@import url('https://fonts.googleapis.com/css2?family=JetBrains+Mono:wght@400;700&display=swap');

/* ── ROOT ──────────────────────────────────────────────── */
:root {
    --bg: #030f0a;
    --panel: rgba(5, 20, 12, 0.9);
    --border: rgba(255,255,255,0.07);
    --accent: #10b981;
    --accent-lt: #34d399;
    --accent-glow: rgba(16,185,129,0.15);
    --teal: #06b6d4;
    --amber: #f59e0b;
    --purple: #a855f7;
    --red: #f87171;
    --blue: #3b82f6;
    --text: #f1f5f9;
    --muted: #64748b;
}
* { box-sizing:border-box; margin:0; padding:0; }

body.vsepr-page {
    font-family:'Outfit', sans-serif;
    background:var(--bg); color:var(--text);
    overflow: hidden;
    margin: 0;
    padding: 0;
}

#phet-stage {
    position: absolute;
    top: 0;
    left: 0;
    width: 1280px;
    height: 720px;
    display: flex;
    flex-direction: column;
    overflow: hidden;
    background: var(--bg);
    transform-origin: top left;
}

#phet-stage::before {
    content:''; position:absolute; inset:0;
    background:
        radial-gradient(ellipse 60% 50% at 15% 25%, rgba(16,185,129,0.07) 0%, transparent 65%),
        radial-gradient(ellipse 50% 60% at 85% 70%, rgba(168,85,247,0.05) 0%, transparent 65%);
    pointer-events:none; z-index:0;
}

/* ── NAV ────────────────────────────────────────────────── */
.vsepr-nav {
    position: relative !important;
    display:flex; align-items:center; justify-content:space-between;
    padding:0.6rem 2rem;
    background:rgba(3,15,10,0.92); backdrop-filter:blur(16px);
    border-bottom:1px solid var(--border);
    z-index:300;
}
.vsepr-nav .logo { font-size:1rem; font-weight:800; }
.nav-crumb { font-size:0.78rem; color:#94a3b8; display:flex; align-items:center; gap:0.5rem; }
.nav-crumb strong { color:var(--text); }
.crumb-sep { opacity:0.25; }
.nav-right { display:flex; gap:0.6rem; align-items:center; }
.learn-nav-btn {
    background:rgba(16,185,129,0.12); border:1px solid rgba(16,185,129,0.3);
    color:var(--accent); padding:0.32rem 0.9rem; border-radius:50px;
    font-size:0.78rem; font-weight:700; cursor:pointer;
    display:flex; align-items:center; gap:0.4rem; transition:0.2s; font-family:inherit;
}
.learn-nav-btn:hover { background:var(--accent); color:#030f0a; }
.back-btn {
    border-radius:50px; padding:0.32rem 0.9rem; font-size:0.78rem;
    color:#94a3b8; border:1px solid rgba(255,255,255,0.1);
    text-decoration:none; display:flex; align-items:center; gap:0.4rem; transition:0.2s;
}
.back-btn:hover { border-color:var(--accent); color:var(--accent); }

/* ── MAIN ───────────────────────────────────────────────── */
.vsepr-main {
    flex: 1;
    width: 100%;
    max-width: 1240px;
    margin: 0 auto;
    padding: 0.5rem 1rem 1rem;
    display: flex;
    flex-direction: column;
    gap: 0.65rem;
    position: relative;
    z-index: 1;
    overflow: hidden;
}

/* ── TOP BAR ────────────────────────────────────────────── */
.top-bar {
    background:linear-gradient(135deg, rgba(5,20,12,0.95), rgba(16,185,129,0.05));
    border:1px solid rgba(16,185,129,0.18); border-radius:14px;
    padding:0.65rem 1.1rem;
}
.top-row { display:flex; align-items:center; gap:0.65rem; flex-wrap:wrap; }
.lbl {
    font-size:0.68rem; font-weight:700; color:var(--muted);
    text-transform:uppercase; letter-spacing:0.5px; flex-shrink:0;
}
.mol-pills { display:flex; gap:0.35rem; flex-wrap:wrap; }
.mol-pill {
    background:rgba(255,255,255,0.04); border:1px solid var(--border);
    color:var(--muted); padding:0.26rem 0.75rem; border-radius:30px;
    font-size:0.7rem; font-weight:700; cursor:pointer; transition:0.2s; font-family:inherit;
}
.mol-pill:hover { border-color:var(--accent); color:var(--accent); }
.mol-pill.active {
    background:rgba(16,185,129,0.15); border-color:var(--accent); color:var(--accent);
}

/* ── LAYOUT ─────────────────────────────────────────────── */
.vsepr-layout {
    display:grid; grid-template-columns:230px 1fr 240px;
    gap:0.8rem; align-items:start;
    flex: 1;
    overflow: hidden;
}

/* ── PANEL BOX ───────────────────────────────────────────── */
.panel-box {
    background:var(--panel); border:1px solid var(--border);
    border-radius:13px; padding:0.8rem 0.9rem;
    backdrop-filter:blur(12px); margin-bottom:0.55rem;
}
.panel-title {
    font-size:0.7rem; font-weight:800; text-transform:uppercase;
    letter-spacing:0.7px; color:var(--muted);
    display:flex; align-items:center; gap:0.4rem; margin-bottom:0.55rem;
}

/* ── LEFT PANEL ─────────────────────────────────────────── */
.left-panel { display:flex; flex-direction:column; }

/* Hybridization badge */
.hyb-badge-card {
    background: linear-gradient(135deg, rgba(16,185,129,0.15), rgba(16,185,129,0.05));
    border:1px solid rgba(16,185,129,0.35); border-radius:14px;
    padding: 1rem; text-align:center; margin-bottom:0.55rem;
    position:relative; overflow:hidden;
}
.hyb-badge-card::before {
    content:''; position:absolute; inset:0;
    background: radial-gradient(circle at 50% 50%, rgba(16,185,129,0.1), transparent 70%);
    pointer-events:none;
}
.hyb-label {
    font-size:0.65rem; font-weight:700; text-transform:uppercase; letter-spacing:1px;
    color:var(--muted); margin-bottom:0.35rem;
}
.hyb-value {
    font-size:2.4rem; font-weight:800; color:var(--accent);
    font-family:'JetBrains Mono', monospace; line-height:1;
    text-shadow: 0 0 30px rgba(16,185,129,0.5);
    margin-bottom:0.3rem;
}
.hyb-sub { font-size:0.72rem; color:#94a3b8; }

/* VSEPR notation */
.vsepr-notation {
    font-family:'JetBrains Mono', monospace;
    font-size:1.5rem; font-weight:700; color:var(--teal);
    margin-bottom:0.5rem; text-align:center;
    letter-spacing:2px;
}
.vsepr-legend { display:flex; gap:0.5rem; flex-wrap:wrap; justify-content:center; }
.leg-item { display:flex; align-items:center; gap:0.28rem; font-size:0.62rem; color:var(--muted); }
.leg-dot {
    width:16px; height:16px; border-radius:4px;
    display:flex; align-items:center; justify-content:center;
    font-size:0.6rem; font-weight:800;
}
.leg-dot.a { background:rgba(16,185,129,0.15); color:var(--accent); border:1px solid rgba(16,185,129,0.3); }
.leg-dot.x { background:rgba(6,182,212,0.15); color:var(--teal); border:1px solid rgba(6,182,212,0.3); }
.leg-dot.e { background:rgba(168,85,247,0.15); color:var(--purple); border:1px solid rgba(168,85,247,0.3); }

/* Pairs grid */
.pairs-grid { display:flex; flex-direction:column; gap:0.35rem; }
.pair-item {
    display:flex; align-items:center; justify-content:space-between;
    font-size:0.75rem; padding:0.3rem 0.5rem;
    border-radius:8px; background:rgba(255,255,255,0.02);
    border:1px solid rgba(255,255,255,0.05);
}
.pair-lbl { color:var(--muted); font-size:0.68rem; }
.pair-val { font-weight:700; font-family:'JetBrains Mono',monospace; }
.pair-val.bond { color:var(--teal); }
.pair-val.lone { color:var(--purple); }
.pair-val.total { color:var(--accent); }

/* Bond angle */
.angle-display {
    display:flex; flex-direction:column; align-items:center;
    gap:0.2rem; margin-bottom:0.4rem;
}
.angle-val {
    font-size:2rem; font-weight:800; color:var(--amber);
    font-family:'JetBrains Mono', monospace;
}
.angle-lbl { font-size:0.62rem; color:var(--muted); text-transform:uppercase; letter-spacing:0.5px; }
.angle-note { font-size:0.68rem; color:#94a3b8; line-height:1.55; text-align:center; }

/* ── CENTER PANEL ────────────────────────────────────────── */
.center-panel { display:flex; flex-direction:column; }
.canvas-header {
    display:flex; align-items:center; justify-content:space-between;
    margin-bottom:0.5rem;
}
.canvas-title { font-size:1.1rem; font-weight:800; color:var(--text); }
.shape-tag {
    background:rgba(16,185,129,0.12); border:1px solid rgba(16,185,129,0.3);
    color:var(--accent); padding:0.2rem 0.7rem; border-radius:20px;
    font-size:0.72rem; font-weight:700;
}

.canvas-wrap {
    background:rgba(2,8,5,0.8); border:1px solid rgba(16,185,129,0.12);
    border-radius:16px; overflow:hidden; position:relative;
    cursor:grab; user-select:none;
}
.canvas-wrap:active { cursor:grabbing; }
#vsepr-canvas { display:block; width:100%; height:auto; }
.canvas-hint {
    position:absolute; bottom:0.6rem; right:0.8rem;
    font-size:0.6rem; color:rgba(255,255,255,0.2);
    text-transform:uppercase; letter-spacing:0.5px;
    pointer-events:none;
}

/* Fact bar */
.fact-bar {
    background:linear-gradient(135deg, rgba(5,20,12,0.92), rgba(16,185,129,0.06));
    border:1px solid rgba(16,185,129,0.2); border-radius:12px;
    padding:0.6rem 1rem; display:flex; align-items:center; gap:0.7rem;
    margin-top:0.5rem;
}
.fact-icon { font-size:1.3rem; flex-shrink:0; }
.fact-text { font-size:0.75rem; color:#94a3b8; line-height:1.55; }
.fact-text strong { color:var(--accent); }

/* Controls */
.controls-row {
    display:flex; gap:0.5rem; flex-wrap:wrap; margin-top:0.5rem;
    justify-content:center;
}
.ctrl-btn {
    background:rgba(255,255,255,0.04); border:1px solid var(--border);
    color:var(--muted); padding:0.35rem 0.85rem; border-radius:8px;
    font-size:0.72rem; font-weight:700; cursor:pointer;
    transition:0.2s; font-family:inherit;
    display:flex; align-items:center; gap:0.4rem;
}
.ctrl-btn.active {
    background:rgba(16,185,129,0.12); border-color:rgba(16,185,129,0.35); color:var(--accent);
}
.ctrl-btn:hover { border-color:var(--accent); color:var(--accent); }

/* ── RIGHT PANEL ─────────────────────────────────────────── */
.right-panel { display:flex; flex-direction:column; }

/* Shape gallery */
.shape-gallery { display:flex; flex-direction:column; gap:0.35rem; }
.shape-item {
    display:flex; align-items:center; gap:0.6rem;
    padding:0.4rem 0.55rem; border-radius:9px;
    border:1px solid var(--border);
    cursor:pointer; transition:0.2s;
    background:rgba(255,255,255,0.02);
}
.shape-item:hover { border-color:rgba(16,185,129,0.3); background:rgba(16,185,129,0.05); }
.shape-item.active {
    border-color:rgba(16,185,129,0.4); background:rgba(16,185,129,0.08);
}
.shape-emoji { font-size:1.2rem; flex-shrink:0; }
.shape-info { flex:1; min-width:0; }
.shape-name { font-size:0.72rem; font-weight:700; color:var(--text); }
.shape-formula { font-size:0.6rem; color:var(--muted); font-family:'JetBrains Mono',monospace; }

/* Hybridization steps */
.hyb-steps { display:flex; flex-direction:column; gap:0.45rem; }
.hs-item {
    display:flex; gap:0.55rem; align-items:flex-start;
    font-size:0.72rem; color:#94a3b8; line-height:1.6;
}
.hs-num {
    background:rgba(16,185,129,0.12); color:var(--accent);
    border-radius:6px; padding:0.1rem 0.35rem;
    font-size:0.62rem; font-weight:800; flex-shrink:0; font-family:'JetBrains Mono',monospace;
    margin-top:2px;
}
.hs-text strong { color:var(--text); }
.hs-text em { color:var(--teal); font-style:normal; font-weight:700; }

/* ── MODAL ───────────────────────────────────────────────── */
.modal-overlay {
    position:fixed; inset:0; background:rgba(3,15,10,0.9);
    backdrop-filter:blur(12px); z-index:1000;
    display:flex; align-items:center; justify-content:center;
    padding:1rem; animation:mfade 0.2s ease;
}
.modal-overlay.hidden { display:none; }
@keyframes mfade { from{opacity:0}to{opacity:1} }
.modal-box {
    background:linear-gradient(145deg,#051409,#030d07);
    border:1px solid rgba(16,185,129,0.2); border-radius:22px;
    padding:1.4rem; width:100%; max-width:620px; max-height:88vh;
    overflow-y:auto; position:relative;
    box-shadow:0 35px 90px rgba(0,0,0,0.7);
    animation:mslide 0.28s cubic-bezier(0.175,0.885,0.32,1.275);
}
@keyframes mslide { from{transform:translateY(22px);opacity:0}to{transform:translateY(0);opacity:1} }
.modal-close {
    position:absolute; top:0.85rem; right:0.85rem;
    background:rgba(255,255,255,0.05); border:1px solid var(--border);
    color:var(--muted); width:28px; height:28px; border-radius:50%;
    display:flex; align-items:center; justify-content:center;
    cursor:pointer; transition:0.2s; font-size:0.76rem;
}
.modal-close:hover { background:var(--red); color:#fff; border-color:var(--red); }
.modal-header { display:flex; align-items:center; gap:0.9rem; margin-bottom:0.9rem; }
.modal-icon { font-size:2.2rem; }
.modal-title { font-size:1rem; font-weight:800; color:var(--text); }
.modal-sub { font-size:0.7rem; color:var(--muted); }
.learn-tabs {
    display:flex; gap:0.35rem; flex-wrap:wrap; margin-bottom:0.9rem;
    border-bottom:1px solid var(--border); padding-bottom:0.6rem;
}
.learn-tab {
    background:transparent; border:1px solid var(--border); color:var(--muted);
    padding:0.22rem 0.65rem; border-radius:7px; font-size:0.72rem; font-weight:700;
    cursor:pointer; transition:0.18s; font-family:inherit;
}
.learn-tab:hover { color:var(--accent); border-color:var(--accent); }
.learn-tab.active { background:var(--accent); border-color:var(--accent); color:#030f0a; }
.learn-section { display:none; }
.learn-section.active { display:block; }
.learn-highlight {
    background:rgba(16,185,129,0.07); border-left:3px solid var(--accent);
    border-radius:7px; padding:0.75rem 0.9rem; font-size:0.8rem;
    color:#86efac; font-style:italic; line-height:1.6; margin-bottom:0.9rem;
}
.learn-steps { display:flex; flex-direction:column; gap:0.55rem; }
.learn-step { display:flex; gap:0.65rem; font-size:0.78rem; color:#94a3b8; line-height:1.6; }
.learn-step strong { color:var(--text); }
.learn-step em { color:var(--teal); font-style:normal; font-weight:700; }
.ls-num {
    background:rgba(16,185,129,0.12); color:var(--accent); border-radius:50%;
    width:28px; height:28px; min-width:28px;
    display:flex; align-items:center; justify-content:center; font-size:0.65rem; font-weight:800;
}

/* ── RESPONSIVE ──────────────────────────────────────────── */