@import url('https://fonts.googleapis.com/css2?family=Outfit:wght@400;500;600;700;800&family=Space+Grotesk:wght@400;600;700&display=swap');

:root {
    --bg: #0a0f1e;
    --surface: #111827;
    --panel: #1a2235;
    --border: rgba(59,130,246,0.2);
    --primary: #3b82f6;
    --secondary: #10b981;
    --accent: #f59e0b;
    --text: #e2e8f0;
    --muted: #94a3b8;
}

*{ margin:0; padding:0; box-sizing:border-box; }

body {
    font-family: 'Outfit', sans-serif;
    background: var(--bg);
    color: var(--text);
    width: 100%; height: 100%;
    overflow: hidden; margin: 0; padding: 0;
}

body::before {
    content: '';
    position: fixed; inset: 0;
    background:
        radial-gradient(ellipse 55% 45% at 10% 20%, rgba(59,130,246,0.06) 0%, transparent 65%),
        radial-gradient(ellipse 50% 60% at 90% 75%, rgba(16,185,129,0.04) 0%, transparent 65%);
    pointer-events: none; z-index: 0;
}

#phet-stage {
    position: absolute; top: 0; left: 0;
    width: 1280px; height: 720px;
    background: var(--bg);
    overflow: hidden; transform-origin: 0 0;
    box-shadow: 0 0 50px rgba(0, 0, 0, 0.4);
    touch-action: none;
    display: flex; flex-direction: column;
}

/* NAV */
.sim-nav{
    display:flex; align-items:center; justify-content:space-between;
    padding:.75rem 2rem;
    background:rgba(17,24,39,0.97);
    border-bottom:1px solid var(--border);
    z-index:100;
    height: 60px;
    flex-shrink: 0;
}
.nav-left{ display:flex; align-items:center; gap:1.5rem; }
.sim-logo{ display:flex; align-items:center; gap:.6rem; font-size:1.1rem; font-weight:700; color:#fff; }
.logo-thin{ font-weight:300; }
.nav-crumbs{ display:flex; align-items:center; gap:.5rem; font-size:.82rem; color:var(--muted); }
.nav-crumbs a{ color:var(--muted); text-decoration:none; transition:color .2s; }
.nav-crumbs a:hover{ color:var(--primary); }
.nav-back{
    display:flex; align-items:center; gap:.5rem;
    padding:.4rem .9rem; border-radius:8px;
    background:rgba(59,130,246,.1); color:var(--primary);
    text-decoration:none; font-size:.82rem; font-weight:600;
    border:1px solid var(--border); transition:all .2s;
}
.nav-back:hover{ background:rgba(59,130,246,.2); }

/* LAYOUT */
.sim-wrap{
    display:grid; grid-template-columns:300px 1fr 340px;
    height: 660px;
    overflow:hidden;
    flex-grow: 1;
}

/* CONTROLS (Left) */
.sim-ctrl{
    background:var(--surface); border-right:1px solid var(--border);
    padding:1.4rem; overflow-y:auto; display:flex;
    flex-direction:column; gap:1.2rem;
    height: 100%;
}
.ctrl-group{ display:flex; flex-direction:column; gap:.6rem; }
.ctrl-title{
    font-size:.7rem; font-weight:700; text-transform:uppercase;
    letter-spacing:1px; color:var(--muted);
    border-bottom:1px solid var(--border); padding-bottom:.4rem;
    display:flex; align-items:center; gap:.4rem;
}

.reaction-card {
    background: #040c1a;
    border: 1px solid var(--border);
    padding: 1rem;
    border-radius: 8px;
    text-align: center;
}
.rxn-title { font-size: 0.75rem; color: var(--muted); margin-bottom: 0.5rem; text-transform: uppercase; font-weight: 600; }
.rxn-eq { font-family: 'Space Grotesk', monospace; font-size: 0.95rem; color: #fff; font-weight: 600; }
.rxn-eq span { color: var(--muted); font-size: 0.75rem; }

label { font-size: 0.8rem; font-weight: 600; color: var(--text); }
.readout-box {
    background: #040c1a;
    border: 1px solid var(--border);
    padding: 0.8rem;
    border-radius: 8px;
}
.r-val { font-family: 'Space Grotesk', monospace; font-size: 1.4rem; font-weight: 700; color: var(--primary); }
.r-unit { font-size: 0.8rem; font-family: 'Outfit'; color: var(--muted); }
.r-lbl { font-size: 0.75rem; color: var(--muted); margin-top: 0.2rem; }

.btn-primary{
    width:100%; padding:.7rem; border-radius:8px;
    background:rgba(59,130,246,0.1); color:var(--primary); 
    border: 1px solid rgba(59,130,246,0.3);
    font-family:'Outfit',sans-serif; font-size:.9rem;
    font-weight:600; cursor:pointer; transition:all .2s;
}
.btn-primary:hover{ background:rgba(59,130,246,0.2); transform:translateY(-1px); }

/* STAGE */
.sim-stage{
    background:#040c1a;
    background-image:radial-gradient(rgba(59,130,246,.08) 1px, transparent 1px);
    background-size:30px 30px;
    position:relative; overflow:hidden;
    height: 100%;
}
#simCanvas{
    max-width:100%; max-height:100%;
}

.instr-badge{
    position:absolute; top:20px; left:50%; transform:translateX(-50%);
    background:rgba(17,24,39,0.8); border:1px solid var(--border);
    padding:0.6rem 1.2rem; border-radius:30px; font-size:0.9rem;
    font-weight:600; color:var(--primary); backdrop-filter:blur(8px);
    pointer-events:none; box-shadow: 0 4px 12px rgba(0,0,0,0.3);
    transition: opacity 0.3s;
}

/* UI OVERLAYS for Stopcock */
.valve-container {
    position: absolute;
    width: 60px;
    height: 60px;
    transform: translate(-50%, -50%);
    cursor: grab;
    z-index: 10;
}
.valve-container:active { cursor: grabbing; }

/* READOUTS (Right) */
.sim-info{
    background:var(--surface); border-left:1px solid var(--border);
    padding:1.4rem; 
    display:flex; flex-direction:column; gap:1.2rem;
    height: 100%;
    overflow-y: auto;
    overflow-x: hidden;
    scrollbar-width: thin;
    scrollbar-color: rgba(59,130,246,0.3) transparent;
}

/* Custom Scrollbar for Right Panel */
.sim-info::-webkit-scrollbar {
    width: 4px;
}
.sim-info::-webkit-scrollbar-track {
    background: transparent;
}
.sim-info::-webkit-scrollbar-thumb {
    background: rgba(59,130,246,0.25);
    border-radius: 10px;
}
.sim-info::-webkit-scrollbar-thumb:hover {
    background: var(--primary);
}

.rd-group {
    display: flex;
    flex-direction: column;
    gap: 1rem;
    flex-shrink: 0;
}
.rd-box{
    background: linear-gradient(145deg, rgba(4,12,26,0.8), rgba(17,24,39,0.9)); 
    border:1px solid rgba(59,130,246,0.25);
    border-radius:12px; padding:1.2rem;
    box-shadow: 0 4px 15px rgba(0,0,0,0.3), inset 0 2px 5px rgba(255,255,255,0.03);
    position: relative; overflow: hidden;
}
.rd-box::before {
    content: ''; position: absolute; top:0; left:0; width:100%; height:2px;
    background: linear-gradient(90deg, transparent, var(--primary), transparent);
    opacity: 0.6;
}
.rd-box:nth-child(2)::before {
    background: linear-gradient(90deg, transparent, #ec4899, transparent);
}
.rd-lbl{ 
    font-size:.65rem; color:var(--muted); font-weight:800; 
    text-transform:uppercase; letter-spacing:1px; margin-bottom:.5rem; 
    display:flex; align-items:center; gap:0.4rem;
}
.rd-lbl i { color: var(--primary); opacity: 0.8; }
.rd-val{ 
    font-family:'Space Grotesk',monospace; font-size:1.8rem; 
    font-weight:700; color:var(--text); line-height:1.1;
    display: flex; align-items: baseline; gap: 0.3rem;
}
.rd-unit { font-size: 0.85rem; color: var(--muted); font-family: 'Outfit'; font-weight: 500; }

.graph-container {
    background: linear-gradient(to bottom, #040c1a, #0b1120); 
    border:1px solid var(--border);
    border-radius:12px; padding:1rem; min-height: 240px;
    display:flex; flex-direction:column;
    position: relative; box-shadow: 0 4px 12px rgba(0,0,0,0.4);
    margin-top: auto;
}
#graphCanvas {
    width: 100%; height: 100%;
    margin-top: 10px; flex-grow: 1;
    display: block;
}