/* ============ Robotics Lab Interactive — global styles ============ */
:root {
  --bg: #0a0e1a;
  --bg-elev: #121828;
  --bg-card: #161d31;
  --border: #232b44;
  --text: #e7ecf5;
  --text-dim: #9aa4bf;
  --text-mute: #6b7595;
  --accent: #00e5ff;
  --accent-2: #7c4dff;
  --accent-3: #ff4d8d;
  --good: #4ade80;
  --warn: #fbbf24;
  --bad: #f87171;
  --mono: ui-monospace, "JetBrains Mono", "Fira Code", "Cascadia Code", Consolas, monospace;
  --sans: "Inter", system-ui, -apple-system, "Segoe UI", Roboto, sans-serif;
}

* { box-sizing: border-box; }

html, body {
  margin: 0;
  padding: 0;
  background: var(--bg);
  color: var(--text);
  font-family: var(--sans);
  font-size: 16px;
  line-height: 1.55;
  -webkit-font-smoothing: antialiased;
}

body {
  background:
    radial-gradient(ellipse 80% 50% at 50% 0%, rgba(124,77,255,0.15), transparent 60%),
    radial-gradient(ellipse 60% 40% at 100% 100%, rgba(0,229,255,0.08), transparent 60%),
    var(--bg);
  min-height: 100vh;
}

a { color: var(--accent); text-decoration: none; }
a:hover { color: var(--accent-2); }

h1, h2, h3 { letter-spacing: -0.02em; }
h1 { font-size: clamp(2rem, 5vw, 3.5rem); line-height: 1.1; margin: 0 0 1rem; }
h1 em { font-style: normal; background: linear-gradient(90deg, var(--accent), var(--accent-2)); -webkit-background-clip: text; background-clip: text; color: transparent; }
h2 { font-size: clamp(1.5rem, 3vw, 2.25rem); margin: 0 0 0.5rem; }
h3 { font-size: 1.15rem; margin: 0 0 0.4rem; }

/* ============ Header ============ */
.site-header {
  display: flex; align-items: center; justify-content: space-between;
  padding: 1rem 2rem; border-bottom: 1px solid var(--border);
  position: sticky; top: 0; z-index: 50;
  backdrop-filter: blur(12px);
  background: rgba(10,14,26,0.7);
}
.brand { display: inline-flex; align-items: center; gap: 0.6rem; font-weight: 700; color: var(--text); }
.brand .logo { color: var(--accent); font-size: 1.5rem; }
.brand-text em { font-style: normal; color: var(--text-dim); font-weight: 400; }
.site-nav { display: flex; gap: 1.5rem; }
.site-nav a { color: var(--text-dim); font-size: 0.9rem; }
.site-nav a:hover { color: var(--text); }

/* ============ Hero ============ */
.hero {
  display: grid; grid-template-columns: 1.2fr 1fr; gap: 3rem;
  max-width: 1200px; margin: 0 auto; padding: 4rem 2rem 3rem;
  align-items: center;
}
.eyebrow { color: var(--accent); font-family: var(--mono); font-size: 0.8rem; letter-spacing: 0.1em; text-transform: uppercase; margin: 0 0 1rem; }
.lede { font-size: 1.15rem; color: var(--text-dim); max-width: 56ch; margin: 0 0 2rem; }
.cta-row { display: flex; gap: 0.8rem; flex-wrap: wrap; }
.btn {
  display: inline-flex; align-items: center; gap: 0.4rem;
  padding: 0.75rem 1.25rem; border-radius: 8px;
  font-weight: 600; font-size: 0.95rem;
  border: 1px solid transparent;
  transition: transform .15s ease, background .15s ease, border-color .15s ease;
}
.btn:hover { transform: translateY(-1px); }
.btn.primary { background: linear-gradient(135deg, var(--accent), var(--accent-2)); color: #0a0e1a; }
.btn.primary:hover { color: #0a0e1a; }
.btn.ghost { border-color: var(--border); color: var(--text); background: var(--bg-elev); }
.btn.ghost:hover { border-color: var(--accent); color: var(--accent); }
.hero-art svg { width: 100%; max-width: 400px; animation: float 6s ease-in-out infinite; }
@keyframes float { 0%,100% { transform: translateY(0); } 50% { transform: translateY(-12px); } }

/* ============ Modules / Cards ============ */
.module { max-width: 1200px; margin: 0 auto; padding: 3rem 2rem; }
.module-head { margin-bottom: 2rem; }
.module-tag { display: inline-block; font-family: var(--mono); font-size: 0.75rem; color: var(--accent); letter-spacing: 0.1em; text-transform: uppercase; margin-bottom: 0.5rem; }
.module-head p { color: var(--text-dim); max-width: 60ch; margin: 0.4rem 0 0; }

.grid {
  display: grid; gap: 1rem;
  grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
}
.card {
  display: block; padding: 1.5rem;
  background: var(--bg-card); border: 1px solid var(--border);
  border-radius: 12px; color: var(--text);
  transition: transform .15s ease, border-color .15s ease, background .15s ease;
  position: relative; overflow: hidden;
}
.card:hover { transform: translateY(-3px); border-color: var(--accent); color: var(--text); }
.card .ic { font-size: 2rem; display: block; margin-bottom: 0.6rem; }
.card h3 { color: var(--text); }
.card p { color: var(--text-dim); font-size: 0.95rem; margin: 0; }
.card.highlight { border-color: rgba(0,229,255,0.3); }
.card.highlight::after {
  content: ""; position: absolute; inset: 0;
  background: radial-gradient(circle at 100% 0%, rgba(0,229,255,0.08), transparent 50%);
  pointer-events: none;
}

/* ============ Summary section ============ */
.summary { max-width: 1200px; margin: 0 auto; padding: 3rem 2rem 5rem; }
.syllabus {
  display: grid; gap: 0.8rem;
  grid-template-columns: repeat(auto-fit, minmax(140px, 1fr));
  margin: 1.5rem 0;
}
.syllabus > div {
  padding: 1rem; background: var(--bg-card); border: 1px solid var(--border); border-radius: 10px;
}
.syllabus strong { font-size: 1.8rem; display: block; color: var(--accent); font-family: var(--mono); }
.syllabus span { color: var(--text-dim); font-size: 0.85rem; }
.bib { color: var(--text-mute); font-size: 0.9rem; }

/* ============ Footer ============ */
.site-footer { padding: 2rem; border-top: 1px solid var(--border); text-align: center; color: var(--text-mute); font-size: 0.85rem; }

/* ============ Sub-pages ============ */
.page-wrap { max-width: 1200px; margin: 0 auto; padding: 2rem; }
.crumb { color: var(--text-mute); font-size: 0.85rem; margin-bottom: 1rem; }
.crumb a { color: var(--text-dim); }
.crumb a:hover { color: var(--accent); }

.page-head { margin-bottom: 2rem; }
.page-head h1 { font-size: clamp(1.8rem, 4vw, 2.8rem); margin-bottom: 0.5rem; }
.page-head .sub { color: var(--text-dim); font-size: 1.1rem; max-width: 60ch; }

.lab {
  display: grid; gap: 1.5rem;
  grid-template-columns: 1fr;
  margin: 2rem 0;
}
@media (min-width: 900px) {
  .lab.split { grid-template-columns: 1.4fr 1fr; }
}

.viz {
  background: var(--bg-card); border: 1px solid var(--border); border-radius: 12px;
  padding: 1rem; min-height: 400px;
  display: flex; align-items: center; justify-content: center;
  position: relative;
}
.viz canvas { max-width: 100%; display: block; }
.viz svg { max-width: 100%; height: auto; }

.panel {
  background: var(--bg-card); border: 1px solid var(--border); border-radius: 12px;
  padding: 1.5rem;
}
.panel h3 { margin-top: 0; }
.panel + .panel { margin-top: 1rem; }

.control {
  display: grid; grid-template-columns: 110px 1fr 60px; gap: 0.6rem;
  align-items: center; margin: 0.6rem 0;
  font-size: 0.9rem;
}
.control label { color: var(--text-dim); font-family: var(--mono); font-size: 0.85rem; }
.control input[type=range] { width: 100%; accent-color: var(--accent); }
.control .val { font-family: var(--mono); color: var(--accent); text-align: right; font-size: 0.85rem; }

.readouts { display: grid; gap: 0.4rem; font-family: var(--mono); font-size: 0.85rem; }
.readouts div { display: flex; justify-content: space-between; padding: 0.3rem 0; border-bottom: 1px dashed var(--border); }
.readouts div:last-child { border: none; }
.readouts .k { color: var(--text-dim); }
.readouts .v { color: var(--accent); }

.btn-row { display: flex; gap: 0.5rem; flex-wrap: wrap; margin-top: 0.6rem; }
.btn-sm {
  padding: 0.45rem 0.9rem; background: var(--bg-elev); color: var(--text);
  border: 1px solid var(--border); border-radius: 6px; cursor: pointer;
  font-size: 0.85rem; font-family: var(--sans); transition: border-color .15s ease, color .15s ease;
}
.btn-sm:hover { border-color: var(--accent); color: var(--accent); }
.btn-sm.active { border-color: var(--accent); color: var(--accent); background: rgba(0,229,255,0.05); }

.tag { display: inline-block; font-family: var(--mono); font-size: 0.7rem; padding: 0.15rem 0.5rem; border-radius: 4px; background: rgba(0,229,255,0.1); color: var(--accent); margin-right: 0.3rem; }

.callout {
  background: linear-gradient(135deg, rgba(0,229,255,0.06), rgba(124,77,255,0.06));
  border-left: 3px solid var(--accent);
  padding: 1rem 1.2rem; border-radius: 4px; margin: 1.2rem 0;
}
.callout p:last-child { margin-bottom: 0; }
.callout strong { color: var(--accent); }

code, pre { font-family: var(--mono); background: var(--bg-elev); padding: 0.15rem 0.4rem; border-radius: 4px; font-size: 0.9em; }
pre { padding: 1rem; overflow-x: auto; }

/* ============ Timeline ============ */
.timeline {
  position: relative; padding-left: 2rem; margin: 2rem 0;
}
.timeline::before {
  content: ""; position: absolute; left: 0.7rem; top: 0; bottom: 0;
  width: 2px; background: linear-gradient(180deg, var(--accent), var(--accent-2));
}
.tl-item {
  position: relative; margin-bottom: 1.5rem;
  padding: 1rem 1.2rem; background: var(--bg-card); border: 1px solid var(--border); border-radius: 10px;
  cursor: pointer; transition: border-color .15s ease, transform .15s ease;
}
.tl-item::before {
  content: ""; position: absolute; left: -1.6rem; top: 1.3rem;
  width: 12px; height: 12px; border-radius: 50%;
  background: var(--accent); border: 3px solid var(--bg);
  box-shadow: 0 0 0 2px var(--accent);
}
.tl-item:hover { border-color: var(--accent); transform: translateX(4px); }
.tl-item .yr { font-family: var(--mono); color: var(--accent); font-size: 0.85rem; }
.tl-item h3 { margin: 0.2rem 0; }
.tl-item .det { display: none; color: var(--text-dim); margin-top: 0.6rem; font-size: 0.9rem; }
.tl-item.open .det { display: block; }

/* ============ Chat (NLP/Pepper) ============ */
.chat { display: flex; flex-direction: column; height: 480px; }
.chat-log {
  flex: 1; overflow-y: auto; padding: 1rem;
  background: var(--bg); border-radius: 8px; border: 1px solid var(--border);
  font-size: 0.95rem;
}
.chat-log .msg { margin-bottom: 0.8rem; }
.chat-log .msg.user { text-align: right; }
.chat-log .bubble {
  display: inline-block; max-width: 80%; padding: 0.6rem 0.9rem;
  border-radius: 12px; background: var(--bg-elev); color: var(--text);
}
.chat-log .msg.user .bubble { background: linear-gradient(135deg, var(--accent), var(--accent-2)); color: #0a0e1a; }
.chat-log .meta { font-size: 0.75rem; color: var(--text-mute); margin-top: 0.2rem; font-family: var(--mono); }
.chat-input { display: flex; gap: 0.5rem; margin-top: 0.8rem; }
.chat-input input {
  flex: 1; padding: 0.7rem 1rem; border-radius: 8px;
  background: var(--bg-elev); border: 1px solid var(--border); color: var(--text); font-size: 0.95rem;
  font-family: var(--sans);
}
.chat-input input:focus { outline: none; border-color: var(--accent); }
.chat-input button {
  padding: 0.7rem 1.2rem; border-radius: 8px;
  background: linear-gradient(135deg, var(--accent), var(--accent-2)); color: #0a0e1a;
  border: none; font-weight: 600; cursor: pointer;
}

/* ============ GPIO pinout ============ */
.pi-board {
  display: grid; grid-template-columns: 1fr 1fr; gap: 0.3rem;
  background: #1a4d2e; padding: 1.5rem; border-radius: 12px; border: 2px solid #0d3818;
  max-width: 520px; margin: 0 auto;
}
.pin {
  display: flex; align-items: center; gap: 0.4rem; padding: 0.35rem 0.5rem;
  background: var(--bg-card); border-radius: 4px; cursor: pointer; font-size: 0.75rem;
  border: 1px solid transparent; transition: border-color .15s ease;
  font-family: var(--mono);
}
.pin.right { flex-direction: row-reverse; }
.pin:hover { border-color: var(--accent); }
.pin.selected { border-color: var(--accent); background: rgba(0,229,255,0.1); }
.pin .num { width: 1.5rem; text-align: center; color: var(--text-mute); }
.pin .lbl { flex: 1; color: var(--text); }
.pin.power-5v { background: #b91c1c; color: #fff; }
.pin.power-3v3 { background: #d97706; color: #fff; }
.pin.gnd { background: #1f2937; color: #94a3b8; }
.pin.gpio .lbl { color: var(--accent); }

@media (max-width: 700px) {
  .site-header { padding: 0.8rem 1rem; }
  .site-nav { gap: 0.8rem; font-size: 0.85rem; }
  .hero { grid-template-columns: 1fr; padding: 2rem 1rem; }
  .hero-art { display: none; }
  .module { padding: 2rem 1rem; }
  .page-wrap { padding: 1rem; }
  .control { grid-template-columns: 90px 1fr 50px; font-size: 0.8rem; }
}