/* ===================================================================
   Linguagens Formais e Autômatos – site.css
   Dark-themed · Glassmorphism · Cyan/Teal accent
   =================================================================== */

/* ── Design Tokens ────────────────────────────────────────────────── */
:root{
  --bg:#0b0d12;
  --bg-soft:#111722;
  --panel:#151b26;
  --panel-2:#1c2533;
  --text:#eef4ff;
  --muted:#a8b4c7;
  --line:#344256;
  --accent:#22c8d8;          /* cyan/teal – cor primária */
  --accent-dark:#179ba8;
  --accent-glow:rgba(34,200,216,.25);
  --blue:#4f8cff;
  --orange:#f5a524;
  --red:#ef4b4b;
  --purple:#a77cff;
  --green:#1db77f;
  --shadow:0 18px 48px rgba(0,0,0,.28);
}

/* ── Reset & Base ─────────────────────────────────────────────────── */
*{box-sizing:border-box}
html{scroll-behavior:smooth}
body{
  margin:0;
  background:linear-gradient(180deg,#0b0d12 0%,#0d1520 44%,#0b0d12 100%);
  color:var(--text);
  font-family:Inter,ui-sans-serif,system-ui,-apple-system,Segoe UI,Roboto,Arial,sans-serif;
  line-height:1.55;
}
a{color:inherit;text-decoration:none}
p{color:#d3dbea;margin:8px 0}
h1,h2,h3{margin:0;color:#fff;letter-spacing:0}
h1{font-size:clamp(2.2rem,4.6vw,4.9rem);line-height:1.02}
h2{font-size:clamp(1.6rem,2.6vw,2.4rem);line-height:1.12}
h3{font-size:1.16rem;line-height:1.25}

/* ── Utility ──────────────────────────────────────────────────────── */
.sr-only{
  position:absolute;
  width:1px;
  height:1px;
  padding:0;
  margin:-1px;
  overflow:hidden;
  clip:rect(0,0,0,0);
  white-space:nowrap;
  border:0;
}

/* ── Topbar ───────────────────────────────────────────────────────── */
.topbar{
  position:sticky;
  z-index:20;
  top:0;
  display:flex;
  align-items:center;
  justify-content:space-between;
  gap:18px;
  padding:14px clamp(18px,4vw,48px);
  background:rgba(11,13,18,.84);
  border-bottom:1px solid rgba(255,255,255,.07);
  backdrop-filter:blur(14px);
}
.brand{font-weight:850;font-size:1.05rem}

/* ── Navigation ───────────────────────────────────────────────────── */
.main-nav{display:flex;gap:8px;flex-wrap:wrap;justify-content:flex-end}
.main-nav a,.button,.tab-list button,.step-controls button{
  border:1px solid rgba(255,255,255,.1);
  background:rgba(255,255,255,.045);
  color:#f8fbff;
  border-radius:8px;
  padding:8px 12px;
  font:700 .9rem/1 Inter,system-ui,sans-serif;
  cursor:pointer;
}
.main-nav a:hover,.main-nav a.active,.button.primary,.tab-list button.active,.step-controls button:hover{
  background:var(--accent);
  border-color:var(--accent);
  color:#071111;
}

/* ── Main container ───────────────────────────────────────────────── */
main{width:min(1180px,calc(100% - 36px));margin:0 auto}

/* ── Hero ─────────────────────────────────────────────────────────── */
.hero{
  min-height:calc(100vh - 72px);
  display:grid;
  grid-template-columns:minmax(0,1.05fr) minmax(320px,.78fr);
  gap:34px;
  align-items:center;
  padding:56px 0;
}
.hero p{max-width:760px;font-size:1.08rem;color:#c7d3e6}
.hero-actions{display:flex;gap:10px;flex-wrap:wrap;margin-top:22px}
.button{display:inline-flex;align-items:center;justify-content:center;min-height:40px}

/* ── Hero Panel (automaton preview) ───────────────────────────────── */
.hero-panel{
  border:1px solid rgba(255,255,255,.09);
  background:linear-gradient(180deg,rgba(255,255,255,.05),rgba(255,255,255,.025)),var(--panel);
  border-radius:14px;
  padding:18px;
  box-shadow:var(--shadow);
}

/* ── Automaton preview (hero) ─────────────────────────────────────── */
.automaton-preview{
  position:relative;
  aspect-ratio:3/2;
  border-radius:10px;
  overflow:hidden;
  background:
    radial-gradient(circle at 22% 24%,rgba(34,200,216,.22),transparent 28%),
    radial-gradient(circle at 72% 70%,rgba(79,140,255,.18),transparent 28%),
    #0f1520;
}
.automaton-preview svg{position:absolute;inset:0;width:100%;height:100%}

/* State circles inside preview */
.automaton-preview .state{
  position:absolute;
  left:var(--x);
  top:var(--y);
  z-index:2;
  display:grid;
  place-items:center;
  width:38px;
  height:38px;
  transform:translate(-50%,-50%);
  border-radius:50%;
  background:#122030;
  border:2px solid #b7c7e6;
  font-weight:850;
  font-size:.82rem;
  color:var(--text);
  transition:border-color .25s ease,box-shadow .25s ease;
}
.automaton-preview .state.accepting{
  box-shadow:0 0 0 3px #122030, 0 0 0 5px #b7c7e6;
}

/* ── Mini Stats ───────────────────────────────────────────────────── */
.mini-stats{display:grid;grid-template-columns:repeat(3,1fr);gap:10px;margin-top:12px}
.stat{border:1px solid rgba(255,255,255,.08);background:var(--panel-2);border-radius:8px;padding:12px}
.stat strong{display:block;font-size:1.55rem}
.stat span{font-size:.82rem;color:var(--muted)}

/* ── Sections ─────────────────────────────────────────────────────── */
.section-shell{padding:22px 0 48px}
.section-shell.compact{padding-top:0}
.section-heading{display:flex;justify-content:space-between;gap:20px;align-items:end;margin-bottom:18px}
.section-heading p{max-width:620px;color:var(--muted)}
.section-heading.tight{align-items:start;display:block}

/* ── Cards Grids ──────────────────────────────────────────────────── */
.topic-grid,.animation-grid{display:grid;grid-template-columns:repeat(3,minmax(0,1fr));gap:14px}

.topic-card,.animation-card,.content-card,.exercise-card{
  border:1px solid rgba(255,255,255,.08);
  background:linear-gradient(180deg,rgba(255,255,255,.04),rgba(255,255,255,.015)),var(--panel);
  border-radius:10px;
  padding:16px;
  box-shadow:0 12px 32px rgba(0,0,0,.18);
}

.topic-card small,.source,.tag{color:#b9c8df;font-size:.82rem}
.source{display:inline-block;max-width:100%;overflow-wrap:anywhere;word-break:break-word}
.tag{
  display:inline-flex;
  align-items:center;
  border:1px solid rgba(255,255,255,.1);
  border-radius:7px;
  padding:2px 7px;
  background:rgba(255,255,255,.045);
  margin:2px 4px 2px 0;
}

/* ── App Layout (teoria / exercícios) ─────────────────────────────── */
.app-layout{
  display:grid;
  grid-template-columns:300px minmax(0,1fr);
  gap:22px;
  align-items:start;
  width:min(1480px,calc(100% - 28px));
  padding:24px 0 54px;
  transition:grid-template-columns .2s ease;
}
.app-layout.rail-collapsed{
  grid-template-columns:58px minmax(0,1fr);
}

/* ── Rail / Sidebar ───────────────────────────────────────────────── */
.rail{
  position:sticky;
  top:72px;
  max-height:calc(100vh - 92px);
  overflow:auto;
  border:1px solid rgba(255,255,255,.08);
  background:rgba(18,24,34,.9);
  border-radius:12px;
  padding:16px;
  transition:padding .2s ease,background .2s ease;
}
.rail h1{font-size:1.6rem}
.rail p{font-size:.92rem;color:var(--muted)}
.rail-head{display:flex;align-items:center;justify-content:space-between;gap:12px}

.rail-toggle{
  flex:0 0 auto;
  display:grid;
  place-items:center;
  width:34px;
  height:34px;
  border:1px solid rgba(255,255,255,.13);
  border-radius:8px;
  background:rgba(255,255,255,.055);
  cursor:pointer;
}
.rail-toggle:hover{border-color:var(--accent);background:rgba(34,200,216,.16)}

.rail-toggle-lines,.rail-toggle-lines::before,.rail-toggle-lines::after{
  display:block;
  width:16px;
  height:2px;
  border-radius:3px;
  background:#e9f3ff;
}
.rail-toggle-lines{position:relative}
.rail-toggle-lines::before,.rail-toggle-lines::after{content:"";position:absolute;left:0}
.rail-toggle-lines::before{top:-6px}
.rail-toggle-lines::after{top:6px}

.rail-content{transition:opacity .15s ease,transform .15s ease}
.rail.is-collapsed{padding:12px 8px;overflow:hidden}
.rail.is-collapsed .rail-head{justify-content:center}
.rail.is-collapsed .rail-title,.rail.is-collapsed .rail-content{
  width:0;height:0;opacity:0;overflow:hidden;pointer-events:none;transform:translateX(-8px);
}

/* ── Tab list ─────────────────────────────────────────────────────── */
.tab-list{display:flex;flex-direction:column;gap:7px;margin-top:14px}
.tab-list button{text-align:left;line-height:1.2;color:#d8e3f5}
.tab-list button.active{color:#071111}

/* ── Content Stage ────────────────────────────────────────────────── */
.content-stage{min-width:0}
.content-card{margin-bottom:16px}
.content-card h2{margin-bottom:4px}
.content-card h3{margin-top:18px}
.content-card ul,.content-card ol{color:#d7dfec;padding-left:20px}
.content-card li{margin:6px 0}

/* ── Formula / Code ───────────────────────────────────────────────── */
.formula{
  overflow:auto;
  border:1px solid rgba(255,255,255,.08);
  border-radius:8px;
  background:#090e18;
  color:#dff6ff;
  padding:10px 12px;
  font-family:ui-monospace,SFMono-Regular,Menlo,Consolas,monospace;
}

/* ── Visual Cards ─────────────────────────────────────────────────── */
.visual-grid{display:grid;gap:14px;margin-top:16px}
.visual-card{border:1px solid rgba(255,255,255,.08);border-radius:10px;background:#101620;padding:12px}

/* ── Graph Box (legacy compat) ────────────────────────────────────── */
.graph-box{
  min-height:320px;
  display:grid;
  place-items:center;
  border:1px solid rgba(255,255,255,.07);
  border-radius:8px;
  background:#0b1220;
  overflow:hidden;
}
.graph-box svg{
  display:block;
  width:100%;
  max-width:100%;
  height:auto;
  max-height:min(62vh,540px);
  min-height:260px;
  aspect-ratio:var(--graph-ratio,720 / 380);
}

/* ── Step Controls ────────────────────────────────────────────────── */
.step-controls{display:flex;align-items:center;gap:8px;margin-top:10px}
.step-controls span{flex:1;text-align:center;color:var(--muted);font-size:.9rem}
.step-text{margin-top:10px;border-left:3px solid var(--orange);padding-left:10px;color:#dce7f7}

/* ── Exercises ────────────────────────────────────────────────────── */
.exercise-list{display:grid;gap:16px}
.exercise-card{padding:0;overflow:hidden}
.exercise-head{display:flex;justify-content:space-between;gap:12px;align-items:start;padding:16px;border-bottom:1px solid rgba(255,255,255,.08)}
.exercise-body{display:block;padding:16px}
.solution-toggle{margin-top:16px}
.prompt{white-space:pre-line;color:#e1e8f5}
.question-list{margin:10px 0 0;padding-left:20px;color:#dce5f4}
.solution{border-top:1px solid rgba(255,255,255,.08);padding:16px;background:rgba(255,255,255,.025)}
.solution ol{padding-left:20px;color:#dce5f4}
.solution-graph{margin-top:14px}
.solution-graph h4{margin:0 0 10px;color:#fff;font-size:1rem}
.prompt-graph-grid{display:grid;grid-template-columns:repeat(auto-fit,minmax(260px,1fr));gap:12px;margin-top:14px}
.prompt-graph-grid .solution-graph{margin-top:0}
.prompt-graph-grid .graph-box{min-height:260px}

/* ── Table / Matrix ───────────────────────────────────────────────── */
.matrix-wrap{margin-top:16px;overflow:auto}
.matrix-wrap h3{margin-bottom:8px}
.table-scroll{margin-top:16px;overflow:auto}
.table-scroll h4{margin:0 0 8px;color:#fff;font-size:1rem}

/* ── Footer ───────────────────────────────────────────────────────── */
.footer{width:min(1180px,calc(100% - 36px));margin:0 auto;padding:28px 0 42px;color:var(--muted)}

/* ── SVG Typography ───────────────────────────────────────────────── */
.svg-label{font-family:Inter,Arial,sans-serif;font-size:12px;font-weight:800;fill:#eaf2ff}
.svg-muted{fill:#b6c3d8}


/* ===================================================================
   AUTOMATA-SPECIFIC STYLES
   =================================================================== */

/* ── Automaton Box ────────────────────────────────────────────────── */
.automaton-box{
  position:relative;
  min-height:320px;
  display:grid;
  place-items:center;
  border:1px solid rgba(34,200,216,.12);
  border-radius:10px;
  background:
    radial-gradient(ellipse 60% 50% at 50% 50%,rgba(34,200,216,.06),transparent),
    #0b1220;
  overflow:hidden;
  box-shadow:inset 0 1px 0 rgba(255,255,255,.04);
}
.automaton-box svg{
  display:block;
  width:100%;
  max-width:100%;
  height:auto;
  max-height:min(62vh,540px);
  min-height:260px;
  aspect-ratio:var(--automaton-ratio,720 / 380);
}

/* ── SVG Automaton States ─────────────────────────────────────────── */
.automaton-box .svg-state{
  fill:#132030;
  stroke:#6b849e;
  stroke-width:2;
  transition:fill .22s ease,stroke .22s ease,filter .22s ease;
}
.automaton-box .svg-state-label{
  font-family:Inter,Arial,sans-serif;
  font-size:13px;
  font-weight:800;
  fill:#eaf2ff;
  text-anchor:middle;
  dominant-baseline:central;
  pointer-events:none;
}

/* ── SVG Transitions ──────────────────────────────────────────────── */
.automaton-box .svg-transition{
  fill:none;
  stroke:#5e718d;
  stroke-width:2;
  stroke-linecap:round;
  transition:stroke .22s ease,stroke-width .22s ease;
}
.automaton-box .svg-transition-label{
  font-family:Inter,Arial,sans-serif;
  font-size:11px;
  font-weight:700;
  fill:#a8bdd5;
}
.automaton-box .svg-arrowhead{
  fill:#5e718d;
  transition:fill .22s ease;
}
/* Initial state arrow */
.automaton-box .svg-initial-arrow{
  fill:none;
  stroke:var(--accent);
  stroke-width:2;
  stroke-linecap:round;
}
.automaton-box .svg-initial-arrowhead{
  fill:var(--accent);
}

/* ── State: Active (animação de simulação) ────────────────────────── */
.state-active .svg-state,
.svg-state.state-active{
  fill:rgba(34,200,216,.2);
  stroke:var(--accent);
  stroke-width:2.5;
  filter:drop-shadow(0 0 10px rgba(34,200,216,.45));
}
.state-active .svg-state-label,
.svg-state.state-active + .svg-state-label{
  fill:#fff;
}

/* ── State: Accepting (estado de aceitação – duplo círculo) ───────── */
.state-accepting .svg-state,
.svg-state.state-accepting{
  stroke:#22c8d8;
  stroke-width:2;
}
/* segundo círculo interno para duplo-círculo */
.state-accepting .svg-state-inner,
.svg-state-inner.state-accepting{
  fill:none;
  stroke:#22c8d8;
  stroke-width:2;
}

/* Accepting + Active */
.state-accepting.state-active .svg-state{
  fill:rgba(34,200,216,.25);
  filter:drop-shadow(0 0 14px rgba(34,200,216,.55));
}

/* ── Transition: Active (animação de simulação) ───────────────────── */
.transition-active .svg-transition,
.svg-transition.transition-active{
  stroke:var(--accent);
  stroke-width:3;
  filter:drop-shadow(0 0 6px rgba(34,200,216,.5));
}
.transition-active .svg-arrowhead,
.svg-arrowhead.transition-active{
  fill:var(--accent);
}
.transition-active .svg-transition-label,
.svg-transition-label.transition-active{
  fill:#fff;
  font-weight:800;
}

/* ── Turing Machine – Tape Display ────────────────────────────────── */
.tape-display{
  display:flex;
  align-items:center;
  gap:0;
  margin:16px auto;
  padding:6px 12px;
  overflow-x:auto;
  border:1px solid rgba(34,200,216,.15);
  border-radius:10px;
  background:linear-gradient(180deg,rgba(255,255,255,.03),rgba(255,255,255,.01)),#0d1420;
  box-shadow:inset 0 2px 6px rgba(0,0,0,.25);
  scrollbar-width:thin;
  scrollbar-color:rgba(34,200,216,.25) transparent;
}
.tape-cell{
  flex:0 0 auto;
  display:grid;
  place-items:center;
  width:42px;
  height:46px;
  border:1px solid rgba(255,255,255,.1);
  border-right:none;
  background:rgba(255,255,255,.025);
  font-family:ui-monospace,SFMono-Regular,Menlo,Consolas,monospace;
  font-size:1.05rem;
  font-weight:700;
  color:var(--text);
  transition:background .2s ease,border-color .2s ease,color .2s ease;
}
.tape-cell:first-child{border-radius:6px 0 0 6px}
.tape-cell:last-child{border-radius:0 6px 6px 0;border-right:1px solid rgba(255,255,255,.1)}
.tape-cell.blank{color:var(--muted);opacity:.45}
.tape-cell.read{color:rgba(168,180,199,.4);opacity:.6;background:rgba(0,0,0,.15)}


/* Cabeçote (head) – célula atualmente lida */
.tape-cell.head{
  background:rgba(34,200,216,.18);
  border-color:var(--accent);
  color:#fff;
  box-shadow:0 0 12px rgba(34,200,216,.3);
  position:relative;
}
.tape-cell.head::after{
  content:"▼";
  position:absolute;
  top:-18px;
  left:50%;
  transform:translateX(-50%);
  font-size:.7rem;
  color:var(--accent);
  text-shadow:0 0 6px rgba(34,200,216,.5);
}

/* ── Pushdown Automaton – Stack Display ───────────────────────────── */
.stack-display{
  display:flex;
  flex-direction:column;
  align-items:center;
  gap:0;
  min-width:68px;
  max-width:90px;
  margin:0 auto;
  border:1px solid rgba(167,124,255,.2);
  border-radius:8px;
  background:linear-gradient(180deg,rgba(255,255,255,.03),rgba(255,255,255,.01)),#0d1420;
  overflow:hidden;
  box-shadow:inset 0 2px 6px rgba(0,0,0,.25);
}
.stack-label{
  width:100%;
  padding:5px 0;
  text-align:center;
  font-size:.72rem;
  font-weight:700;
  letter-spacing:.06em;
  text-transform:uppercase;
  color:var(--muted);
  background:rgba(255,255,255,.04);
  border-bottom:1px solid rgba(255,255,255,.08);
}
.stack-cell{
  width:100%;
  display:grid;
  place-items:center;
  padding:7px 6px;
  border-bottom:1px solid rgba(255,255,255,.07);
  font-family:ui-monospace,SFMono-Regular,Menlo,Consolas,monospace;
  font-size:1rem;
  font-weight:700;
  color:var(--text);
  transition:background .2s ease;
}
.stack-cell:last-child{border-bottom:none}
.stack-cell.top{
  background:rgba(167,124,255,.15);
  color:#d5c4ff;
  box-shadow:inset 0 0 8px rgba(167,124,255,.12);
}
.stack-cell.bottom-marker{
  color:var(--muted);
  opacity:.5;
  font-size:.9rem;
}

/* ── Derivation Tree ──────────────────────────────────────────────── */
.derivation-tree{
  position:relative;
  min-height:280px;
  display:grid;
  place-items:center;
  border:1px solid rgba(245,165,36,.12);
  border-radius:10px;
  background:
    radial-gradient(ellipse 50% 45% at 50% 30%,rgba(245,165,36,.05),transparent),
    #0b1220;
  overflow:hidden;
  padding:16px;
}
.derivation-tree svg{
  display:block;
  width:100%;
  height:auto;
  max-height:min(55vh,480px);
  min-height:220px;
}
/* Tree node */
.derivation-tree .tree-node{
  fill:#132030;
  stroke:#7a8ea6;
  stroke-width:1.5;
  transition:fill .2s ease,stroke .2s ease;
}
.derivation-tree .tree-node.nonterminal{
  fill:rgba(245,165,36,.1);
  stroke:var(--orange);
}
.derivation-tree .tree-node.terminal{
  fill:rgba(34,200,216,.1);
  stroke:var(--accent);
  rx:4;
  ry:4;
}
.derivation-tree .tree-edge{
  fill:none;
  stroke:#5e718d;
  stroke-width:1.5;
}
.derivation-tree .tree-label{
  font-family:Inter,Arial,sans-serif;
  font-size:12px;
  font-weight:700;
  fill:#eaf2ff;
  text-anchor:middle;
  dominant-baseline:central;
}

/* ── Grammar Display ──────────────────────────────────────────────── */
.grammar-display{
  border:1px solid rgba(79,140,255,.15);
  border-radius:10px;
  background:linear-gradient(180deg,rgba(79,140,255,.04),transparent),#0c111c;
  padding:16px 20px;
  margin:12px 0;
  font-family:ui-monospace,SFMono-Regular,Menlo,Consolas,monospace;
  font-size:.95rem;
  line-height:1.75;
  color:#d5e2f5;
  overflow-x:auto;
}
.grammar-display .production{
  display:flex;
  align-items:baseline;
  gap:6px;
  padding:2px 0;
}
.grammar-display .nonterminal{
  color:var(--orange);
  font-weight:800;
}
.grammar-display .terminal{
  color:var(--accent);
  font-weight:700;
}
.grammar-display .arrow{
  color:var(--muted);
  margin:0 4px;
  user-select:none;
}
.grammar-display .pipe{
  color:var(--muted);
  margin:0 6px;
}
.grammar-display .epsilon{
  color:var(--purple);
  font-style:italic;
}

/* ── Regex Display ────────────────────────────────────────────────── */
.regex-display{
  display:inline-flex;
  align-items:center;
  gap:4px;
  border:1px solid rgba(34,200,216,.18);
  border-radius:8px;
  background:rgba(34,200,216,.06);
  padding:8px 16px;
  margin:8px 0;
  font-family:ui-monospace,SFMono-Regular,Menlo,Consolas,monospace;
  font-size:1.05rem;
  font-weight:600;
  color:var(--text);
  letter-spacing:.02em;
  word-break:break-all;
}
.regex-display .op{
  color:var(--accent);
  font-weight:800;
}
.regex-display .group{
  color:var(--orange);
}
.regex-display .char-class{
  color:var(--purple);
}
.regex-display .quantifier{
  color:var(--red);
  font-weight:800;
}

/* ── Simulation Controls Bar ──────────────────────────────────────── */
.sim-controls{
  display:flex;
  align-items:center;
  gap:8px;
  margin-top:12px;
  padding:8px 12px;
  border:1px solid rgba(255,255,255,.07);
  border-radius:8px;
  background:rgba(255,255,255,.025);
}
.sim-controls .sim-input{
  flex:1;
  min-width:120px;
  border:1px solid rgba(255,255,255,.12);
  border-radius:6px;
  background:rgba(0,0,0,.3);
  color:var(--text);
  font-family:ui-monospace,SFMono-Regular,Menlo,Consolas,monospace;
  font-size:.92rem;
  padding:6px 10px;
  outline:none;
  transition:border-color .2s ease;
}
.sim-controls .sim-input:focus{border-color:var(--accent)}
.sim-controls .sim-input::placeholder{color:rgba(168,180,199,.45)}

.sim-status{
  display:inline-flex;
  align-items:center;
  gap:5px;
  font-size:.85rem;
  font-weight:700;
  padding:4px 10px;
  border-radius:6px;
}
.sim-status.accepted{color:#0c3c2e;background:rgba(29,183,127,.85)}
.sim-status.rejected{color:#3c0c0c;background:rgba(239,75,75,.85)}
.sim-status.running{color:#0c2c3c;background:rgba(34,200,216,.85)}

/* ── Transition Table ─────────────────────────────────────────────── */
.transition-table{
  width:100%;
  border-collapse:collapse;
  margin:12px 0;
  font-size:.9rem;
}
.transition-table th,.transition-table td{
  border:1px solid rgba(255,255,255,.08);
  padding:8px 12px;
  text-align:center;
}
.transition-table th{
  background:rgba(255,255,255,.05);
  color:var(--text);
  font-weight:700;
  font-size:.82rem;
  letter-spacing:.04em;
  text-transform:uppercase;
}
.transition-table td{
  background:rgba(255,255,255,.015);
  color:#d0dcef;
  font-family:ui-monospace,SFMono-Regular,Menlo,Consolas,monospace;
}
.transition-table tr:hover td{background:rgba(34,200,216,.06)}
.transition-table td.active-cell{
  background:rgba(34,200,216,.15);
  color:#fff;
  box-shadow:inset 0 0 0 1px var(--accent);
}

/* ── Glassmorphism Accent Panel ───────────────────────────────────── */
.glass-panel{
  border:1px solid rgba(255,255,255,.1);
  background:rgba(255,255,255,.04);
  backdrop-filter:blur(16px);
  border-radius:12px;
  padding:20px;
  box-shadow:0 8px 32px rgba(0,0,0,.2);
}

/* ── Prova 2 Guide ───────────────────────────────────────────────── */
pre{
  margin:12px 0;
  padding:14px 16px;
  overflow:auto;
  border:1px solid rgba(255,255,255,.08);
  border-radius:8px;
  background:#090e18;
  color:#dff6ff;
  font-family:ui-monospace,SFMono-Regular,Menlo,Consolas,monospace;
  font-size:.92rem;
  line-height:1.55;
}

.p2-overview{
  border-color:rgba(34,200,216,.18);
  background:
    radial-gradient(circle at 16% 0%,rgba(34,200,216,.12),transparent 34%),
    linear-gradient(180deg,rgba(255,255,255,.05),rgba(255,255,255,.015)),
    var(--panel);
}
.p2-overview h2{margin:4px 0 10px}
.p2-pillrow{display:flex;flex-wrap:wrap;gap:8px;margin:16px 0}
.p2-section{scroll-margin-top:92px}
.p2-section + .p2-section{margin-top:16px}
.p2-section h2{margin:6px 0 8px}
.p2-rich-text h3{
  margin:18px 0 8px;
  font-size:1.04rem;
}
.p2-rich-text ul,.p2-rich-text ol{
  color:#d7dfec;
  padding-left:20px;
}
.p2-rich-text li{margin:6px 0}
.p2-topic-link{
  display:inline-flex;
  align-items:center;
  width:max-content;
  max-width:100%;
  margin:6px 0 14px;
  padding:6px 9px;
  border:1px solid rgba(34,200,216,.2);
  border-radius:8px;
  background:rgba(34,200,216,.07);
  color:#dffbff;
  font-size:.86rem;
  font-weight:750;
}
.p2-mini-grid{
  display:grid;
  grid-template-columns:repeat(2,minmax(0,1fr));
  gap:12px;
  margin:14px 0;
}
.p2-mini-grid.three{grid-template-columns:repeat(3,minmax(0,1fr))}
.p2-mini{
  border:1px solid rgba(255,255,255,.08);
  border-radius:8px;
  background:rgba(255,255,255,.035);
  padding:12px;
}
.p2-mini strong{display:block;color:#fff;margin-bottom:4px}
.p2-mini p{font-size:.92rem}
.p2-note{
  margin:14px 0;
  padding:13px 15px;
  border:1px solid rgba(34,200,216,.2);
  border-radius:8px;
  background:rgba(34,200,216,.075);
  color:#dceeff;
}
.p2-note p{margin:0}
.p2-warn{
  border-color:rgba(245,165,36,.32);
  background:rgba(245,165,36,.08);
}
.p2-success{
  border-color:rgba(29,183,127,.32);
  background:rgba(29,183,127,.08);
}
.p2-danger{
  border-color:rgba(239,75,75,.32);
  background:rgba(239,75,75,.08);
}
.p2-table{
  width:100%;
  min-width:640px;
  border-collapse:collapse;
  font-size:.92rem;
}
.p2-table th,.p2-table td{
  border:1px solid rgba(255,255,255,.08);
  padding:10px 12px;
  vertical-align:top;
}
.p2-table th{
  background:rgba(34,200,216,.12);
  color:#fff;
  text-align:left;
  font-weight:800;
}
.p2-table td{
  background:rgba(255,255,255,.018);
  color:#d7dfec;
}
.p2-visuals{margin-top:14px}
.p2-anim{
  display:grid;
  grid-template-columns:minmax(0,1fr);
  gap:12px;
}
.p2-anim-title{
  display:flex;
  align-items:flex-start;
  justify-content:space-between;
  gap:12px;
}
.p2-anim-title h3{margin:0}
.p2-anim-title span{
  color:var(--muted);
  font-size:.88rem;
  text-align:right;
}
.p2-anim button{
  border:1px solid rgba(34,200,216,.34);
  border-radius:8px;
  background:rgba(34,200,216,.12);
  color:#f8fbff;
  cursor:pointer;
  font:800 .88rem/1 Inter,system-ui,sans-serif;
  min-height:38px;
  padding:8px 12px;
}
.p2-anim button:hover:not(:disabled){
  background:var(--accent);
  color:#071111;
}
.p2-anim button:disabled{
  cursor:not-allowed;
  opacity:.45;
}
.p2-anim button.secondary{
  border-color:rgba(255,255,255,.13);
  background:rgba(255,255,255,.06);
}
.p2-anim input{
  width:min(240px,100%);
  border:1px solid rgba(255,255,255,.14);
  border-radius:8px;
  background:#090e18;
  color:var(--text);
  font:800 .94rem/1 ui-monospace,SFMono-Regular,Menlo,Consolas,monospace;
  padding:9px 11px;
  outline:none;
}
.p2-anim input:focus{
  border-color:var(--accent);
  box-shadow:0 0 0 3px rgba(34,200,216,.12);
}
.p2-muted{color:var(--muted)}
.p2-stepbox{
  border:1px solid rgba(255,255,255,.08);
  border-left:3px solid var(--orange);
  border-radius:8px;
  background:rgba(255,255,255,.025);
  color:#dce7f7;
  padding:12px 14px;
}
.p2-bigform{
  display:flex;
  flex-wrap:wrap;
  gap:10px;
  align-items:center;
  margin:10px 0;
  font-family:ui-monospace,SFMono-Regular,Menlo,Consolas,monospace;
  font-size:1.8rem;
  font-weight:850;
}
.p2-symbol{
  display:inline-grid;
  min-width:42px;
  min-height:42px;
  place-items:center;
  border:1px solid rgba(255,255,255,.12);
  border-radius:8px;
  background:rgba(255,255,255,.04);
  color:#eef7ff;
}
.p2-symbol.highlight{
  border-color:rgba(245,165,36,.48);
  background:rgba(245,165,36,.14);
  color:#fff2cc;
}
.p2-symbol.okhilite,.p2-cell.read{
  border-color:rgba(29,183,127,.38);
  background:rgba(29,183,127,.14);
  color:#dffdec;
}
.p2-control-row{
  display:flex;
  flex-wrap:wrap;
  gap:8px;
  align-items:center;
  margin:10px 0;
}
.p2-sim-grid{
  display:grid;
  grid-template-columns:minmax(260px,.78fr) minmax(340px,1fr);
  gap:14px;
  align-items:start;
}
.p2-sim-grid-stack{
  grid-template-columns:minmax(250px,.72fr) minmax(90px,.2fr) minmax(320px,1fr);
}
.p2-sim-panel{
  display:grid;
  gap:10px;
  min-width:0;
}
.p2-tape{
  display:flex;
  align-items:center;
  overflow-x:auto;
  padding:8px 6px;
  border:1px solid rgba(34,200,216,.14);
  border-radius:8px;
  background:#0b1220;
}
.p2-cell{
  position:relative;
  flex:0 0 42px;
  display:grid;
  place-items:center;
  height:44px;
  border:1px solid rgba(255,255,255,.12);
  border-right:none;
  background:rgba(255,255,255,.025);
  color:#e9f4ff;
  font:850 1rem/1 ui-monospace,SFMono-Regular,Menlo,Consolas,monospace;
}
.p2-cell:first-child{border-radius:6px 0 0 6px}
.p2-cell:last-child{border-right:1px solid rgba(255,255,255,.12);border-radius:0 6px 6px 0}
.p2-cell.blank{color:rgba(168,180,199,.55)}
.p2-cell.head{
  border-color:var(--accent);
  background:rgba(34,200,216,.18);
  color:#fff;
  box-shadow:0 0 14px rgba(34,200,216,.18);
}
.p2-cell.head::after{
  content:"▼";
  position:absolute;
  top:-17px;
  color:var(--accent);
  font-size:.7rem;
}
.p2-stack-panel{
  display:grid;
  gap:8px;
  justify-items:center;
  color:#fff;
}
.p2-stack{
  display:flex;
  flex-direction:column-reverse;
  min-width:74px;
  max-width:110px;
  min-height:48px;
  border:1px solid rgba(167,124,255,.22);
  border-radius:8px;
  background:#0b1220;
  overflow:hidden;
}
.p2-stackitem{
  display:grid;
  place-items:center;
  min-height:36px;
  border-top:1px solid rgba(255,255,255,.08);
  color:#e9f4ff;
  font:850 1rem/1 ui-monospace,SFMono-Regular,Menlo,Consolas,monospace;
}
.p2-stackitem.empty{
  color:var(--muted);
  font-size:.82rem;
}
.success-inline{color:#95f5c4}
.p2-tree-box{min-height:330px}
.p2-segmentrow{
  display:flex;
  flex-wrap:wrap;
  gap:8px;
  margin:8px 0;
}
.p2-segment{
  min-width:82px;
  border:1px solid rgba(255,255,255,.1);
  border-radius:8px;
  background:rgba(255,255,255,.04);
  color:#eaf2ff;
  padding:10px 12px;
  text-align:center;
  font:800 .92rem/1.35 ui-monospace,SFMono-Regular,Menlo,Consolas,monospace;
}
.p2-segment.seg-v{border-color:rgba(245,165,36,.38);background:rgba(245,165,36,.1)}
.p2-segment.seg-y{border-color:rgba(167,124,255,.38);background:rgba(167,124,255,.1)}
.p2-segment.seg-x{border-color:rgba(34,200,216,.28);background:rgba(34,200,216,.08)}
.formula-inline{
  color:#dff6ff;
  font-family:ui-monospace,SFMono-Regular,Menlo,Consolas,monospace;
}
.p2-two-grid{
  display:grid;
  grid-template-columns:repeat(2,minmax(0,1fr));
  gap:12px;
  margin-top:8px;
}
.p2-two-grid strong{
  display:block;
  margin-bottom:6px;
  color:#fff;
}
.p2-checklist{
  display:grid;
  grid-template-columns:repeat(2,minmax(0,1fr));
  gap:8px;
  margin:16px 0;
}
.p2-checklist label{
  display:flex;
  gap:9px;
  align-items:flex-start;
  min-height:44px;
  padding:10px 12px;
  border:1px solid rgba(255,255,255,.08);
  border-radius:8px;
  background:rgba(255,255,255,.03);
  color:#dce7f7;
}
.p2-checklist input{
  flex:0 0 auto;
  margin-top:3px;
  accent-color:var(--accent);
}
.p2-related{margin-top:16px}
.p2-related h3{margin-bottom:8px}
.p2-related-grid{
  display:grid;
  grid-template-columns:repeat(auto-fit,minmax(220px,1fr));
  gap:10px;
  margin-top:12px;
}
.p2-related-link{
  display:grid;
  gap:7px;
  border:1px solid rgba(255,255,255,.08);
  border-radius:8px;
  background:rgba(255,255,255,.03);
  padding:12px;
}
.p2-related-link small{
  color:var(--muted);
  line-height:1.35;
}
.multi-tape-container{
  display:grid;
  gap:12px;
  margin-top:12px;
}
.multi-tape-row{
  display:grid;
  gap:6px;
  min-width:0;
}
.multi-tape-row strong{
  color:#fff;
  font-size:.9rem;
}

/* ── Pulse animation (for active states) ──────────────────────────── */
@keyframes pulse-cyan{
  0%,100%{filter:drop-shadow(0 0 6px rgba(34,200,216,.3))}
  50%{filter:drop-shadow(0 0 16px rgba(34,200,216,.6))}
}
.state-active .svg-state,
.svg-state.state-active{
  animation:pulse-cyan 1.6s ease-in-out infinite;
}

@keyframes tape-slide{
  from{transform:translateX(42px);opacity:0}
  to{transform:translateX(0);opacity:1}
}
.tape-cell.entering{animation:tape-slide .25s ease-out}

@keyframes stack-push{
  from{transform:translateY(-20px);opacity:0}
  to{transform:translateY(0);opacity:1}
}
.stack-cell.pushing{animation:stack-push .25s ease-out}

@keyframes stack-pop{
  from{transform:translateY(0);opacity:1}
  to{transform:translateY(-20px);opacity:0}
}
.stack-cell.popping{animation:stack-pop .25s ease-in forwards}

/* ── Responsive ───────────────────────────────────────────────────── */
@media (max-width:920px){
  .hero,.app-layout,.exercise-body{grid-template-columns:1fr}
  .hero{min-height:auto}
  .rail{position:relative;top:0;max-height:none}
  .app-layout.rail-collapsed{grid-template-columns:1fr}
  .rail.is-collapsed{padding:10px 12px}
  .rail.is-collapsed .rail-head{justify-content:space-between}
  .rail.is-collapsed .rail-title{
    width:auto;height:auto;opacity:1;transform:none;
  }
  .topic-grid,.animation-grid,.mini-stats{grid-template-columns:1fr}
  .section-heading{display:block}
  .topbar{position:relative;align-items:flex-start}
  .visual-card,.content-card,.graph-box,.automaton-box{min-width:0}
  .graph-box svg,.automaton-box svg{min-width:0;min-height:260px}
  .p2-anim .graph-box svg{min-height:0}
  .tape-display{margin:12px 0}
  .stack-display{max-width:100%;flex-direction:row;flex-wrap:wrap}
  .sim-controls{flex-wrap:wrap}
  .p2-mini-grid,.p2-mini-grid.three,.p2-checklist{grid-template-columns:1fr}
  .p2-sim-grid,.p2-sim-grid-stack,.p2-two-grid{grid-template-columns:1fr}
  .p2-anim-title{display:block}
  .p2-anim-title span{display:block;margin-top:4px;text-align:left}
  .p2-topic-link{width:100%}
  .p2-table{min-width:560px}
}

/* ── Motion preferences ───────────────────────────────────────────── */
@media (prefers-reduced-motion:no-preference){
  .topic-card,.animation-card,.content-card,.exercise-card{
    transition:transform .18s ease,border-color .18s ease;
  }
  .topic-card:hover,.animation-card:hover,.exercise-card:hover{
    transform:translateY(-2px);
    border-color:rgba(34,200,216,.28);
  }
}
@media (prefers-reduced-motion:reduce){
  .state-active .svg-state,
  .svg-state.state-active{animation:none}
  .tape-cell.entering{animation:none}
  .stack-cell.pushing,.stack-cell.popping{animation:none}
}