:root {
    --q-bg: #0b0c10;
    --q-grid-line: rgba(255, 255, 255, 0.1);
    --gate-h-color: #3b82f6;
    --gate-x-color: #ef4444;
    --gate-y-color: #f59e0b;
    --gate-z-color: #10b981;
    --gate-cx-color: #8b5cf6;
    --gate-m-color: #64748b;
}

body.quantum-bg {
    background: radial-gradient(circle at center, #1f2235 0%, #0b0c10 100%);
    color: #e2e8f0;
    font-family: 'Space Grotesk', sans-serif;
    min-height: 100vh;
}

.quantum-layout {
    display: grid;
    grid-template-columns: 250px 1fr 300px;
    gap: 20px;
    align-items: start;
}
@media(max-width: 992px) {
    .quantum-layout {
        grid-template-columns: 1fr;
    }
}

.gates-grid {
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: 10px;
}

.q-gate {
    width: 100%;
    height: 44px;
    border-radius: 8px;
    display: flex;
    align-items: center;
    justify-content: center;
    font-weight: bold;
    font-size: 1.1rem;
    cursor: grab;
    user-select: none;
    transition: transform 0.2s, box-shadow 0.2s;
    background: rgba(255,255,255,0.05);
    border: 1px solid rgba(255,255,255,0.1);
    color: white;
}
.q-gate:active { cursor: grabbing; transform: scale(0.95); }

.gate-h { border-color: var(--gate-h-color); box-shadow: 0 0 10px rgba(59,130,246,0.3); }
.gate-x { border-color: var(--gate-x-color); box-shadow: 0 0 10px rgba(239,68,68,0.3); }
.gate-y { border-color: var(--gate-y-color); box-shadow: 0 0 10px rgba(245,158,11,0.3); }
.gate-z { border-color: var(--gate-z-color); box-shadow: 0 0 10px rgba(16,185,129,0.3); }
.gate-cnot { border-color: var(--gate-cx-color); box-shadow: 0 0 10px rgba(139,92,246,0.3); }
.gate-m { border-color: var(--gate-m-color); }

.circuit-grid {
    display: flex;
    flex-direction: column;
    gap: 20px;
    position: relative;
    padding: 10px 0;
}

/* Base line across all rows */
.circuit-grid::before {
    content: '';
    position: absolute;
    top: 0; bottom: 0; left: 45px;
    width: 2px;
}

.qubit-row {
    display: flex;
    align-items: center;
    position: relative;
    height: 50px;
}

.qubit-label {
    width: 50px;
    font-weight: 700;
    color: #aaccff;
    flex-shrink: 0;
}

/* The wire */
.qubit-wire {
    position: absolute;
    left: 50px;
    right: 0;
    top: 50%;
    height: 2px;
    background: var(--q-grid-line);
    z-index: 0;
}

.slots-container {
    display: flex;
    gap: 10px;
    padding-left: 10px;
    z-index: 1;
    flex: 1;
}

.gate-slot {
    width: 50px;
    height: 50px;
    border: 2px dashed rgba(255,255,255,0.1);
    border-radius: 8px;
    display: flex;
    align-items: center;
    justify-content: center;
    transition: background 0.2s, border-color 0.2s;
    background: var(--q-bg);
}
.gate-slot.drag-over {
    background: rgba(255,255,255,0.1);
    border-color: #fff;
    border-style: solid;
}
.gate-slot.has-gate {
    border: none;
}

/* Gate instances inside circuit */
.gate-instance {
    width: 100%;
    height: 100%;
    border-radius: 8px;
    display: flex;
    align-items: center;
    justify-content: center;
    font-weight: bold;
    cursor: pointer;
}

/* Connecting line for CNOT */
.cnot-line {
    position: absolute;
    width: 2px;
    background: var(--gate-cx-color);
    z-index: 0;
    left: 50%;
    transform: translateX(-50%);
}

.prob-chart {
    display: flex;
    flex-direction: column;
    gap: 8px;
}
.prob-row {
    display: flex;
    align-items: center;
    gap: 10px;
}
.prob-label {
    width: 45px;
    font-family: monospace;
    font-size: 0.85rem;
    color: #aaccff;
}
.prob-bar-container {
    flex: 1;
    height: 12px;
    background: rgba(255,255,255,0.1);
    border-radius: 6px;
    overflow: hidden;
    position: relative;
}
.prob-bar {
    height: 100%;
    background: linear-gradient(90deg, #10b981, #3b82f6);
    width: 0%;
    transition: width 0.3s cubic-bezier(0.2, 0.8, 0.2, 1);
}
.prob-val {
    width: 35px;
    text-align: right;
    font-size: 0.8rem;
}