:root {
    --bg-primary: #0d1117;
    --bg-secondary: #161b22;
    --bg-tertiary: #21262d;
    --text-primary: #f0f6fc;
    --text-secondary: #8b949e;
    --accent-blue: #58a6ff;
    --accent-green: #39d353;
    --accent-red: #f85149;
    --accent-yellow: #d29922;
    --border-color: #30363d;
    --glow-blue: rgba(88, 166, 255, 0.4);
    --glow-green: rgba(57, 211, 83, 0.4);
}

* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen, Ubuntu, sans-serif;
    background: var(--bg-primary);
    color: var(--text-primary);
    min-height: 100vh;
    line-height: 1.5;
}

.container {
    max-width: 480px;
    margin: 0 auto;
    padding: 24px 16px;
    min-height: 100vh;
    display: flex;
    flex-direction: column;
}

/* Header */
header {
    text-align: center;
    margin-bottom: 32px;
}

.logo {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 12px;
    margin-bottom: 8px;
}

.battery-icon {
    width: 32px;
    height: 32px;
    color: var(--accent-green);
}

.battery-fill {
    fill: var(--accent-green);
    opacity: 0.3;
}

h1 {
    font-size: 1.75rem;
    font-weight: 600;
    letter-spacing: -0.02em;
}

.subtitle {
    color: var(--text-secondary);
    font-size: 0.9rem;
}

/* Main Content */
main {
    flex: 1;
    display: flex;
    flex-direction: column;
    gap: 24px;
}

/* Control Panel */
.control-panel {
    display: flex;
    justify-content: center;
    padding: 20px 0;
}

.toggle-btn {
    width: 160px;
    height: 160px;
    border-radius: 50%;
    border: 3px solid var(--accent-blue);
    background: var(--bg-secondary);
    color: var(--accent-blue);
    cursor: pointer;
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    gap: 8px;
    font-size: 1.1rem;
    font-weight: 600;
    letter-spacing: 0.1em;
    transition: all 0.3s ease;
    position: relative;
    overflow: hidden;
}

.toggle-btn::before {
    content: '';
    position: absolute;
    inset: -2px;
    border-radius: 50%;
    background: linear-gradient(135deg, var(--accent-blue), var(--accent-green));
    opacity: 0;
    z-index: -1;
    transition: opacity 0.3s ease;
}

.toggle-btn:hover {
    transform: scale(1.05);
    box-shadow: 0 0 30px var(--glow-blue);
}

.toggle-btn:active {
    transform: scale(0.98);
}

.toggle-btn.running {
    border-color: var(--accent-green);
    color: var(--accent-green);
    box-shadow: 0 0 40px var(--glow-green);
    animation: pulse 2s ease-in-out infinite;
}

.toggle-btn.running::before {
    opacity: 0.1;
}

@keyframes pulse {
    0%, 100% {
        box-shadow: 0 0 30px var(--glow-green);
    }
    50% {
        box-shadow: 0 0 50px var(--glow-green), 0 0 80px var(--glow-green);
    }
}

.btn-icon {
    width: 40px;
    height: 40px;
}

.play-icon, .stop-icon {
    width: 100%;
    height: 100%;
}

.stop-icon {
    display: none;
}

.toggle-btn.running .play-icon {
    display: none;
}

.toggle-btn.running .stop-icon {
    display: block;
}

.toggle-btn.running .btn-text {
    display: none;
}

.toggle-btn.running .btn-text::after {
    content: 'STOP';
}

.toggle-btn.running .btn-text {
    display: block;
}

.toggle-btn.running .btn-text::before {
    content: 'STOP';
}

.toggle-btn:not(.running) .btn-text::before {
    content: 'START';
}

.btn-text {
    font-size: 0;
}

.btn-text::before {
    font-size: 1.1rem;
}

/* Intensity Panel */
.intensity-panel {
    background: var(--bg-secondary);
    border: 1px solid var(--border-color);
    border-radius: 12px;
    padding: 20px;
}

.intensity-label {
    display: block;
    text-align: center;
    color: var(--text-secondary);
    font-size: 0.85rem;
    text-transform: uppercase;
    letter-spacing: 0.05em;
    margin-bottom: 12px;
}

.intensity-buttons {
    display: flex;
    gap: 8px;
}

.intensity-btn {
    flex: 1;
    padding: 12px 8px;
    border: 1px solid var(--border-color);
    border-radius: 8px;
    background: var(--bg-tertiary);
    color: var(--text-secondary);
    font-size: 0.85rem;
    font-weight: 500;
    cursor: pointer;
    transition: all 0.2s ease;
}

.intensity-btn:hover {
    border-color: var(--accent-blue);
    color: var(--text-primary);
}

.intensity-btn.active {
    background: var(--accent-blue);
    border-color: var(--accent-blue);
    color: var(--bg-primary);
}

.intensity-btn[data-level="high"].active {
    background: var(--accent-yellow);
    border-color: var(--accent-yellow);
    color: var(--bg-primary);
}

.intensity-btn[data-level="maximum"].active {
    background: var(--accent-red);
    border-color: var(--accent-red);
    color: var(--text-primary);
    animation: max-pulse 1.5s ease-in-out infinite;
}

@keyframes max-pulse {
    0%, 100% { box-shadow: 0 0 0 rgba(248, 81, 73, 0); }
    50% { box-shadow: 0 0 15px rgba(248, 81, 73, 0.5); }
}

/* Status Panel */
.status-panel {
    background: var(--bg-secondary);
    border: 1px solid var(--border-color);
    border-radius: 12px;
    padding: 20px;
}

.status-title {
    font-size: 0.85rem;
    text-transform: uppercase;
    letter-spacing: 0.05em;
    color: var(--text-secondary);
    margin-bottom: 16px;
    text-align: center;
}

.status-grid {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 16px;
}

.status-item {
    display: flex;
    flex-direction: column;
    gap: 4px;
}

.status-label {
    font-size: 0.75rem;
    color: var(--text-secondary);
    text-transform: uppercase;
    letter-spacing: 0.03em;
}

.status-value {
    font-size: 0.95rem;
    font-weight: 500;
    display: flex;
    align-items: center;
    gap: 8px;
}

.status-dot {
    width: 8px;
    height: 8px;
    border-radius: 50%;
    background: var(--text-secondary);
}

.status-value.active .status-dot {
    background: var(--accent-green);
    box-shadow: 0 0 8px var(--accent-green);
    animation: blink 1s ease-in-out infinite;
}

@keyframes blink {
    0%, 100% { opacity: 1; }
    50% { opacity: 0.5; }
}

/* GPU Canvas */
#gpuCanvas {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    z-index: -1;
    opacity: 0.15;
    pointer-events: none;
}

/* Footer */
footer {
    text-align: center;
    padding: 24px 0 16px;
    color: var(--text-secondary);
    font-size: 0.8rem;
}

.footer-tip {
    margin-bottom: 16px;
}

/* Tech Info */
.tech-info {
    background: var(--bg-secondary);
    border: 1px solid var(--border-color);
    border-radius: 8px;
    text-align: left;
    font-size: 0.75rem;
}

.tech-info summary {
    padding: 10px 14px;
    cursor: pointer;
    color: var(--text-secondary);
    font-weight: 500;
    list-style: none;
    display: flex;
    align-items: center;
    gap: 6px;
}

.tech-info summary::-webkit-details-marker {
    display: none;
}

.tech-info summary::before {
    content: '';
    width: 0;
    height: 0;
    border-left: 5px solid var(--text-secondary);
    border-top: 4px solid transparent;
    border-bottom: 4px solid transparent;
    transition: transform 0.2s ease;
}

.tech-info[open] summary::before {
    transform: rotate(90deg);
}

.tech-info summary:hover {
    color: var(--text-primary);
}

.tech-list {
    padding: 0 14px 12px 14px;
    margin: 0;
    list-style: none;
    color: var(--text-secondary);
    line-height: 1.7;
}

.tech-list li {
    padding: 4px 0;
    border-top: 1px solid var(--border-color);
}

.tech-list strong {
    color: var(--accent-blue);
    font-weight: 500;
}

/* Responsive */
@media (max-width: 360px) {
    .container {
        padding: 16px 12px;
    }

    .toggle-btn {
        width: 130px;
        height: 130px;
    }

    .btn-icon {
        width: 32px;
        height: 32px;
    }

    h1 {
        font-size: 1.35rem;
    }

    .subtitle {
        font-size: 0.8rem;
    }

    .intensity-btn {
        padding: 10px 6px;
        font-size: 0.8rem;
    }

    .status-grid {
        gap: 12px;
    }

    .status-label {
        font-size: 0.7rem;
    }

    .status-value {
        font-size: 0.85rem;
    }
}

@media (max-width: 320px) {
    .toggle-btn {
        width: 120px;
        height: 120px;
    }

    h1 {
        font-size: 1.2rem;
    }

    .intensity-buttons {
        gap: 4px;
    }

    .intensity-btn {
        padding: 8px 4px;
        font-size: 0.75rem;
    }
}

@media (min-width: 481px) {
    .container {
        padding: 32px 24px;
    }

    header {
        margin-bottom: 40px;
    }

    .toggle-btn {
        width: 180px;
        height: 180px;
    }

    .intensity-btn {
        padding: 14px 16px;
        font-size: 0.9rem;
    }
}

@media (min-height: 800px) {
    .control-panel {
        padding: 40px 0;
    }
}

/* Landscape mode on mobile */
@media (max-height: 500px) and (orientation: landscape) {
    .container {
        padding: 12px 16px;
    }

    header {
        margin-bottom: 16px;
    }

    .toggle-btn {
        width: 100px;
        height: 100px;
    }

    .btn-icon {
        width: 28px;
        height: 28px;
    }

    .btn-text::before {
        font-size: 0.9rem;
    }

    .control-panel {
        padding: 8px 0;
    }

    main {
        gap: 12px;
    }

    .intensity-panel,
    .status-panel {
        padding: 12px;
    }

    .intensity-label,
    .status-title {
        margin-bottom: 8px;
    }
}

/* Running state enhancements */
body.draining {
    background: linear-gradient(135deg, var(--bg-primary) 0%, #0a1628 100%);
}

body.draining .battery-fill {
    animation: battery-drain 3s ease-in-out infinite;
}

@keyframes battery-drain {
    0%, 100% {
        width: 14px;
        fill: var(--accent-green);
    }
    50% {
        width: 6px;
        fill: var(--accent-yellow);
    }
}