:root {
    --bg-color: #121212;
    --grid-bg: #1e1e1e;
    --primary-color: #00ffcc;
    --secondary-color: #ff00ff;
    --accent-color: #ffff00;
    --text-color: #ffffff;
    --inactive-pad: #333;
    --active-pad: #00ffcc;
    --playing-pad: #ff00ff;
    --border-radius: 4px;
}

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

body {
    font-family: 'Courier New', Courier, monospace;
    background-color: var(--bg-color);
    color: var(--text-color);
    display: flex;
    justify-content: center;
    align-items: center;
    min-height: 100vh;
}

.app-container {
    width: 100%;
    max-width: 900px;
    padding: 20px;
    background: var(--grid-bg);
    border-radius: 8px;
    box-shadow: 0 0 20px rgba(0, 255, 204, 0.2);
    border: 1px solid #333;
}

header {
    margin-bottom: 20px;
    display: flex;
    justify-content: space-between;
    align-items: center;
    border-bottom: 1px solid #333;
    padding-bottom: 10px;
}

.back-link {
    color: var(--text-color);
    text-decoration: none;
    font-size: 0.9rem;
    opacity: 0.7;
    transition: opacity 0.2s;
}

.back-link:hover {
    opacity: 1;
    color: var(--primary-color);
}

h1 {
    font-size: 1.5rem;
    text-transform: uppercase;
    letter-spacing: 2px;
    color: var(--primary-color);
    text-shadow: 0 0 5px var(--primary-color);
}

.controls-top {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 20px;
    background: #111;
    padding: 15px;
    border-radius: var(--border-radius);
    border: 1px solid #333;
}

.control-btn {
    background: transparent;
    border: 2px solid var(--primary-color);
    color: var(--primary-color);
    padding: 8px 20px;
    font-family: inherit;
    font-size: 1rem;
    cursor: pointer;
    text-transform: uppercase;
    transition: all 0.2s;
    border-radius: var(--border-radius);
}

.control-btn:hover {
    background: var(--primary-color);
    color: var(--bg-color);
    box-shadow: 0 0 10px var(--primary-color);
}

.control-btn.active {
    background: var(--primary-color);
    color: var(--bg-color);
    box-shadow: 0 0 15px var(--primary-color);
}

.control-btn.secondary {
    border-color: var(--secondary-color);
    color: var(--secondary-color);
}

.control-btn.secondary:hover {
    background: var(--secondary-color);
    color: var(--bg-color);
    box-shadow: 0 0 10px var(--secondary-color);
}

.control-group {
    display: flex;
    align-items: center;
    gap: 10px;
}

input[type="range"] {
    -webkit-appearance: none;
    background: #333;
    height: 6px;
    border-radius: 3px;
    width: 150px;
}

input[type="range"]::-webkit-slider-thumb {
    -webkit-appearance: none;
    width: 16px;
    height: 16px;
    background: var(--accent-color);
    border-radius: 50%;
    cursor: pointer;
    box-shadow: 0 0 5px var(--accent-color);
}

.sequencer-container {
    display: flex;
    gap: 10px;
    margin-bottom: 20px;
    overflow-x: auto; /* Handle smaller screens */
    padding-bottom: 10px;
}

.track-labels {
    display: flex;
    flex-direction: column;
    justify-content: space-around;
    min-width: 80px;
    padding-top: 5px; /* Align roughly with pads */
}

.label {
    height: 40px;
    display: flex;
    align-items: center;
    font-size: 0.9rem;
    color: #888;
    text-transform: uppercase;
}

.grid {
    display: grid;
    grid-template-columns: repeat(16, 1fr);
    grid-template-rows: repeat(4, 1fr);
    gap: 6px;
    flex-grow: 1;
}

.pad {
    width: 30px;
    height: 40px;
    background-color: var(--inactive-pad);
    border: 1px solid #444;
    border-radius: 2px;
    cursor: pointer;
    transition: background-color 0.1s;
}

.pad:hover {
    background-color: #444;
}

.pad.active {
    background-color: var(--active-pad);
    box-shadow: 0 0 8px var(--active-pad);
    border-color: var(--active-pad);
}

/* Playing state styling */
.pad.playing {
    border-color: var(--text-color);
    transform: scale(0.95);
}

.pad.active.playing {
    background-color: var(--playing-pad);
    box-shadow: 0 0 12px var(--playing-pad);
    border-color: var(--playing-pad);
}

/* Beat markers */
.grid .pad:nth-child(4n+1) {
    border-left: 1px solid #666; /* Mild separation for beat start */
}

.instructions {
    text-align: center;
    color: #666;
    font-size: 0.8rem;
    margin-top: 10px;
}

/* Mobile Responsiveness */
@media (max-width: 768px) {
    .app-container {
        padding: 10px;
        max-width: 100%;
    }

    .grid {
        gap: 4px;
    }

    .pad {
        width: 20px;
        height: 30px;
    }

    .label {
        height: 30px;
        font-size: 0.7rem;
    }

    .controls-top {
        flex-direction: column;
        gap: 15px;
    }
}