/* ===== Reset & Base ===== */
*,*::before,*::after{margin:0;padding:0;box-sizing:border-box}
:root{
  --clr-primary:#1a2744;
  --clr-accent:#00b4d8;
  --clr-accent2:#ff6b35;
  --clr-bg:#f0f4f8;
  --clr-card:#fff;
  --clr-text:#333;
  --clr-muted:#6c757d;
  --radius:12px;
  --shadow:0 4px 20px rgba(0,0,0,.08);
  --evt-speed:#00b4d8;
  --evt-maneuver:#f77f00;
  --evt-sumo:#e63946;
}
html{scroll-behavior:smooth}
body{font-family:'Segoe UI',Tahoma,Geneva,Verdana,sans-serif;line-height:1.65;color:var(--clr-text);background:var(--clr-bg)}

/* ===== Utility ===== */
.container{max-width:1200px;margin:0 auto;padding:0 20px}
.ico{display:inline-block;margin-right:4px}
code{background:#eef2f6;padding:1px 6px;border-radius:4px;font-size:.92em;font-family:'SF Mono',Menlo,Consolas,monospace}

/* ===== Navigation ===== */
.site-nav{background:var(--clr-primary);padding:12px 0;position:sticky;top:0;z-index:100;box-shadow:0 2px 10px rgba(0,0,0,.15)}
.site-nav .container{display:flex;align-items:center;justify-content:space-between;flex-wrap:wrap;gap:10px}
.site-nav .logo{color:#fff;font-size:1.3rem;font-weight:700;text-decoration:none;display:flex;align-items:center;gap:8px}
.site-nav .logo span{font-size:1.5rem}
.nav-links{list-style:none;display:flex;gap:6px;flex-wrap:wrap}
.nav-links a{color:rgba(255,255,255,.85);text-decoration:none;padding:6px 14px;border-radius:8px;font-size:.9rem;transition:all .2s}
.nav-links a:hover,.nav-links a.active{background:rgba(255,255,255,.15);color:#fff}

/* ===== Hero ===== */
.hero{background:linear-gradient(135deg,var(--clr-primary) 0%,#0d1b2a 100%);color:#fff;padding:70px 20px;text-align:center}
.hero h1{font-size:2.8rem;margin-bottom:10px;letter-spacing:.5px}
.hero .tagline{font-size:1.2rem;opacity:.9;max-width:720px;margin:0 auto 24px}
.hero-badges{display:flex;gap:10px;justify-content:center;flex-wrap:wrap}
.hero-badges .badge{background:rgba(255,255,255,.12);border:1px solid rgba(255,255,255,.22);padding:8px 18px;border-radius:30px;font-size:.92rem;display:inline-flex;align-items:center;gap:6px}

/* ===== Section ===== */
section{padding:55px 0}
section h2{font-size:1.9rem;margin-bottom:8px;color:var(--clr-primary)}
section .section-sub{color:var(--clr-muted);margin-bottom:30px;font-size:1.05rem;max-width:900px}

/* ===== Info grid (re-usable) ===== */
.info-grid{display:grid;grid-template-columns:repeat(auto-fit,minmax(300px,1fr));gap:24px}
.info-box{background:var(--clr-card);border-radius:var(--radius);padding:24px;box-shadow:var(--shadow)}
.info-box h3{font-size:1.12rem;margin-bottom:12px;display:flex;align-items:center;gap:8px;color:var(--clr-primary)}
.info-box ul{list-style:disc inside;color:var(--clr-text)}
.info-box ul li{padding:3px 0;font-size:.94rem}
.info-box p{font-size:.94rem;margin-bottom:10px}

/* ===== Event cards ===== */
.event-grid{display:grid;grid-template-columns:repeat(auto-fit,minmax(320px,1fr));gap:24px}
.event-card{background:var(--clr-card);border-radius:var(--radius);overflow:hidden;box-shadow:var(--shadow);display:flex;flex-direction:column;transition:transform .2s,box-shadow .2s}
.event-card:hover{transform:translateY(-4px);box-shadow:0 8px 30px rgba(0,0,0,.12)}
.event-head{padding:24px;color:#fff;text-align:center}
.event-head .event-icon{font-size:2.6rem;display:block;margin-bottom:6px}
.event-head h3{font-size:1.4rem;margin-bottom:6px}
.event-head p{opacity:.92;font-size:.95rem}
.event-body{padding:20px 24px 24px;flex:1}
.event-body h4{font-size:.95rem;color:var(--clr-primary);margin:14px 0 6px;text-transform:uppercase;letter-spacing:.6px}
.event-body h4:first-child{margin-top:0}
.event-body ul{list-style:disc inside;color:var(--clr-text)}
.event-body ul li{padding:2px 0;font-size:.92rem}

.event-card[data-event="speed"] .event-head{background:linear-gradient(135deg,var(--evt-speed),#0077b6)}
.event-card[data-event="maneuver"] .event-head{background:linear-gradient(135deg,var(--evt-maneuver),#d35400)}
.event-card[data-event="sumo"] .event-head{background:linear-gradient(135deg,var(--evt-sumo),#9d0208)}

/* ===== Diagram cards ===== */
.diagram-card{background:var(--clr-card);border-radius:var(--radius);padding:24px;box-shadow:var(--shadow);margin-bottom:24px}
.diagram-card h3{color:var(--clr-primary);margin-bottom:14px;font-size:1.1rem}
.ascii-diagram{font-family:'SF Mono',Menlo,Consolas,monospace;font-size:.78rem;line-height:1.35;background:#0d1b2a;color:#caf0f8;padding:18px;border-radius:8px;overflow-x:auto;white-space:pre}
.ascii-diagram.small{font-size:.72rem}

/* ===== Wiring section ===== */
.wiring-grid{display:grid;grid-template-columns:repeat(auto-fit,minmax(340px,1fr));gap:24px}
.pin-table{width:100%;border-collapse:collapse;margin-bottom:10px}
.pin-table th,.pin-table td{padding:8px 12px;text-align:left;border-bottom:1px solid #e0e6ec;font-size:.94rem}
.pin-table thead th{background:var(--clr-primary);color:#fff;font-weight:600}
.pin-table tbody tr:hover{background:#f5f9fc}
.hint{font-size:.88rem;color:var(--clr-muted);font-style:italic;margin-top:4px}

/* ===== Code stages ===== */
.stage-list{display:flex;flex-direction:column;gap:24px}
.stage{background:var(--clr-card);border-radius:var(--radius);padding:24px;box-shadow:var(--shadow);border-left:5px solid var(--clr-accent)}
.stage-head{display:flex;align-items:center;gap:14px;margin-bottom:10px}
.stage-num{display:inline-flex;align-items:center;justify-content:center;width:38px;height:38px;border-radius:50%;background:var(--clr-accent);color:#fff;font-weight:700;font-size:1.1rem;flex-shrink:0}
.stage-head h3{color:var(--clr-primary);font-size:1.25rem}
.stage-goal,.stage-concept{font-size:.95rem;margin-bottom:6px}

.code-tabs{display:flex;gap:6px;margin:14px 0 0;flex-wrap:wrap;border-bottom:2px solid #e0e6ec}
.tab-btn{background:none;border:none;padding:10px 16px;font-size:.88rem;font-weight:600;cursor:pointer;color:var(--clr-muted);border-bottom:3px solid transparent;margin-bottom:-2px;transition:all .15s;font-family:inherit}
.tab-btn:hover{color:var(--clr-primary)}
.tab-btn.active{color:var(--clr-primary);border-bottom-color:var(--clr-accent)}

.code-panel{display:none;background:#0d1b2a;color:#e0fbfc;padding:18px;border-radius:8px;margin-top:14px;overflow-x:auto;font-family:'SF Mono',Menlo,Consolas,monospace;font-size:.86rem;line-height:1.55;white-space:pre}
.code-panel.active{display:block}
.code-panel code{background:none;padding:0;color:inherit;font-size:inherit}

.ext-list{list-style:none;margin-top:10px}
.ext-list li{padding:6px 0;padding-left:24px;position:relative;font-size:.94rem}
.ext-list li::before{content:'+';position:absolute;left:0;top:6px;width:18px;height:18px;border-radius:50%;background:var(--clr-accent);color:#fff;font-weight:700;font-size:.8rem;text-align:center;line-height:18px}

/* ===== Safety ===== */
.safety-grid{display:grid;grid-template-columns:repeat(auto-fit,minmax(260px,1fr));gap:18px}
.safety-item{background:var(--clr-card);border-radius:var(--radius);padding:20px;box-shadow:var(--shadow);border-top:3px solid var(--clr-accent2)}
.safety-item h4{color:var(--clr-primary);margin-bottom:6px;font-size:1rem;display:flex;align-items:center;gap:6px}
.safety-item p{font-size:.9rem;color:var(--clr-text)}

/* ===== Footer ===== */
footer{background:var(--clr-primary);color:rgba(255,255,255,.85);text-align:center;padding:24px 20px;font-size:.9rem}
footer a{color:#fff;text-decoration:none}
footer a:hover{text-decoration:underline}

/* ===== Responsive ===== */
@media (max-width:700px){
  .hero h1{font-size:2rem}
  .hero .tagline{font-size:1rem}
  section h2{font-size:1.5rem}
  .ascii-diagram{font-size:.62rem}
  .ascii-diagram.small{font-size:.58rem}
  .nav-links{gap:2px}
  .nav-links a{padding:5px 8px;font-size:.82rem}
}