:root {
    --bg-color: #0d1117; /* GitHub dark background */
    --text-color: #c9d1d9; /* GitHub dark text */
    --border-color: #30363d;
    --control-bg: #161b22;
    --control-hover-bg: #21262d;
    --button-bg: #238636;
    --button-hover-bg: #2ea043;
    --box-bg: #1f6feb; /* Brighter blue for boxes */
    --box-text: #ffffff;
    --comparing-bg: #dbab0a; /* Yellowish */
    --swapping-bg: #da3633; /* Reddish */
    --sorted-bg: #2ea043; /* Greenish */
    --box-shadow: 0 2px 5px rgba(0, 0, 0, 0.3);
}

body {
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Helvetica, Arial, sans-serif, "Apple Color Emoji", "Segoe UI Emoji";
    margin: 0;
    padding: 0;
    background-color: var(--bg-color);
    color: var(--text-color);
    display: flex;
    flex-direction: column;
    min-height: 100vh;
}

header {
    background-color: var(--control-bg);
    color: var(--text-color);
    padding: 1rem;
    text-align: center;
    border-bottom: 1px solid var(--border-color);
}

header h1 {
    margin: 0;
}

.controls {
    background-color: var(--control-bg);
    padding: 1rem;
    display: flex;
    flex-wrap: wrap;
    justify-content: center;
    align-items: center;
    gap: 1rem;
    border-bottom: 1px solid var(--border-color);
}

.control-group {
    display: flex;
    align-items: center;
    gap: 0.5rem;
}

.controls label {
    font-weight: 500;
}

.controls select,
.controls input[type="range"],
.controls button {
    padding: 0.5rem 0.8rem;
    border: 1px solid var(--border-color);
    border-radius: 6px;
    background-color: var(--control-hover-bg);
    color: var(--text-color);
    font-size: 0.9rem;
}

/* Style range inputs */
.controls input[type="range"] {
    cursor: pointer;
    padding: 0; /* Remove padding for range */
}

.controls button {
    background-color: var(--button-bg);
    color: var(--box-text);
    cursor: pointer;
    font-weight: 500;
    transition: background-color 0.2s ease;
}

.controls button:hover:not(:disabled) {
    background-color: var(--button-hover-bg);
}

.controls button:disabled {
    opacity: 0.6;
    cursor: not-allowed;
}

/* Style for Stop Button */
#stop {
    background-color: var(--swapping-bg); /* Use red color */
}
#stop:hover:not(:disabled) {
    background-color: #a40e26; /* Darker red on hover */
}

/* Utility class to hide elements */
.hidden {
    display: none !important;
}


#visualization-area {
    flex-grow: 1;
    display: flex;
    flex-direction: row;
    justify-content: center;
    align-items: center;
    padding: 2rem;
    /* Removed background color, inherits from body */
    min-height: 150px;
    gap: 8px; /* Slightly wider gap */
    overflow-x: auto;
    overflow-y: hidden;
    position: relative; /* Needed for absolute positioning of bars if we used that */
}

.bar {
    background-color: var(--box-bg);
    border: 1px solid var(--border-color);
    color: var(--box-text);
    font-weight: bold;
    display: flex;
    justify-content: center;
    align-items: center;
    width: 50px;
    height: 50px;
    border-radius: 6px; /* Rounded corners */
    box-shadow: var(--box-shadow);
    transition: background-color 0.3s ease, transform 0.3s ease; /* Add transform transition */
    flex-shrink: 0;
    position: relative; /* Required for smooth transition using transform */
    left: 0; /* Initial position for transform */
}

/* Colors for different states */
.bar.comparing {
    background-color: var(--comparing-bg);
    color: #111; /* Darker text on lighter background */
}

.bar.swapping {
    background-color: var(--swapping-bg);
}

.bar.sorted {
    background-color: var(--sorted-bg);
}

footer {
    background-color: var(--control-bg);
    color: var(--text-color);
    padding: 0.5rem;
    text-align: center;
    margin-top: auto;
    border-top: 1px solid var(--border-color);
    font-size: 0.8rem;
}

/* Optional: Subtle background gradient animation */
/* body {
    ... existing styles ...
    background: linear-gradient(-45deg, #0d1117, #161b22, #0d1117, #21262d);
    background-size: 400% 400%;
    animation: gradientBG 15s ease infinite;
}

@keyframes gradientBG {
    0% { background-position: 0% 50%; }
    50% { background-position: 100% 50%; }
    100% { background-position: 0% 50%; }
} */


/* Responsive adjustments */
@media (max-width: 768px) {
    .controls {
        flex-direction: column;
        align-items: stretch; /* Make controls take full width */
    }
    .control-group {
        justify-content: space-between; /* Space out label and control */
    }
    #visualization-area {
        padding: 1rem;
    }
}