
  color: var(--accent);
  font-weight: 700;
  margin-right: 10px;
}
h2.chapter + .chapter-intro {
  color: var(--text-dim);
  font-size: 14.5px;
  padding-bottom: 12px;
  border-bottom: 1px solid var(--border);
  margin-bottom: 18px;
}

h3.section {
  font-size: 17px;
  margin: 24px 0 8px;
  color: var(--text);
  display: flex;
  align-items: baseline;
  gap: 10px;
}
h3.section .num {
  color: var(--accent);
  font-family: "Cascadia Code", monospace;
  font-size: 14px;
  font-weight: 700;
  background: rgba(88,166,255,0.10);
  padding: 2px 8px;
  border-radius: 4px;
  letter-spacing: 0.4px;
}

h4.subsection {
  font-size: 14px;
  margin: 16px 0 6px;
  color: var(--text);
  font-weight: 600;
  text-transform: none;
  letter-spacing: 0;
}
h4.subsection .num {
  color: var(--text-dim);
  font-family: "Cascadia Code", monospace;
  font-size: 13px;
  margin-right: 8px;
}

.def-box {
  border-left: 4px solid var(--accent);
  background: linear-gradient(90deg, rgba(88,166,255,0.10), transparent);
  padding: 12px 16px;
  margin: 12px 0;
  border-radius: 0 8px 8px 0;
}
.def-box .lbl {
  font-size: 11px;
  text-transform: uppercase;
  letter-spacing: 1px;
  color: var(--accent);
  font-weight: 700;
  margin-bottom: 4px;
}
.def-box .term {
  font-weight: 700;
  margin-right: 6px;
}

.takeaway {
  background: rgba(86,211,100,0.08);
  border: 1px solid rgba(86,211,100,0.30);
  border-radius: 8px;
  padding: 12px 16px;
  margin: 14px 0;
  font-size: 14px;
}
.takeaway .lbl {
  font-size: 11px;
  text-transform: uppercase;
  letter-spacing: 1px;
  color: var(--green);
  font-weight: 700;
  margin-bottom: 4px;
}

.why-care {
  background: rgba(227,179,65,0.06);
  border-left: 3px solid var(--yellow);
  padding: 10px 14px;
  margin: 10px 0;
  border-radius: 0 6px 6px 0;
  font-size: 13.5px;
}
.why-care .lbl {
  font-size: 11px;
  text-transform: uppercase;
  letter-spacing: 1px;
  color: var(--yellow);
  font-weight: 700;
  margin-right: 6px;
}

.step-list {
  counter-reset: step;
  list-style: none;
  padding: 0;
  margin: 12px 0;
}
.step-list li {
  counter-increment: step;
  padding: 8px 14px 8px 44px;
  position: relative;
  margin-bottom: 6px;
  background: var(--bg-3);
  border-radius: 6px;
  border-left: 3px solid var(--border);
}
.step-list li::before {
  content: counter(step);
  position: absolute;
  left: 12px;
  top: 8px;
  background: var(--accent);
  color: var(--bg);
  width: 22px;
  height: 22px;
  border-radius: 50%;
  font-size: 12px;
  font-weight: 700;
  display: flex;
  align-items: center;
  justify-content: center;
}

/* Instruction-format bit diagram */
.instr-fmt {
  display: grid;
  grid-template-columns: 100px 1fr;
  align-items: center;
  gap: 12px;
  margin: 8px 0;
  font-family: "Cascadia Code", monospace;
  font-size: 12.5px;
}
.instr-fmt .fmt-name {
  text-align: right;
  font-weight: 700;
  color: var(--accent);
}
.instr-fmt .fields {
  display: flex;
  border: 1px solid var(--border);
  border-radius: 4px;
  overflow: hidden;
}
.instr-fmt .fields .f {
  padding: 5px 4px;
  text-align: center;
  border-right: 1px solid var(--border);
  font-size: 11px;
  line-height: 1.3;
}
.instr-fmt .fields .f:last-child { border-right: none; }
.instr-fmt .fields .f .w { display: block; color: var(--text-dim); font-size: 10px; margin-top: 2px; }
.instr-fmt .fields .f.op { background: rgba(247,129,102,0.18); color: #ffb09a; }
.instr-fmt .fields .f.rd { background: rgba(86,211,100,0.18); color: #b8eebb; }
.instr-fmt .fields .f.rs { background: rgba(88,166,255,0.16); color: #a8c8ff; }
.instr-fmt .fields .f.imm { background: rgba(227,179,65,0.18); color: #f3d68a; }
.instr-fmt .fields .f.fn { background: rgba(188,140,255,0.18); color: #d5b0ff; }

/* Datapath SVG framing */
.dp-frame {
  background: var(--bg-2);
  border: 1px solid var(--border);
  border-radius: 10px;
  padding: 16px;
  margin: 14px 0;
  overflow-x: auto;
}
.dp-frame .caption {
  text-align: center;
  color: var(--text-dim);
  font-size: 13px;
  margin-top: 8px;
}

/* Compact comparison table */
.cmp {
  width: 100%;
  margin: 10px 0;
  font-size: 14px;
  border-collapse: collapse;
}
.cmp th, .cmp td {
  padding: 9px 12px;
  border-bottom: 1px solid var(--border);
}
.cmp th { background: var(--bg-3); color: var(--accent); text-align: left; }
.cmp .yes { color: var(--green); font-weight: 600; }
.cmp .no { color: var(--red); }
.cmp .maybe { color: var(--yellow); }