h1 {
    color: #0056b3;
    margin-top: 0;
    margin-bottom: 10px;
}

.intro {
    max-width: 700px;
    margin: 0 auto 25px auto;
    line-height: 1.6;
    font-size: 1.1em;
    color: #555;
}



.how-it-works {
    background-color: #e9f4ff;
    border: 1px solid #bde0ff;
    border-radius: 8px;
    padding: 20px;
    margin-bottom: 30px;
    text-align: left;
}

.how-it-works h2 {
    text-align: center;
    margin-top: 0;
    color: #0056b3;
    font-size: 1.5em;
    margin-bottom: 15px;
}

.explanation-columns {
    display: flex;
    gap: 25px;
    justify-content: space-between;
}

.explanation-columns .column {
    flex: 1;
}

.explanation-columns h3 {
    font-size: 1.1em;
    color: #004a99;
    border-bottom: 2px solid #bde0ff;
    padding-bottom: 5px;
    margin-top: 0;
    margin-bottom: 10px;
}

.explanation-columns p {
    font-size: 0.95em;
    line-height: 1.5;
    color: #333;
}

#data-container {
    display: grid;
    grid-template-columns: repeat(20, 1fr);
    grid-template-rows: repeat(50, 1fr);
    grid-auto-flow: column;
    gap: 3px;
    margin-bottom: 20px;
    padding: 10px;
    border: 1px solid #e0e0e0;
    border-radius: 8px;
    background-color: #f8f9fa;
    height: 200px;
    overflow-x: auto;
    overflow-y: hidden;
}

.legend {
    display: flex;
    justify-content: center;
    gap: 30px;
    margin-bottom: 20px;
    font-size: 0.9em;
}

.legend-item {
    display: flex;
    align-items: center;
    gap: 8px;
}

.legend-color {
    width: 16px;
    height: 16px;
    border-radius: 50%;
    display: inline-block;
}

.legend-label {
    font-weight: 600;
    letter-spacing: .2px;
}

.legend-item .train-color+.legend-label {
    color: var(--train-color);
}

.legend-item .test-color+.legend-label {
    color: var(--test-color);
}

.legend-item .fold-color+.legend-label {
    background: linear-gradient(45deg,
            color-mix(in srgb, var(--fold-color-1) 65%, #000) 0%,
            color-mix(in srgb, var(--fold-color-5) 65%, #000) 50%,
            color-mix(in srgb, var(--fold-color-6) 65%, #000) 100%);
    background-clip: text;
    -webkit-background-clip: text;
    color: transparent;
}

.train-color {
    background-color: var(--train-color);
}

.test-color {
    background-color: var(--test-color);
}

.fold-color {
    background: linear-gradient(45deg,
            var(--fold-color-1) 0%, var(--fold-color-2) 20%,
            var(--fold-color-3) 40%, var(--fold-color-4) 60%,
            var(--fold-color-5) 80%, var(--fold-color-6) 100%);
}

.data-point {
    width: 100%;
    height: 100%;
    border-radius: 50%;
    background-color: #ccc;
    transition: all 0.3s ease;
    min-width: 8px;
    min-height: 8px;
}

.data-point.train {
    background-color: var(--train-color);
}

.data-point.test {
    background-color: var(--test-color);
}

.data-point.is-training {
    opacity: 0.2;
}

.data-point.is-testing {
    opacity: 1;
    border: 3px solid var(--test-border-color);
    box-shadow: 0 0 8px var(--test-border-color);
    transform: scale(1.1);
}

.fold-1 {
    background-color: var(--fold-color-1);
}

.fold-2 {
    background-color: var(--fold-color-2);
}

.fold-3 {
    background-color: var(--fold-color-3);
}

.fold-4 {
    background-color: var(--fold-color-4);
}

.fold-5 {
    background-color: var(--fold-color-5);
}

.fold-6 {
    background-color: var(--fold-color-6);
}

.fold-7 {
    background-color: var(--fold-color-7);
}

.fold-8 {
    background-color: var(--fold-color-8);
}

.fold-9 {
    background-color: var(--fold-color-9);
}

.fold-10 {
    background-color: var(--fold-color-10);
}

.demo-controls {
    display: flex;
    flex-wrap: wrap;
    gap: 20px;
    justify-content: center;
    margin-bottom: 20px;
    padding: 20px 0;
    border-top: 1px solid #e0e0e0;
    border-bottom: 1px solid #e0e0e0;
}

.control-group {
    flex: 1;
    min-width: 300px;
    max-width: 500px;
    padding: 15px;
    background-color: #f8f9fa;
    border-radius: 8px;
    border: 1px solid #e9ecef;
    display: flex;
    flex-direction: column;
    justify-content: space-between;
}

.control-group h3 {
    margin-top: 0;
    color: #0056b3;
}

.control-group p {
    font-size: 0.9em;
    color: #666;
    margin-bottom: 15px;
    flex-grow: 1;
}

.button-controls {
    display: flex;
    flex-direction: column;
    gap: 15px;
    align-items: center;
}

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

.button-group {
    display: flex;
    gap: 10px;
    flex-wrap: wrap;
    justify-content: center;
}

#controls button,
.global-controls button {
    padding: 10px 15px;
    font-size: 1em;
    cursor: pointer;
    border-radius: 5px;
    border: 1px solid transparent;
    color: white;
    transition: background-color 0.2s ease, opacity 0.2s ease;
    min-width: 140px;
}

#run-simple-split-btn {
    background-color: #007bff;
    border-color: #007bff;
}

#run-k-fold-btn {
    background-color: #28a745;
    border-color: #28a745;
}

.global-controls {
    margin-bottom: 20px;
}

#regenerate-data-btn {
    background-color: #6c757d;
    border-color: #6c757d;
}

#regenerate-data-btn:hover:not(:disabled) {
    background-color: #545b62;
}

#run-simple-split-btn:hover:not(:disabled) {
    background-color: #0056b3;
}

#run-k-fold-btn:hover:not(:disabled) {
    background-color: #218838;
}

#controls button:disabled,
.global-controls button:disabled {
    opacity: 0.65;
    cursor: not-allowed;
}

#controls input[type="number"] {
    width: 60px;
    padding: 8px;
    border-radius: 5px;
    border: 1px solid #ced4da;
    text-align: center;
}

.demo-results {
    display: flex;
    flex-wrap: wrap;
    gap: 20px;
    justify-content: space-around;
    text-align: left;
    min-height: 220px;
    background-color: #f8f9fa;
    border: 1px solid #e9ecef;
    border-radius: 8px;
    padding: 20px;
}

.demo-results>.result-group {
    flex: 1;
    min-width: 300px;
    padding: 0 15px;
}

.demo-results>.result-group:first-child {
    border-right: 1px solid #e0e0e0;
}

@media (max-width: 768px) {
    .demo-results>.result-group:first-child {
        border-right: none;
        border-bottom: 1px solid #e0e0e0;
        padding-bottom: 15px;
        margin-bottom: 15px;
    }
}

#results h4 {
    color: #0056b3;
    margin-bottom: 5px;
    border-bottom: 1px solid #ddd;
    padding-bottom: 5px;
}

#results h5 {
    font-size: 0.9em;
    color: #555;
    margin: 15px 0 5px 0;
}

#simple-result-latest,
#k-fold-final-result-latest {
    font-size: 1.4em;
    margin-top: 5px;
    font-weight: bold;
    min-height: 2.2em;
    /* Prevents layout jumps */
}

#simple-result-latest {
    color: #0056b3;
}

#k-fold-final-result-latest {
    color: #218838;
}

#k-fold-process {
    font-family: 'Courier New', Courier, monospace;
    background-color: #fff;
    padding: 10px;
    border-radius: 5px;
    height: 120px;
    overflow-y: auto;
    border: 1px solid #e9ecef;
    margin-top: 10px;
    display: none;
    /* Hidden by default */
}

#k-fold-process.visible {
    display: block;
}

#k-fold-process p {
    margin: 5px 0;
    font-size: 0.95em;
}

.history-log {
    background-color: #fff;
    border: 1px solid #e9ecef;
    border-radius: 5px;
    padding: 8px;
    min-height: 50px;
    max-height: 100px;
    overflow-y: auto;
    display: flex;
    flex-wrap: wrap;
    gap: 6px;
}

.history-item {
    background-color: #e9ecef;
    padding: 4px 8px;
    border-radius: 4px;
    font-family: 'Courier New', Courier, monospace;
    font-size: 0.95em;
    color: #495057;
}

.history-item.lucky {
    background-color: #d4edda;
    color: #155724;
}

.history-item.unlucky {
    background-color: #f8d7da;
    color: #721c24;
}