:root {
    --bg-primary: #060a12;
    --bg-secondary: #0d1423;
    --bg-tertiary: #141f36;
    --border: #203153;
    --text: #e8eaed;
    --muted: #8b95a5;
    --cyan: #00e5ff;
    --pink: #ff4081;
    --orange: #ff9100;
    --green: #76ff03;
    --danger: #ff1744;
    --font-display: 'Orbitron', sans-serif;
    --font-body: 'Rajdhani', sans-serif;
    --font-mono: 'JetBrains Mono', monospace;
}

* { box-sizing: border-box; }
html, body {
    margin: 0;
    width: 100%;
    height: 100%;
    overflow: hidden;
    background: radial-gradient(circle at 30% 20%, #12213f 0%, var(--bg-primary) 45%, #04070d 100%);
    color: var(--text);
    font-family: var(--font-body);
}

#app {
    height: 100%;
    display: grid;
    grid-template-rows: auto 1fr;
}

.topbar {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 10px 16px;
    background: rgba(13, 20, 35, 0.9);
    border-bottom: 1px solid var(--border);
}

.brand {
    display: flex;
    align-items: center;
    gap: 14px;
}

.back-link {
    color: var(--cyan);
    text-decoration: none;
    font-weight: 600;
    font-size: 14px;
}

.brand h1 {
    margin: 0;
    font-family: var(--font-display);
    font-size: 20px;
    letter-spacing: 1px;
}

.main-grid {
    min-height: 0;
    display: grid;
    grid-template-columns: 270px 1fr 270px;
}

.panel {
    min-height: 0;
    overflow: auto;
    padding: 12px;
    background: rgba(13, 20, 35, 0.9);
}

.controls { border-right: 1px solid var(--border); }
.readout { border-left: 1px solid var(--border); }

.group {
    border: 1px solid var(--border);
    border-radius: 10px;
    padding: 10px;
    margin-bottom: 10px;
    background: rgba(20, 31, 54, 0.45);
}

.group h2 {
    margin: 0 0 8px;
    font-family: var(--font-display);
    font-size: 12px;
    color: var(--cyan);
    text-transform: uppercase;
    letter-spacing: 1px;
}

.tool-row,
.preset-grid {
    display: grid;
    grid-template-columns: repeat(2, minmax(0, 1fr));
    gap: 6px;
}

.gauss-shape-row {
    margin-top: 4px;
}

.btn {
    border: 1px solid var(--border);
    background: var(--bg-tertiary);
    color: var(--text);
    border-radius: 8px;
    padding: 8px;
    cursor: pointer;
    font-family: var(--font-body);
    font-weight: 600;
    font-size: 13px;
}

.btn:hover {
    border-color: var(--cyan);
    color: var(--cyan);
}

.btn.active {
    border-color: var(--cyan);
    color: var(--cyan);
    background: rgba(0, 229, 255, 0.1);
}

.gauss-shape.active {
    border-color: var(--orange);
    color: var(--orange);
    background: rgba(255, 145, 0, 0.1);
}

.btn.danger:hover {
    border-color: var(--danger);
    color: var(--danger);
}

.slider-label {
    display: block;
    margin-top: 8px;
    margin-bottom: 2px;
    color: var(--muted);
    font-size: 12px;
    text-transform: uppercase;
    letter-spacing: 0.6px;
}

input[type="range"] {
    width: 100%;
}

.kv {
    display: flex;
    align-items: center;
    justify-content: space-between;
    margin: 5px 0;
    color: var(--muted);
    font-size: 13px;
}

.hint {
    color: var(--muted);
    font-size: 12px;
    line-height: 1.4;
    margin: 8px 0 0;
}

.sim-wrap {
    position: relative;
    min-width: 0;
    min-height: 0;
}

#sim-canvas {
    width: 100%;
    height: 100%;
    display: block;
    cursor: crosshair;
}

.overlay {
    position: absolute;
    top: 10px;
    left: 10px;
    font-family: var(--font-mono);
    font-size: 12px;
    color: var(--green);
    border: 1px solid rgba(118, 255, 3, 0.4);
    background: rgba(8, 16, 24, 0.7);
    border-radius: 8px;
    padding: 6px 10px;
}

.mono {
    font-family: var(--font-mono);
    font-size: 12px;
    color: #c6d2e3;
    white-space: pre-line;
    background: rgba(6, 10, 18, 0.75);
    border: 1px solid var(--border);
    border-radius: 8px;
    padding: 8px;
    margin-bottom: 8px;
}

.formula {
    font-family: var(--font-mono);
    font-size: 11px;
    color: #9bb3d0;
    margin-top: 5px;
}

.top-actions {
    display: flex;
    gap: 8px;
}

#mobile-backdrop,
#mobile-dock {
    display: none;
}

@media (max-width: 1100px) {
    .main-grid { grid-template-columns: 250px 1fr; }
    .readout { display: none; }
}

@media (max-width: 760px) {
    html, body {
        overflow: hidden;
    }

    #app {
        position: relative;
    }

    .topbar {
        padding: 8px 10px;
        gap: 8px;
    }

    .top-actions {
        gap: 6px;
    }

    .top-actions .btn {
        padding: 7px 9px;
        font-size: 12px;
    }

    .main-grid {
        grid-template-columns: 1fr;
        min-height: 0;
        position: relative;
    }

    .sim-wrap {
        min-height: calc(100dvh - 52px - 66px);
    }

    .controls,
    .readout {
        display: block;
        position: fixed;
        left: 0;
        right: 0;
        top: 52px;
        bottom: 66px;
        z-index: 40;
        border: none;
        border-top: 1px solid var(--border);
        transform: translateY(105%);
        transition: transform 0.24s ease;
        box-shadow: 0 -8px 28px rgba(0, 0, 0, 0.45);
        background: rgba(13, 20, 35, 0.98);
    }

    #app.show-controls #controls-panel,
    #app.show-readout #readout-panel {
        transform: translateY(0);
    }

    #mobile-backdrop {
        display: block;
        position: fixed;
        inset: 0;
        z-index: 35;
        background: rgba(6, 10, 18, 0.65);
        opacity: 0;
        pointer-events: none;
        transition: opacity 0.2s ease;
    }

    #app.mobile-panel-open #mobile-backdrop {
        opacity: 1;
        pointer-events: auto;
    }

    #mobile-dock {
        display: grid;
        grid-template-columns: repeat(2, minmax(0, 1fr));
        gap: 8px;
        position: fixed;
        left: 10px;
        right: 10px;
        bottom: 8px;
        z-index: 45;
        padding: 8px;
        border: 1px solid var(--border);
        border-radius: 12px;
        background: rgba(8, 14, 22, 0.94);
        backdrop-filter: blur(4px);
    }

    .mobile-btn {
        min-height: 42px;
        font-size: 14px;
    }

    .mobile-btn.active {
        border-color: var(--cyan);
        color: var(--cyan);
        background: rgba(0, 229, 255, 0.12);
    }

    .brand h1 { font-size: 16px; }

    .back-link {
        font-size: 12px;
    }
}