:root {
    --bg-deep: #020617;
    --panel-glass: rgba(15, 23, 42, 0.7);
    --accent-blue: #38bdf8;
    --accent-gold: #fbbf24;
    --accent-green: #10b981;
    --text-primary: #ffffff;
    --text-secondary: #cbd5e1;
    --border-light: rgba(255, 255, 255, 0.1);
}

html,
body {
    margin: 0;
    padding: 0;
    width: 100%;
    height: 100%;
    overflow: hidden;
    background: #020617;
}

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

body.lab-theme {
    font-family: 'Inter', sans-serif;
    color: var(--text-primary);
}

nav {
    position: relative !important;
    background: #ffffff !important;
    border-bottom: 1px solid rgba(0, 0, 0, 0.1) !important;
    color: #0f172a !important;
    height: 60px;
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 0 30px;
    flex-shrink: 0;
    top: 0 !important;
    z-index: 1000;
}

.logo a {
    text-decoration: none;
    color: inherit;
    font-weight: 800;
    font-size: 1.5rem;
}

.nav-links {
    list-style: none;
    display: flex;
    gap: 20px;
}

.nav-links a {
    text-decoration: none;
    color: #64748b;
    font-weight: 600;
    transition: color 0.2s;
}

.nav-links a:hover {
    color: var(--accent-blue);
}

.lab-app {
    display: grid;
    grid-template-columns: 1fr 340px;
    flex: 1;
    overflow: hidden;
}

@media (max-width: 1024px) {
    .lab-app {
        grid-template-columns: 1fr 260px;
    }
}

.control-center {
    background: rgba(7, 10, 25, 0.9);
    border-left: 1px solid var(--border-light);
    padding: 30px;
    display: flex;
    flex-direction: column;
    gap: 25px;
    overflow-y: auto;
}

.mode-selector {
    display: grid;
    gap: 12px;
}

.mode-btn {
    background: var(--panel-glass);
    border: 1px solid var(--border-light);
    border-radius: 12px;
    padding: 15px;
    display: flex;
    align-items: center;
    gap: 15px;
    cursor: pointer;
    transition: all 0.2s ease;
    text-align: left;
}

.mode-btn.active {
    background: rgba(56, 189, 248, 0.1);
    border-color: var(--accent-blue);
    box-shadow: 0 0 20px rgba(56, 189, 248, 0.1);
}

.mode-btn .label { display: block; font-weight: 700; color: var(--text-primary); }
.mode-btn .desc { font-size: 0.75rem; color: var(--text-secondary); }

.stats-card {
    background: var(--panel-glass);
    border: 1px solid var(--border-light);
    border-radius: 16px;
    padding: 24px;
}

.card-header {
    display: flex;
    align-items: center;
    gap: 10px;
    margin-bottom: 20px;
}

.status-dot {
    width: 8px;
    height: 8px;
    background: var(--accent-green);
    border-radius: 50%;
    box-shadow: 0 0 8px var(--accent-green);
}

.math-display {
    text-align: center;
    margin-bottom: 25px;
}

.formula {
    font-size: 0.85rem;
    color: var(--text-secondary);
    font-family: 'JetBrains Mono', monospace;
    margin-bottom: 10px;
}

.equation {
    font-size: 1.6rem;
    font-weight: 800;
    color: var(--accent-blue);
    margin-bottom: 8px;
}

.verdict {
    font-size: 0.75rem;
    text-transform: uppercase;
    letter-spacing: 1px;
}

.verdict.highlight { color: var(--accent-gold); }
.verdict.success { color: var(--accent-green); }

/* Galvanometer Styling */
.meter-container {
    height: 60px;
    background: rgba(0,0,0,0.3);
    border-radius: 8px;
    position: relative;
    margin: 15px 0 10px;
    border: 1px solid var(--border-light);
    overflow: hidden;
}

.meter-scale {
    position: absolute;
    bottom: 5px;
    left: 10%;
    right: 10%;
    height: 10px;
    border-bottom: 2px solid var(--text-secondary);
    background-image: linear-gradient(to right, transparent 49%, var(--text-secondary) 50%, transparent 51%);
    background-size: 10% 100%;
}

.meter-needle {
    position: absolute;
    bottom: 5px;
    left: 50%;
    width: 2px;
    height: 40px;
    background: #ef4444;
    transform-origin: bottom center;
    transition: transform 0.1s cubic-bezier(0.18, 0.89, 0.32, 1.28);
    box-shadow: 0 0 10px rgba(239, 68, 68, 0.5);
}

#g-value {
    display: block;
    text-align: center;
    font-family: monospace;
    color: var(--accent-green);
    font-size: 0.9rem;
}

/* Toolbox */
.toolbox-compact h4 {
    font-size: 0.75rem;
    text-transform: uppercase;
    letter-spacing: 1px;
    color: var(--text-secondary);
    margin-bottom: 15px;
}

.modifier-row { margin-bottom: 15px; }
.modifier-info { display: flex; justify-content: space-between; align-items: center; margin-bottom: 8px; }
.modifier-info label { font-size: 0.8rem; color: var(--text-secondary); }
.modifier-info span { font-weight: 700; color: var(--accent-blue); }

input[type="range"] { width: 100%; accent-color: var(--accent-blue); }

.btn-reset {
    width: 100%;
    background: none;
    border: 1px solid var(--border-light);
    color: var(--text-secondary);
    padding: 12px;
    border-radius: 8px;
    cursor: pointer;
    margin-top: 10px;
}

/* Viewport */
.viewport {
    position: relative;
    overflow: hidden;
    background: radial-gradient(circle at 50% 50%, #0f172a 0%, #020617 100%);
}

#simCanvas { width: 100%; height: 100%; cursor: pointer; }

.lab-overlay {
    position: absolute;
    background: var(--panel-glass);
    backdrop-filter: blur(10px);
    border: 1px solid var(--border-light);
    padding: 15px;
    border-radius: 12px;
}

.top-right { top: 20px; right: 20px; }

.data-point { display: flex; flex-direction: column; margin-bottom: 10px; }
.data-point:last-child { margin-bottom: 0; }
.data-point .label { font-size: 0.65rem; text-transform: uppercase; color: var(--text-secondary); }
.data-point .value { font-size: 1.1rem; font-weight: 800; color: var(--text-primary); }

.interaction-hint {
    position: absolute;
    bottom: 30px;
    left: 50%;
    transform: translateX(-50%);
    background: rgba(0,0,0,0.6);
    padding: 10px 25px;
    border-radius: 30px;
    font-size: 0.85rem;
    color: var(--text-secondary);
    pointer-events: none;
}

.interaction-hint span { color: var(--accent-blue); font-weight: 700; }