/* ═══════════════════════════════════════════════
   DISK SCHEDULING — styles.css
═══════════════════════════════════════════════ */

@import url('https://fonts.googleapis.com/css2?family=Lora:ital,wght@0,400;0,600;1,400;1,600&family=DM+Mono:wght@300;400;500&family=DM+Sans:ital,opsz,wght@0,9..40,300;0,9..40,400;0,9..40,500;0,9..40,600;1,9..40,300;1,9..40,400&display=swap');

/* ── TOKENS ─────────────────────────────────── */
:root {
  --bg:      #0b0c10;
  --s1:      #11121a;
  --s2:      #181925;
  --s3:      #1e2030;
  --border:  #262840;
  --border2: #343660;
  --accent:  #5b8dee;
  --accent2: #8db4f5;
  --orange:  #f07b3f;
  --teal:    #38d9a9;
  --red:     #ff6b6b;
  --green:   #51cf66;
  --yellow:  #ffd43b;
  --text:    #e4e6f0;
  --muted:   #5a5d7a;
  --dim:     #3a3d58;
  --serif:   'Lora', Georgia, serif;
  --mono:    'DM Mono', monospace;
  --sans:    'DM Sans', system-ui, sans-serif;
}

/* ── RESET ──────────────────────────────────── */
*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }
html { scroll-behavior: smooth; }
body {
  background: var(--bg);
  color: var(--text);
  font-family: var(--sans);
  font-size: 16px;
  line-height: 1.75;
  overflow-x: hidden;
}

/* ── SECTION NAV DOTS ────────────────────────── */
#section-nav {
  position: fixed;
  left: 2.5rem;
  top: 50%;
  transform: translateY(-50%);
  z-index: 200;
  display: flex;
  flex-direction: column;
  align-items: flex-start;
  gap: 0;
}
.nav-item {
  display: flex;
  align-items: center;
  gap: 10px;
  padding: 6px 0;
  cursor: pointer;
}
.nav-dot-wrap {
  position: relative;
  width: 12px;
  display: flex;
  align-items: center;
  justify-content: center;
}
.nav-connector {
  position: absolute;
  left: 50%;
  top: 100%;
  transform: translateX(-50%);
  width: 1px;
  height: 18px;
  background: var(--dim);
  z-index: 0;
  transition: background 0.4s;
}
.nav-connector.filled { background: var(--accent); }
.nav-dot {
  width: 8px;
  height: 8px;
  border-radius: 50%;
  border: 1.5px solid var(--dim);
  background: transparent;
  transition: all 0.35s cubic-bezier(0.34, 1.56, 0.64, 1);
  position: relative;
  z-index: 1;
  flex-shrink: 0;
}
.nav-dot.active {
  width: 10px;
  height: 10px;
  border-color: var(--accent);
  background: var(--accent);
  box-shadow: 0 0 0 3px rgba(91, 141, 238, 0.2);
}
.nav-dot.done {
  border-color: var(--accent);
  background: var(--accent);
  opacity: 0.55;
}
.nav-label {
  font-family: var(--mono);
  font-size: 10px;
  letter-spacing: 0.08em;
  color: var(--muted);
  white-space: nowrap;
  opacity: 0;
  transform: translateX(-4px);
  transition: opacity 0.2s, transform 0.2s, color 0.2s;
  pointer-events: none;
}
.nav-item:hover .nav-label,
.nav-item.active-item .nav-label {
  opacity: 1;
  transform: translateX(0);
  color: var(--accent2);
}
@media (max-width: 768px) { #section-nav { display: none; } }

/* ── LAYOUT ─────────────────────────────────── */
.col { max-width: 700px; margin: 0 auto; padding: 0 2rem; }
section { padding: 100px 0 80px; border-bottom: 1px solid var(--border); position: relative; }
section:last-of-type { border-bottom: none; }

/* ── REVEAL ─────────────────────────────────── */
.r { opacity: 0; transform: translateY(18px); transition: opacity 0.55s ease, transform 0.55s ease; }
.r.in { opacity: 1; transform: none; }
.d1 { transition-delay: 0.08s; }
.d2 { transition-delay: 0.16s; }
.d3 { transition-delay: 0.24s; }
.d4 { transition-delay: 0.32s; }
.d5 { transition-delay: 0.40s; }

/* ── TYPOGRAPHY ─────────────────────────────── */
.serif  { font-family: var(--serif); }
.mono   { font-family: var(--mono); }
.tag {
  display: inline-block;
  font-family: var(--mono);
  font-size: 10px;
  letter-spacing: 0.14em;
  text-transform: uppercase;
  color: var(--accent2);
  border: 1px solid rgba(91, 141, 238, 0.3);
  background: rgba(91, 141, 238, 0.08);
  padding: 3px 12px;
  border-radius: 100px;
  margin-bottom: 1.5rem;
}
.display {
  font-family: var(--serif);
  font-size: clamp(2.4rem, 5.5vw, 4rem);
  font-weight: 600;
  line-height: 1.1;
  letter-spacing: -0.02em;
}
.h2 { font-family: var(--serif); font-size: clamp(1.8rem, 4vw, 2.8rem); font-weight: 600; line-height: 1.2; letter-spacing: -0.015em; }
.h3 { font-size: 1.05rem; font-weight: 600; }
.lead { font-size: 1.05rem; color: #8a8db0; line-height: 1.85; font-weight: 300; }
.body { font-size: 0.92rem; color: #7a7d9e; line-height: 1.9; }
em.hi { font-style: italic; color: var(--accent2); }
strong { color: var(--text); font-weight: 600; }
code {
  font-family: var(--mono);
  font-size: 0.8em;
  background: rgba(91, 141, 238, 0.12);
  color: var(--accent2);
  padding: 1px 6px;
  border-radius: 4px;
}

/* ── SURFACES ───────────────────────────────── */
.card  { background: var(--s1); border: 1px solid var(--border); border-radius: 14px; }
.card2 { background: var(--s2); border: 1px solid var(--border); border-radius: 10px; }

/* ── PILLS ──────────────────────────────────── */
.pill-good { display: inline-block; font-family: var(--mono); font-size: 10px; padding: 2px 9px; border-radius: 100px; background: rgba(81,207,102,0.1);  color: var(--green);  border: 1px solid rgba(81,207,102,0.25); }
.pill-bad  { display: inline-block; font-family: var(--mono); font-size: 10px; padding: 2px 9px; border-radius: 100px; background: rgba(255,107,107,0.1); color: var(--red);    border: 1px solid rgba(255,107,107,0.25); }
.pill-mid  { display: inline-block; font-family: var(--mono); font-size: 10px; padding: 2px 9px; border-radius: 100px; background: rgba(253,196,59,0.1);  color: var(--yellow); border: 1px solid rgba(253,196,59,0.25); }
.pill-info { display: inline-block; font-family: var(--mono); font-size: 10px; padding: 2px 9px; border-radius: 100px; background: rgba(91,141,238,0.1);  color: var(--accent2);border: 1px solid rgba(91,141,238,0.25); }

/* ── CALLOUTS ───────────────────────────────── */
.cl        { border-left: 2.5px solid var(--accent);  padding: .9rem 1.2rem; background: rgba(91,141,238,0.05);  border-radius: 0 8px 8px 0; }
.cl-orange { border-left: 2.5px solid var(--orange);  padding: .9rem 1.2rem; background: rgba(240,123,63,0.05);  border-radius: 0 8px 8px 0; }
.cl-red    { border-left: 2.5px solid var(--red);     padding: .9rem 1.2rem; background: rgba(255,107,107,0.05); border-radius: 0 8px 8px 0; }
.cl-green  { border-left: 2.5px solid var(--teal);    padding: .9rem 1.2rem; background: rgba(56,217,169,0.05);  border-radius: 0 8px 8px 0; }

/* ── BUTTONS ────────────────────────────────── */
.btn {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  font-family: var(--mono);
  font-size: 12px;
  font-weight: 500;
  padding: 8px 18px;
  border-radius: 8px;
  border: 1.5px solid var(--border2);
  background: transparent;
  color: var(--text);
  cursor: pointer;
  transition: all 0.15s;
  letter-spacing: 0.04em;
}
.btn:hover { background: var(--s2); border-color: var(--accent); color: var(--accent2); }
.btn:disabled { opacity: 0.3; cursor: not-allowed; }
.btn.primary { background: var(--accent); border-color: var(--accent); color: white; }
.btn.primary:hover { background: #4a7bde; }
.btn.primary:disabled { background: var(--dim); border-color: var(--dim); }

/* ── DISK DRILL-DOWN ─────────────────────────── */
#drill-stage {
  position: relative;
  width: 100%;
  background: var(--s1);
  border: 1px solid var(--border);
  border-radius: 16px;
  overflow: hidden;
}
.view-tabs {
  display: flex;
  gap: 0;
  border-bottom: 1px solid var(--border);
}
.view-tab {
  flex: 1;
  padding: 10px 16px;
  font-family: var(--mono);
  font-size: 11px;
  letter-spacing: 0.08em;
  text-align: center;
  cursor: pointer;
  color: var(--muted);
  border: none;
  background: transparent;
  transition: all 0.2s;
  border-bottom: 2px solid transparent;
}
.view-tab.active {
  color: var(--accent2);
  border-bottom-color: var(--accent);
  background: rgba(91,141,238,0.05);
}
.drill-canvas-layer {
  display: none;
  width: 100%;
}
.drill-canvas-layer.active { display: block; }
.step-pills {
  display: flex;
  gap: 6px;
  flex-wrap: wrap;
  padding: 1rem 1.25rem;
  border-top: 1px solid var(--border);
}
.step-pill {
  font-family: var(--mono);
  font-size: 10px;
  padding: 4px 12px;
  border-radius: 100px;
  border: 1px solid var(--border2);
  color: var(--muted);
  cursor: pointer;
  transition: all 0.2s;
  background: transparent;
}
.step-pill.active {
  background: var(--accent);
  border-color: var(--accent);
  color: white;
}
.step-pill.done {
  border-color: rgba(91,141,238,0.4);
  color: var(--accent2);
}
#drill-caption-box {
  padding: .75rem 1.25rem;
  font-size: 13px;
  color: #8a8db0;
  min-height: 48px;
  border-top: 1px solid var(--border);
  font-family: var(--sans);
  line-height: 1.6;
}

/* ── AXIS (set piece + algo cards) ──────────── */
.axis-wrap {
  position: relative;
  height: 54px;
  background: var(--s2);
  border: 1px solid var(--border);
  border-radius: 10px;
  overflow: visible;
}
.axis-line {
  position: absolute;
  top: 50%;
  left: 14px;
  right: 14px;
  height: 1px;
  background: var(--border2);
  transform: translateY(-50%);
}
.axis-head {
  position: absolute;
  top: 6px;
  width: 2px;
  height: 42px;
  background: var(--orange);
  border-radius: 1px;
  box-shadow: 0 0 8px var(--orange);
  transition: left 0.6s cubic-bezier(0.4, 0, 0.2, 1);
}
.axis-head::after {
  content: '';
  position: absolute;
  bottom: -3px;
  left: 50%;
  transform: translateX(-50%);
  width: 10px;
  height: 10px;
  border-radius: 50%;
  background: var(--orange);
  box-shadow: 0 0 12px var(--orange);
}
.axis-req {
  position: absolute;
  top: 50%;
  transform: translate(-50%, -50%);
  width: 8px;
  height: 8px;
  border-radius: 50%;
  background: var(--s1);
  border: 1.5px solid var(--accent);
  transition: background 0.3s;
}
.axis-req.visited { background: var(--accent); border-color: var(--accent); }
.axis-head-lbl {
  position: absolute;
  top: -20px;
  left: 50%;
  transform: translateX(-50%);
  font-family: var(--mono);
  font-size: 9px;
  color: var(--orange);
  white-space: nowrap;
}

/* ── ALGO CARDS (expanded) ──────────────────── */
.algo-card {
  background: var(--s1);
  border: 1px solid var(--border);
  border-radius: 14px;
  padding: 1.5rem;
  transition: border-color 0.2s;
  margin-bottom: 2rem;
}
.algo-card:hover { border-color: var(--border2); }

.algo-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin-bottom: 1.25rem;
  flex-wrap: wrap;
  gap: .5rem;
}
.algo-title-group {
  display: flex;
  align-items: center;
  gap: .75rem;
}
.algo-section-label {
  font-family: var(--mono);
  font-size: 9px;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  color: var(--muted);
  margin-bottom: .3rem;
  margin-top: 1rem;
}
.algo-divider {
  height: 1px;
  background: var(--border);
  margin: 1.1rem 0;
}

/* seek trace chart container */
.seek-chart-wrap {
  position: relative;
  height: 220px;
  margin-bottom: .5rem;
}

/* adv/disadv bullets */
.adv-list {
  list-style: none;
  display: flex;
  flex-direction: column;
  gap: 6px;
  margin: 0;
  padding: 0;
}
.adv-list li {
  display: flex;
  gap: 10px;
  align-items: flex-start;
  font-size: 13px;
  line-height: 1.55;
  color: #7a7d9e;
}
.adv-list li .bullet {
  flex-shrink: 0;
  width: 16px;
  height: 16px;
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 9px;
  font-weight: 700;
  margin-top: 1px;
}
.bullet-good { background: rgba(81,207,102,0.15); color: var(--green); }
.bullet-bad  { background: rgba(255,107,107,0.15); color: var(--red); }

/* ── SCORE BARS ─────────────────────────────── */
.score-bar-bg   { flex: 1; height: 6px; background: var(--s3); border-radius: 3px; overflow: hidden; }
.score-bar-fill { height: 100%; border-radius: 3px; transition: width 1s cubic-bezier(0.4, 0, 0.2, 1); width: 0; }

/* ── STEP LOG ───────────────────────────────── */
#sp-log {
  background: var(--s2);
  border: 1px solid var(--border);
  border-radius: 10px;
  padding: 1rem 1.25rem;
  height: 160px;
  overflow-y: auto;
  font-family: var(--mono);
  font-size: 12px;
  line-height: 2;
}
#sp-log::-webkit-scrollbar { width: 3px; }
#sp-log::-webkit-scrollbar-track { background: var(--s3); }
#sp-log::-webkit-scrollbar-thumb { background: var(--border2); border-radius: 2px; }

/* ── TERM GRID ──────────────────────────────── */
.term-grid { display: grid; grid-template-columns: 1fr 1fr; gap: 1px; background: var(--border); border-radius: 12px; overflow: hidden; }
.term-cell { background: var(--s1); padding: 1.1rem 1.25rem; }
@media (max-width: 540px) { .term-grid { grid-template-columns: 1fr; } }

/* ── TABLE ──────────────────────────────────── */
.ctab { width: 100%; border-collapse: collapse; font-size: 13px; }
.ctab th { font-family: var(--mono); font-size: 9px; letter-spacing: 0.1em; text-transform: uppercase; color: var(--muted); padding: 10px 14px; text-align: left; border-bottom: 1px solid var(--border); }
.ctab td { padding: 12px 14px; border-bottom: 1px solid rgba(38,40,64,0.6); color: #7a7d9e; vertical-align: middle; }
.ctab tr:last-child td { border-bottom: none; }
.ctab tr.best-row td { background: rgba(56,217,169,0.04); }

/* ── DS ANIMATION ───────────────────────────── */
#ds-anim {
  position: relative;
  height: 90px;
  overflow: hidden;
}
.ds-req-bubble {
  position: absolute;
  top: 50%;
  transform: translateY(-50%);
  background: var(--s2);
  border: 1px solid var(--border2);
  border-radius: 8px;
  font-family: var(--mono);
  font-size: 11px;
  padding: 4px 10px;
  color: var(--accent2);
  white-space: nowrap;
  transition: left 0.5s ease, opacity 0.4s ease;
}
#ds-cpu {
  position: absolute;
  right: 0;
  top: 50%;
  transform: translateY(-50%);
  background: var(--s3);
  border: 1.5px solid var(--accent);
  border-radius: 10px;
  width: 56px;
  height: 56px;
  display: flex;
  align-items: center;
  justify-content: center;
  font-family: var(--mono);
  font-size: 9px;
  color: var(--accent2);
  letter-spacing: .08em;
  box-shadow: 0 0 0 3px rgba(91,141,238,0.12);
}

/* ── CTA ────────────────────────────────────── */
.cta-wrap {
  background: linear-gradient(135deg, var(--s2) 0%, var(--s1) 100%);
  border: 1px solid var(--border2);
  border-radius: 24px;
  padding: 3rem 2.5rem;
  text-align: center;
  position: relative;
  overflow: hidden;
}
.cta-wrap::before {
  content: '';
  position: absolute;
  top: -80px;
  left: 50%;
  transform: translateX(-50%);
  width: 400px;
  height: 200px;
  background: radial-gradient(ellipse, rgba(91,141,238,0.15) 0%, transparent 70%);
  pointer-events: none;
}
.cta-btn {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  background: var(--accent);
  color: white;
  font-weight: 600;
  font-size: 15px;
  padding: 14px 32px;
  border-radius: 12px;
  text-decoration: none;
  border: none;
  cursor: pointer;
  transition: background 0.2s, transform 0.15s;
}
.cta-btn:hover { background: #4a7bde; transform: translateY(-2px); }

/* ── ANIMATIONS ─────────────────────────────── */
@keyframes bob { 0%,100% { transform: translateY(0); } 55% { transform: translateY(7px); } }
.bob { animation: bob 2s ease-in-out infinite; }

@keyframes fadeUp { from { opacity: 0; transform: translateY(10px); } to { opacity: 1; transform: none; } }
.fadeup { animation: fadeUp 0.4s ease forwards; }

@keyframes spin { from { transform: rotate(0deg); } to { transform: rotate(360deg); } }

@keyframes slideRight {
  from { transform: translateX(-12px); opacity: 0; }
  to   { transform: translateX(0);     opacity: 1; }
}

/* ── TOP NAVIGATION BAR ─────────────────────── */
#top-nav {
  position: fixed;
  top: 0; left: 0; right: 0;
  z-index: 300;
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 0;
  padding: 0 2rem;
  height: 52px;
  background: rgba(11,12,16,0.88);
  backdrop-filter: blur(10px);
  border-bottom: 1px solid var(--border);
}
.tnav-item {
  display: flex;
  align-items: center;
  gap: 10px;
  cursor: pointer;
  padding: 0 4px;
}
.tnav-bubble {
  width: 28px; height: 28px;
  border-radius: 50%;
  border: 1.5px solid var(--dim);
  display: flex; align-items: center; justify-content: center;
  font-family: var(--mono); font-size: 11px; font-weight: 500;
  color: var(--muted);
  transition: all 0.3s;
  flex-shrink: 0;
}
.tnav-label {
  font-family: var(--mono); font-size: 10px;
  letter-spacing: 0.1em; text-transform: uppercase;
  color: var(--muted); white-space: nowrap;
  transition: color 0.3s;
}
.tnav-arrow {
  color: var(--dim); font-size: 12px;
  margin: 0 6px;
  flex-shrink: 0;
  transition: color 0.3s;
}
/* active state */
.tnav-item.t-active .tnav-bubble {
  border-color: var(--accent);
  background: var(--accent);
  color: white;
  box-shadow: 0 0 0 3px rgba(91,141,238,0.2);
}
.tnav-item.t-active .tnav-label { color: var(--text); font-weight: 600; }
/* done state */
.tnav-item.t-done .tnav-bubble {
  border-color: var(--accent);
  background: rgba(91,141,238,0.2);
  color: var(--accent2);
}
.tnav-item.t-done .tnav-label { color: var(--accent2); }
.tnav-item.t-done + .tnav-arrow { color: var(--accent); }
/* simulator item (play icon) */
.tnav-play {
  width: 28px; height: 28px;
  border-radius: 50%;
  border: 1.5px solid var(--dim);
  display: flex; align-items: center; justify-content: center;
  color: var(--muted);
  transition: all 0.3s;
}
.tnav-item.t-active .tnav-play {
  border-color: var(--teal);
  background: var(--teal);
  color: #0b0c10;
  box-shadow: 0 0 0 3px rgba(56,217,169,0.2);
}
.tnav-item.t-done .tnav-play { border-color: var(--teal); color: var(--teal); }
@media (max-width: 600px) { .tnav-label { display: none; } #top-nav { gap: 0; } }

/* ── GROUPED LEFT NAV ───────────────────────── */
/* groups: FOUNDATIONS (s0-s1), SCHEDULING (s2-s3), ALGORITHMS (s4-s5), SCOREBOARD+CTA (s6-s7) */
.nav-group {
  display: flex;
  flex-direction: column;
  gap: 0;
}
.nav-group-label {
  font-family: var(--mono);
  font-size: 8px;
  letter-spacing: 0.14em;
  text-transform: uppercase;
  color: var(--dim);
  padding: 0 0 4px 22px;
  margin-top: 8px;
}
.nav-group:first-child .nav-group-label { margin-top: 0; }

/* ── BODY OFFSET FOR TOP NAV ────────────────── */
body { padding-top: 52px; }
section { scroll-margin-top: 52px; }

/* ── PROBLEM SECTION — VISUAL REDESIGN ─────── */
.seek-compare-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 1px;
  background: var(--border);
  border-radius: 14px;
  overflow: hidden;
  margin-bottom: 1.5rem;
}
.seek-compare-cell {
  background: var(--s1);
  padding: 1.5rem;
  display: flex;
  flex-direction: column;
  gap: .5rem;
}
.seek-number {
  font-family: var(--mono);
  font-size: 3rem;
  font-weight: 500;
  line-height: 1;
}
.seek-number.bad  { color: var(--red); }
.seek-number.good { color: var(--teal); }
.seek-sublabel {
  font-family: var(--mono);
  font-size: 9px;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  color: var(--muted);
}
.seek-bar-row {
  display: flex;
  align-items: center;
  gap: 8px;
  margin-top: .25rem;
}
.seek-bar-track {
  flex: 1;
  height: 4px;
  background: var(--s3);
  border-radius: 2px;
  overflow: hidden;
}
.seek-bar-fill {
  height: 100%;
  border-radius: 2px;
}
/* zigzag SVG diagram */
.problem-svg-wrap {
  background: var(--s2);
  border: 1px solid var(--border);
  border-radius: 10px;
  padding: .75rem 1rem .5rem;
  margin-bottom: 1.5rem;
}

/* ── KEY TERMS — REDESIGNED ─────────────────── */
.term-grid-new {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 1rem;
  margin-bottom: 0;
}
@media (max-width: 540px) { .term-grid-new { grid-template-columns: 1fr; } }
.term-card {
  background: var(--s1);
  border: 1px solid var(--border);
  border-radius: 14px;
  padding: 1.4rem;
  position: relative;
  overflow: hidden;
  transition: border-color 0.2s, transform 0.2s;
}
.term-card:hover { border-color: var(--border2); transform: translateY(-2px); }
.term-card-icon {
  width: 36px; height: 36px;
  border-radius: 10px;
  display: flex; align-items: center; justify-content: center;
  font-size: 17px;
  margin-bottom: .85rem;
  flex-shrink: 0;
}
.term-card-accent {
  position: absolute;
  top: 0; right: 0;
  width: 80px; height: 80px;
  border-radius: 50%;
  opacity: 0.06;
  transform: translate(30px, -30px);
}
.term-card-kw {
  font-family: var(--mono);
  font-size: 9px;
  letter-spacing: 0.14em;
  text-transform: uppercase;
  margin-bottom: .3rem;
}
.term-card-title {
  font-size: 1rem;
  font-weight: 600;
  margin-bottom: .35rem;
  color: var(--text);
}
.term-card-body {
  font-size: 12px;
  color: #7a7d9e;
  line-height: 1.65;
}
.term-formula {
  font-family: var(--mono);
  font-size: 11px;
  background: var(--s2);
  border: 1px solid var(--border2);
  border-radius: 6px;
  padding: 5px 10px;
  margin-top: .5rem;
  color: var(--accent2);
  display: inline-block;
}

/* ── ALGO CARD COLLAPSIBLE ──────────────────── */
.algo-card { cursor: default; }
.algo-card-header {
  cursor: pointer;
  user-select: none;
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding-bottom: .75rem;
}
.algo-card-chevron {
  font-size: 12px;
  color: var(--muted);
  transition: transform 0.3s;
  flex-shrink: 0;
}
.algo-card-chevron.open { transform: rotate(180deg); }
.algo-card-body {
  overflow: hidden;
  transition: max-height 0.4s ease, opacity 0.3s ease;
  max-height: 0;
  opacity: 0;
}
.algo-card-body.open {
  max-height: 2000px;
  opacity: 1;
}