/* ════════════════════════════════════════════
   PDA SIMULATOR – STYLE.CSS
   Aesthetic: Dark Sci-Fi Terminal / Presentation
   ════════════════════════════════════════════ */

/* ── Variables ───────────────────────────── */
:root {
  --bg: #090b14;
  --bg2: #0d1120;
  --surface: rgba(255,255,255,.04);
  --surface2: rgba(255,255,255,.08);
  --border: rgba(255,255,255,.10);
  --accent: #00e5ff;
  --accent2: #7c4dff;
  --accent3: #ff6b6b;
  --green: #00e676;
  --yellow: #ffd740;
  --text: #e8eaf0;
  --text2: #8892a4;
  --text3: #4a5568;
  --nav-w: 200px;
  --font-display: 'Orbitron', monospace;
  --font-mono: 'Space Mono', monospace;
  --font-body: 'Inter', sans-serif;
  --radius: 12px;
  --glow: 0 0 20px rgba(0,229,255,.25);
  --glow2: 0 0 20px rgba(124,77,255,.25);
}

/* ── 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(--font-body);
  min-height: 100vh;
  overflow-x: hidden;
}

/* ── Grid background ─────────────────────── */
.grid-bg {
  position: absolute; inset: 0; z-index: 0;
  background-image:
    linear-gradient(rgba(0,229,255,.04) 1px, transparent 1px),
    linear-gradient(90deg, rgba(0,229,255,.04) 1px, transparent 1px);
  background-size: 48px 48px;
  pointer-events: none;
}
.scanline {
  position: absolute; inset: 0; z-index: 0;
  background: repeating-linear-gradient(
    to bottom,
    transparent, transparent 3px,
    rgba(0,0,0,.08) 3px, rgba(0,0,0,.08) 4px
  );
  pointer-events: none;
  animation: scan 8s linear infinite;
}
@keyframes scan {
  0%   { background-position: 0 0; }
  100% { background-position: 0 80px; }
}

/* ── Side Nav ────────────────────────────── */
.sidenav {
  position: fixed; top: 0; left: 0;
  width: var(--nav-w); height: 100vh;
  background: rgba(9,11,20,.95);
  border-right: 1px solid var(--border);
  display: flex; flex-direction: column;
  padding: 24px 0;
  z-index: 100;
  backdrop-filter: blur(12px);
}
.nav-logo {
  font-family: var(--font-display);
  font-size: 1.3rem; font-weight: 900;
  color: var(--text);
  padding: 0 24px 24px;
  letter-spacing: 2px;
  border-bottom: 1px solid var(--border);
  margin-bottom: 16px;
}
.nav-logo span { color: var(--accent); }
.sidenav ul { list-style: none; flex: 1; }
.sidenav ul li { }
.sidenav ul li button {
  width: 100%; text-align: left;
  padding: 12px 24px;
  background: none; border: none;
  color: var(--text2);
  font-family: var(--font-body);
  font-size: .85rem; font-weight: 500;
  cursor: pointer;
  transition: all .2s;
  border-left: 3px solid transparent;
  position: relative;
}
.sidenav ul li button:hover,
.sidenav ul li button.active {
  color: var(--accent);
  border-left-color: var(--accent);
  background: rgba(0,229,255,.06);
}

/* ── Sections ────────────────────────────── */
.section {
  margin-left: var(--nav-w);
  min-height: 100vh;
  position: relative;
  display: flex; align-items: center; justify-content: center;
  padding: 60px 40px;
  overflow: hidden;
}
.section-inner {
  position: relative; z-index: 1;
  width: 100%; max-width: 1000px;
}
.section-header {
  margin-bottom: 48px;
  text-align: center;
}
.section-num {
  font-family: var(--font-display);
  font-size: 4rem; font-weight: 900;
  color: rgba(0,229,255,.08);
  line-height: 1;
  margin-bottom: 4px;
  letter-spacing: 4px;
}
.section-header h2 {
  font-family: var(--font-display);
  font-size: 2rem; font-weight: 700;
  color: var(--text);
  letter-spacing: 1px;
  margin-bottom: 8px;
}
.section-header p { color: var(--text2); font-size: .95rem; }

/* ── HERO ────────────────────────────────── */
#hero { background: radial-gradient(ellipse at 30% 40%, rgba(0,229,255,.06) 0%, transparent 60%),
                   radial-gradient(ellipse at 70% 60%, rgba(124,77,255,.06) 0%, transparent 60%),
                   var(--bg); }
.hero-content {
  position: relative; z-index: 2;
  text-align: center;
  max-width: 700px;
}
.badge {
  display: inline-block;
  background: rgba(0,229,255,.1);
  border: 1px solid rgba(0,229,255,.3);
  color: var(--accent);
  font-size: .75rem; font-weight: 600;
  letter-spacing: 2px; text-transform: uppercase;
  padding: 6px 16px; border-radius: 20px;
  margin-bottom: 24px;
  animation: fadeUp .6s ease both;
}
.hero-title {
  font-family: var(--font-display);
  font-weight: 900; line-height: 1.1;
  margin-bottom: 16px;
}
.title-line {
  display: block; font-size: clamp(3rem, 8vw, 5.5rem);
  color: var(--text);
  animation: fadeUp .6s ease both;
  animation-delay: .1s;
}
.title-line.accent {
  color: var(--accent);
  text-shadow: 0 0 40px rgba(0,229,255,.4);
  animation-delay: .2s;
}
.hero-sub {
  font-family: var(--font-mono);
  color: var(--text2); font-size: .9rem;
  letter-spacing: 1px; margin-bottom: 20px;
  animation: fadeUp .6s ease both .3s;
}
.hero-desc {
  color: var(--text2); font-size: 1rem; line-height: 1.7;
  margin-bottom: 24px;
  animation: fadeUp .6s ease both .35s;
}
.hero-desc strong { color: var(--accent); }
.hero-desc em { color: var(--accent2); font-style: normal; }
.hero-chips {
  display: flex; flex-wrap: wrap; gap: 8px;
  justify-content: center; margin-bottom: 32px;
  animation: fadeUp .6s ease both .4s;
}
.chip {
  padding: 5px 14px; border-radius: 20px;
  border: 1px solid var(--border);
  background: var(--surface);
  font-size: .78rem; color: var(--text2);
  font-weight: 500;
}

/* ── Orbs ────────────────────────────────── */
.orb {
  position: absolute; border-radius: 50%;
  filter: blur(80px); opacity: .4; pointer-events: none;
  animation: float 8s ease-in-out infinite;
}
.orb1 { width: 300px; height: 300px; background: var(--accent2); top: 10%; left: 5%; animation-delay: 0s; }
.orb2 { width: 200px; height: 200px; background: var(--accent); top: 60%; right: 5%; animation-delay: 3s; }
.orb3 { width: 150px; height: 150px; background: #ff6b6b; bottom: 10%; left: 30%; animation-delay: 6s; }
@keyframes float {
  0%,100% { transform: translateY(0) scale(1); }
  50%      { transform: translateY(-24px) scale(1.05); }
}

/* ── Buttons ─────────────────────────────── */
.btn-glow {
  display: inline-flex; align-items: center; gap: 8px;
  padding: 14px 32px; border-radius: 8px;
  background: linear-gradient(135deg, var(--accent), var(--accent2));
  border: none; color: #fff;
  font-family: var(--font-display); font-size: .85rem; font-weight: 700;
  letter-spacing: 1px; cursor: pointer;
  box-shadow: 0 0 24px rgba(0,229,255,.4), 0 4px 20px rgba(0,0,0,.3);
  transition: all .3s;
  animation: fadeUp .6s ease both .5s;
}
.btn-glow:hover {
  transform: translateY(-2px);
  box-shadow: 0 0 40px rgba(0,229,255,.6), 0 8px 30px rgba(0,0,0,.4);
}
.btn-glow:active { transform: translateY(0); }
.btn-outline {
  display: inline-flex; align-items: center; gap: 8px;
  padding: 12px 28px; border-radius: 8px;
  background: transparent;
  border: 1px solid var(--accent); color: var(--accent);
  font-family: var(--font-body); font-size: .9rem; font-weight: 600;
  cursor: pointer; transition: all .3s;
}
.btn-outline:hover {
  background: rgba(0,229,255,.08);
  box-shadow: var(--glow);
}

/* ── Concepts grid ───────────────────────── */
.concepts-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(260px, 1fr));
  gap: 20px; margin-bottom: 40px;
}
.concept-card {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 24px;
  backdrop-filter: blur(8px);
  transition: transform .25s, box-shadow .25s, border-color .25s;
  animation: fadeUp .5s ease both;
  animation-delay: var(--delay, 0s);
}
.concept-card:hover {
  transform: translateY(-4px);
  box-shadow: var(--glow);
  border-color: rgba(0,229,255,.3);
}
.concept-icon {
  font-family: var(--font-display);
  font-size: 1.8rem; font-weight: 900;
  color: var(--accent);
  margin-bottom: 12px;
}
.concept-card h3 { font-size: 1rem; font-weight: 600; margin-bottom: 8px; }
.concept-card p { color: var(--text2); font-size: .85rem; line-height: 1.6; }
.formal-def {
  text-align: center; margin: 32px 0 24px;
  background: var(--surface); border: 1px solid var(--border);
  border-radius: var(--radius); padding: 16px 24px;
}
.mono {
  font-family: var(--font-mono);
  color: var(--accent2); font-size: 1rem;
  letter-spacing: 1px;
}

/* ── Input form ──────────────────────────── */
.sample-row {
  display: flex; align-items: center; gap: 10px;
  margin-bottom: 28px; flex-wrap: wrap;
}
.sample-label { color: var(--text2); font-size: .85rem; font-weight: 600; }
.btn-sample {
  padding: 7px 16px; border-radius: 6px;
  background: var(--surface2); border: 1px solid var(--border);
  color: var(--text); font-size: .82rem; cursor: pointer;
  transition: all .2s; font-family: var(--font-mono);
}
.btn-sample:hover {
  background: rgba(0,229,255,.1); border-color: var(--accent);
  color: var(--accent);
}
.input-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(260px, 1fr));
  gap: 20px; margin-bottom: 20px;
}
.input-group { display: flex; flex-direction: column; gap: 6px; }
.input-group label {
  font-size: .82rem; font-weight: 600;
  color: var(--text2); text-transform: uppercase; letter-spacing: .5px;
}
.input-group .hint {
  font-size: .75rem; color: var(--text3);
  text-transform: none; letter-spacing: 0; font-weight: 400;
}
.input-group input,
.input-group select,
.input-group textarea {
  background: var(--surface2);
  border: 1px solid var(--border);
  border-radius: 8px;
  padding: 10px 14px;
  color: var(--text);
  font-family: var(--font-mono);
  font-size: .85rem;
  transition: border-color .2s, box-shadow .2s;
  resize: vertical;
}
.input-group input:focus,
.input-group select:focus,
.input-group textarea:focus {
  outline: none;
  border-color: var(--accent);
  box-shadow: 0 0 0 2px rgba(0,229,255,.15);
}
.input-group textarea { min-height: 160px; }
.input-group code {
  background: rgba(0,229,255,.1); color: var(--accent);
  padding: 1px 5px; border-radius: 4px;
  font-family: var(--font-mono); font-size: .78rem;
}
.full-width { margin-bottom: 20px; }
.input-row { display: flex; gap: 20px; margin-bottom: 28px; flex-wrap: wrap; }
.input-row .input-group { min-width: 180px; }
.action-row { display: flex; gap: 16px; align-items: center; flex-wrap: wrap; }
select option { background: var(--bg2); }

/* ── Toast ───────────────────────────────── */
.toast {
  margin-top: 20px;
  padding: 14px 20px;
  border-radius: 8px;
  background: rgba(255,107,107,.15);
  border: 1px solid rgba(255,107,107,.4);
  color: #ff8a80;
  font-size: .85rem;
  animation: fadeUp .3s ease;
}
.toast.success {
  background: rgba(0,230,118,.12);
  border-color: rgba(0,230,118,.35);
  color: var(--green);
}
.toast.hidden { display: none; }

/* ── Diagram ─────────────────────────────── */
.diagram-wrap {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 20px;
  min-height: 460px;
  position: relative;
  overflow: hidden;
}
.diagram-hint {
  position: absolute; inset: 0;
  display: flex; align-items: center; justify-content: center;
  color: var(--text3); font-size: .9rem;
}
#pda-diagram { display: block; }

/* SVG styling */
.state-circle {
  fill: var(--surface2);
  stroke: rgba(0,229,255,.4);
  stroke-width: 2;
  transition: fill .3s, stroke .3s;
  cursor: default;
}
.state-circle.active {
  fill: rgba(0,229,255,.2);
  stroke: var(--accent);
  filter: drop-shadow(0 0 8px rgba(0,229,255,.6));
}
.state-circle.accept { stroke-width: 4; stroke: var(--green); }
.state-label {
  fill: var(--text);
  font-family: var(--font-mono);
  font-size: 13px;
  dominant-baseline: central;
  text-anchor: middle;
  pointer-events: none;
}
.trans-arrow { stroke: rgba(0,229,255,.3); stroke-width: 1.5; fill: none; transition: stroke .3s; }
.trans-arrow.active { stroke: var(--accent2); stroke-width: 2.5; filter: drop-shadow(0 0 4px var(--accent2)); }
.trans-label {
  fill: var(--text2); font-size: 10px;
  font-family: var(--font-mono);
  text-anchor: middle;
}
.trans-label.active { fill: var(--accent2); }
.start-arrow { stroke: var(--accent); stroke-width: 2; fill: none; }

/* ── Simulation ──────────────────────────── */
.sim-layout { display: grid; grid-template-columns: 1fr 1fr; gap: 28px; margin-bottom: 36px; }
.sim-controls {
  display: flex; gap: 10px; margin-bottom: 20px; flex-wrap: wrap;
}
.ctrl-btn {
  width: 48px; height: 48px; border-radius: 10px;
  background: var(--surface2); border: 1px solid var(--border);
  color: var(--text); font-size: 1rem;
  cursor: pointer; transition: all .2s;
  display: flex; align-items: center; justify-content: center;
}
.ctrl-btn:hover { background: rgba(0,229,255,.1); border-color: var(--accent); color: var(--accent); }
.ctrl-btn.play.playing { background: rgba(255,107,107,.1); border-color: var(--accent3); color: var(--accent3); }
.ctrl-btn:disabled { opacity: .35; cursor: not-allowed; }
.speed-row {
  display: flex; align-items: center; gap: 10px;
  margin-bottom: 20px; font-size: .8rem; color: var(--text2);
}
.speed-row input[type=range] { flex: 1; accent-color: var(--accent); }
.current-panel { padding: 20px; }
.glass-card {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  backdrop-filter: blur(8px);
}
.cur-row {
  display: flex; justify-content: space-between; align-items: flex-start;
  padding: 10px 0; border-bottom: 1px solid var(--border);
}
.cur-row:last-child { border-bottom: none; }
.cur-label { font-size: .75rem; color: var(--text3); text-transform: uppercase; letter-spacing: .5px; font-weight: 600; }
.cur-val { font-family: var(--font-mono); font-size: .9rem; color: var(--text); text-align: right; max-width: 60%; word-break: break-all; }
.cur-val.small { font-size: .75rem; }
.state-badge {
  background: rgba(0,229,255,.12); color: var(--accent);
  padding: 2px 10px; border-radius: 4px;
  border: 1px solid rgba(0,229,255,.25);
}

/* Tape */
.tape-section, .stack-section { margin-bottom: 20px; }
.tape-section h4, .stack-section h4 { font-size: .8rem; color: var(--text2); text-transform: uppercase; letter-spacing: 1px; margin-bottom: 10px; }
.tape {
  display: flex; flex-wrap: wrap; gap: 4px;
}
.tape-cell {
  width: 38px; height: 38px;
  border: 1px solid var(--border);
  border-radius: 6px;
  background: var(--surface2);
  font-family: var(--font-mono); font-size: .9rem;
  display: flex; align-items: center; justify-content: center;
  position: relative;
  transition: all .3s;
}
.tape-cell.current {
  background: rgba(0,229,255,.15);
  border-color: var(--accent);
  box-shadow: 0 0 12px rgba(0,229,255,.3);
}
.tape-cell.consumed { opacity: .35; }
.tape-pointer {
  position: absolute; bottom: -18px; left: 50%;
  transform: translateX(-50%);
  color: var(--accent); font-size: .7rem;
}
.stack-visual {
  display: flex; gap: 4px; flex-wrap: wrap;
}
.stack-cell {
  padding: 6px 14px;
  border-radius: 6px;
  background: rgba(124,77,255,.15);
  border: 1px solid rgba(124,77,255,.35);
  color: var(--accent2);
  font-family: var(--font-mono); font-size: .9rem;
  animation: popIn .25s ease;
  transition: all .3s;
}
.stack-cell.top {
  background: rgba(0,229,255,.18);
  border-color: var(--accent);
  color: var(--accent);
  box-shadow: 0 0 10px rgba(0,229,255,.3);
}
@keyframes popIn { from { transform: scale(.7); opacity:0; } to { transform: scale(1); opacity:1; } }

/* Timeline */
.timeline-wrap { }
.timeline-wrap h4 { font-size: .8rem; color: var(--text2); text-transform: uppercase; letter-spacing: 1px; margin-bottom: 12px; }
.timeline {
  display: flex; gap: 6px; flex-wrap: wrap;
}
.tl-step {
  width: 34px; height: 34px; border-radius: 50%;
  background: var(--surface2); border: 1px solid var(--border);
  display: flex; align-items: center; justify-content: center;
  font-family: var(--font-mono); font-size: .7rem; color: var(--text2);
  cursor: pointer;
  transition: all .2s;
}
.tl-step:hover { border-color: var(--accent); color: var(--accent); }
.tl-step.active-tl { background: rgba(0,229,255,.18); border-color: var(--accent); color: var(--accent); box-shadow: 0 0 8px rgba(0,229,255,.3); }
.tl-step.dead-tl { background: rgba(255,107,107,.1); border-color: rgba(255,107,107,.3); color: var(--accent3); }

/* ── Result ──────────────────────────────── */
.result-center { display: flex; align-items: center; justify-content: center; }
.result-card {
  max-width: 520px; width: 100%;
  padding: 48px 40px; text-align: center;
}
.result-icon {
  font-family: var(--font-display);
  font-size: 3.5rem; margin-bottom: 16px;
  animation: pulse 2s ease infinite;
}
@keyframes pulse { 0%,100%{transform:scale(1)} 50%{transform:scale(1.08)} }
.result-icon.accepted { color: var(--green); text-shadow: 0 0 30px rgba(0,230,118,.5); }
.result-icon.rejected { color: var(--accent3); text-shadow: 0 0 30px rgba(255,107,107,.5); }
#result-title { font-family: var(--font-display); font-size: 1.8rem; margin-bottom: 12px; }
#result-desc { color: var(--text2); margin-bottom: 28px; line-height: 1.6; }
.result-stats {
  display: grid; grid-template-columns: 1fr 1fr;
  gap: 12px; margin-bottom: 28px;
}
.stat-item {
  background: var(--surface2); border: 1px solid var(--border);
  border-radius: 8px; padding: 12px;
}
.stat-label { font-size: .72rem; color: var(--text3); text-transform: uppercase; letter-spacing: .5px; margin-bottom: 4px; }
.stat-val { font-family: var(--font-mono); color: var(--text); font-size: .95rem; }

/* ── Scroll hint ─────────────────────────── */
.scroll-hint {
  position: fixed; bottom: 24px;
  left: calc(var(--nav-w) + 50% - var(--nav-w)/2);
  transform: translateX(-50%);
  color: var(--text3); animation: bounce 2s ease infinite;
  pointer-events: none; z-index: 50;
}
@keyframes bounce { 0%,100%{transform:translateX(-50%) translateY(0)} 50%{transform:translateX(-50%) translateY(8px)} }

/* ── Animations ──────────────────────────── */
@keyframes fadeUp {
  from { opacity: 0; transform: translateY(20px); }
  to   { opacity: 1; transform: translateY(0); }
}

/* ── Responsive ──────────────────────────── */
@media (max-width: 768px) {
  :root { --nav-w: 0px; }
  .sidenav { display: none; }
  .section { padding: 40px 20px; }
  .sim-layout { grid-template-columns: 1fr; }
  .concepts-grid { grid-template-columns: 1fr; }
}