* {
    box-sizing: border-box;
    font-family: system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
}

body {
    margin: 0;
    background: #0b1020;
    color: #f5f5f5;
}

#app {
    max-width: 1100px;
    margin: 0 auto;
    padding: 16px;
}

header {
    text-align: center;
    margin-bottom: 16px;
}

header h1 {
    margin-bottom: 4px;
}

main {
    display: grid;
    grid-template-columns: 2fr 1.2fr;
    gap: 16px;
}

.stage-row {
    display: flex;
    gap: 8px;
    margin-bottom: 20px;
    overflow: hidden;
    padding: 12px 4px;
}

.stage-box {
    flex: 1;
    padding: 10px;
    border-radius: 8px;
    border: 1px solid #555;
    text-align: center;
    font-size: 0.9rem;
    background: #1b2335;
    opacity: 0.5;
    transition: all 0.3s ease;
}

.stage-box {
    position: relative;
    display: flex;
    flex-direction: column;
    align-items: center;
    padding: 12px;
}

.stage-img {
    width: 40px;      /* Adjust size */
    height: 40px;
    margin-bottom: 4px;
    opacity: 0.6;
    transition: 0.3s;
}

.stage-box.active .stage-img {
    opacity: 1;
    transform: scale(1.15);        /* Slight zoom on active */
}


.stage-box.active {
    border-color: #4ade80;
    box-shadow: 0 0 15px rgba(74, 222, 128, 0.7);
    opacity: 1;
    transform: scale(1.05);
}

.system-diagram {
    display: flex;
    gap: 16px;
}

.memory, .disk {
    flex: 1;
    background: #151a2c;
    padding: 10px;
    border-radius: 10px;
    border: 1px solid #333;
}

.memory-blocks {
    display: flex;
    flex-direction: column;
    gap: 6px;
}

.mem-block {
    padding: 6px;
    border-radius: 6px;
    background: #1f2937;
    font-size: 0.8rem;
    border: 1px solid #374151;
    opacity: 0.4;
}

.mem-block.active {
    border-color: #60a5fa;
    box-shadow: 0 0 10px rgba(96, 165, 250, 0.7);
    opacity: 1;
}

.disk-sectors {
    display: flex;
    flex-direction: column;
    gap: 6px;
}

.sector {
    padding: 6px;
    border-radius: 6px;
    background: #1f2937;
    font-size: 0.8rem;
    border: 1px solid #374151;
    opacity: 0.4;
}

.sector.active {
    border-color: #f97316;
    box-shadow: 0 0 10px rgba(249, 115, 22, 0.7);
    opacity: 1;
}

#info-panel {
    background: #111827;
    padding: 16px;
    border-radius: 12px;
    border: 1px solid #374151;
}

#controls {
    display: flex;
    flex-wrap: wrap;
    gap: 8px;
    margin: 12px 0;
}

button {
    padding: 6px 12px;
    border-radius: 999px;
    border: none;
    cursor: pointer;
    background: #2563eb;
    color: #fff;
    font-size: 0.85rem;
}

button:disabled {
    background: #4b5563;
    cursor: not-allowed;
}

button:hover:not(:disabled) {
    filter: brightness(1.1);
}

footer {
    margin-top: 10px;
    text-align: center;
    font-size: 0.8rem;
    color: #9ca3af;
}

/* Small screens */
@media (max-width: 800px) {
    main {
        grid-template-columns: 1fr;
    }
}