:root {
    --primary-color: #3b82f6;
    --primary-hover: #2563eb;
    --secondary-color: #64748b;
    --accent-color: #0ea5e9;
    --panel-bg: #ffffff;
    --text-main: #1f2937;
    --text-muted: #6b7280;
    --border-color: #e5e7eb;
    --shadow: 0 4px 6px -1px rgba(0, 0, 0, 0.1), 0 2px 4px -1px rgba(0, 0, 0, 0.06);
    --radius: 8px;
    --font-heading: 'Outfit', sans-serif;
    --font-body: 'Outfit', sans-serif;
}

body {
    margin: 0;
    padding: 0;
    font-family: var(--font-body);
    background: #e2e8f0;
    /* Darker background for better contrast */
    background-size: cover;
    background-attachment: fixed;
    background-position: center 6px;
    color: var(--text-main);
    min-height: 100vh;
    overflow-x: hidden;
    overflow-y: auto;
}

/* MAIN LAYOUT */
.app-container {
    max-width: 1400px;
    margin: 30px auto 40px auto;
    padding: 10px;
    display: flex;
    flex-direction: column;
    min-height: 100vh;
    box-sizing: border-box;
    justify-content: flex-start;
}

.main-grid {
    display: grid;
    grid-template-columns: 340px 1fr 340px;
    gap: 15px;
    /* Reduced gap */
    min-height: auto;
    overflow: visible;
}

/* PANELS */
.glass-panel {
    background: var(--panel-bg);
    box-shadow: 0 20px 25px -5px rgba(0, 0, 0, 0.15), 0 8px 10px -6px rgba(0, 0, 0, 0.1);
    /* Stronger shadow */
    border: 1px solid #94a3b8;
    /* Darker border */
    display: flex;
    flex-direction: column;
    overflow: visible;
    /* Reduced min heights specifically */
}

.panel-header {
    padding: 10px 15px;
    /* Compact */
    background: #f8fafc;
    border-bottom: 1px solid var(--border-color);
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.panel-header h2 {
    margin: 0;
    font-size: 0.95rem;
    /* Slightly smaller */
    font-weight: 700;
    color: #334155;
    text-transform: uppercase;
}

/* INPUT STYLES */
.input-panel {
    padding: 0;
}

.input-panel .input-group {
    padding: 10px 15px;
    /* Compact */
    border-bottom: 1px solid #f1f5f9;
}

.input-panel label {
    display: block;
    margin-bottom: 3px;
    font-size: 0.8rem;
    font-weight: 600;
    color: #475569;
}

.input-panel input[type="text"],
.input-panel input[type="number"] {
    width: 100%;
    padding: 6px 10px;
    border: 1px solid #cbd5e1;
    border-radius: 4px;
    font-family: var(--font-body);
    font-size: 0.9rem;
    outline: none;
    box-sizing: border-box;
    background: #ffffff;
}

input[type="range"] {
    width: 100%;
    margin-top: 5px;
    cursor: pointer;
}

/* BUTTONS */
.btn-group {
    padding: 5px 15px;
    display: flex;
    gap: 8px;
    justify-content: stretch;
}

.sub-controls {
    padding: 5px 15px;
}

button {
    padding: 8px;
    border: none;
    border-radius: 4px;
    font-family: var(--font-body);
    font-weight: 600;
    cursor: pointer;
    font-size: 0.85rem;
    flex: 1;
}

.primary-btn {
    background: var(--primary-color);
    color: white;
}

.primary-btn:hover {
    background: var(--primary-hover);
}

.secondary-btn {
    background: #f1f5f9;
    color: #334155;
    border: 1px solid #cbd5e1;
}

.secondary-btn:hover {
    background: #e2e8f0;
}

.outline-btn {
    background: white;
    border: 1px solid #ef4444;
    color: #ef4444;
}

.outline-btn:hover {
    background: #fef2f2;
}

/* PROCESSING VISUALIZATION */
.processing-panel {
    display: flex;
    flex-direction: column;
}

.viz-container {
    flex: 2;
    background: #f8fafc;
    border-bottom: 1px solid var(--border-color);
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: flex-start;
    padding: 15px;
    overflow-y: auto;
    /* User request: Make middle section scrollable */
    position: relative;
    justify-content: start;
    /* Reset from evenly */
}

.items-pool-section {
    width: 100%;
    border-bottom: 1px dashed #cbd5e1;
    display: flex;
    flex-direction: column;
    align-items: center;
    padding-bottom: 15px;
    margin-bottom: 15px;
    margin-top: 25px;
    order: 2;
}

.section-label {
    font-size: 0.8rem;
    color: var(--text-muted);
    margin-bottom: 8px;
    font-weight: 700;
    font-style: italic;
    width: 100%;
    text-align: center;
}

.items-row {
    display: flex;
    flex-wrap: wrap;
    gap: 8px;
    justify-content: center;
}

/* ITEM CARD */
.item-card {
    width: 60px;
    /* Smaller */
    background: white;
    border: 1px solid #e2e8f0;
    border-radius: 4px;
    text-align: center;
    padding: 4px;
    box-shadow: 0 1px 2px rgba(0, 0, 0, 0.1);
    transition: transform 0.2s;
    display: flex;
    flex-direction: column;
    align-items: center;
}

.item-card.active {
    border-color: var(--primary-color);
    box-shadow: 0 0 0 2px var(--primary-color);
    transform: translateY(-2px);
}

.item-card.taken {
    background: #f0fdf4;
    border-color: #22c55e;
    opacity: 0.7;
}

.item-visual {
    width: 100%;
    height: 30px;
    border-radius: 2px;
    margin-bottom: 2px;
    color: white;
    font-size: 0.7rem;
    display: flex;
    align-items: center;
    justify-content: center;
    font-weight: bold;
    flex-shrink: 0;
}

.item-info {
    font-size: 0.65rem;
    color: #334155;
}

.item-ratio {
    font-size: 0.6rem;
    color: var(--primary-color);
    font-weight: 700;
}

/* KNAPSACK */
.knapsack-wrapper {
    display: flex;
    flex-direction: column;
    align-items: center;
    width: 90%;
    margin-bottom: 15px;
    order: 1;
}

.knapsack-container {
    width: 100%;
    height: 40px;
    /* Slightly smaller but not 35 */
    border: 2px solid #334155;
    border-radius: 4px;
    background: #e2e8f0;
    position: relative;
    overflow: hidden;
}

.knapsack-fill {
    height: 100%;
    width: 0%;
    background: repeating-linear-gradient(45deg, var(--accent-color), var(--accent-color) 10px, #0891b2 10px, #0891b2 20px);
    transition: width 0.3s ease-in-out;
}

.knapsack-label {
    position: absolute;
    width: 100%;
    text-align: center;
    top: 50%;
    transform: translateY(-50%);
    font-weight: bold;
    color: #0f172a;
    pointer-events: none;
    z-index: 5;
    font-size: 0.8rem;
}

/* LEGEND */
/* LEGEND */
.viz-legend {
    position: relative;
    /* User preferred scrollable option with no overlap */
    bottom: auto;
    left: auto;
    margin-top: 10px;
    width: 100%;
    display: flex;
    justify-content: center;
    gap: 15px;
    background: transparent;
    padding: 5px 0;
    font-size: 0.75rem;
    color: #64748b;
    border-top: 1px dotted #e2e8f0;
    padding-top: 10px;
    order: 3;
}



/* PSEUDOCODE - COMPACT */
.pseudocode-section {
    flex: 0 0 auto;
    background: #e3edf0;
    color: #334155;
    padding: 10px 15px;
    font-family: 'Consolas', monospace;
    font-size: 0.85rem;
    overflow-y: visible;
    border-top: 1px solid var(--border-color);
    height: auto;
    /* Restored from fixed 140px */
}

.pseudocode-section h3 {
    display: block;
    margin: 0 0 5px 0;
    font-size: 0.8rem;
    color: #324c70;
}

.steps-list {
    list-style: none;
    padding: 0;
    margin: 0;
}

.steps-list li {
    padding: 3px 6px;
    margin-bottom: 2px;
    border-radius: 2px;
}

.steps-list li.active-step {
    background: #3b82f6;
    color: white;
}

/* OUTPUT */
.output-panel .result-card {
    text-align: center;
    padding: 10px;
    background: white;
    border: 1px solid #e2e8f0;
    color: var(--text-main);
    margin: 10px;
    border-radius: 8px;
}

.total-value {
    font-size: 2rem;
    font-weight: 700;
    margin-top: 2px;
    display: flex;
    justify-content: center;
    align-items: baseline;
}

.total-value::before {
    content: '₹';
    color: var(--primary-color);
    font-size: 1.2rem;
    margin-right: 2px;
}

.result-card h3 {
    margin: 0;
    font-weight: 400;
    font-size: 0.9rem;
    opacity: 0.9;
    text-transform: uppercase;
}

.result-details {
    padding: 0 10px;
    flex: 1;
    overflow-y: auto;
    display: flex;
    flex-direction: column;
}

/* RESULT TABLE STYLE */
.result-table {
    width: 100%;
    border-collapse: collapse;
    font-size: 0.8rem;
}

.result-table th,
.result-table td {
    padding: 5px;
    border-bottom: 1px solid #e2e8f0;
    text-align: left;
}

.result-table th {
    font-weight: 600;
    color: var(--text-muted);
}

.result-table td:last-child {
    text-align: right;
    font-weight: 600;
}

/* LOGS */
.log-console {
    background: #ffffff;
    color: #334155;
    font-family: 'Consolas', monospace;
    font-size: 0.75rem;
    padding: 10px;
    border-top: 1px solid #e2e8f0;
    height: 150px;
    /* Restored from 90px */
    display: flex;
    flex-direction: column;
}

.log-area {
    background: #f1f5f9;
    border: 1px solid #e2e8f0;
    border-radius: 4px;
    padding: 4px;
    flex: 1;
    overflow-y: auto;
}

.status-tag {
    background: #d1fae5;
    color: #065f46;
    padding: 2px 8px;
    border-radius: 99px;
    font-size: 0.7rem;
    font-weight: 700;
    text-transform: uppercase;
}

@media (max-width: 1100px) {
    .main-grid {
        grid-template-columns: 1fr;
        overflow: visible;
    }

    .app-container {
        height: auto;
    }
}

@media (max-width: 768px) {
    .app-container {
        margin: 12px 8px 40px;
    }

    .main-grid {
        grid-template-columns: 1fr;
        gap: 12px;
    }

    .glass-panel {
        min-height: auto;
    }

    .processing-panel .viz-container,
    .result-details,
    .log-console {
        max-height: none;
        overflow: visible;
    }

    .log-console {
        height: 170px;
    }

    #knapsackPopup {
        position: fixed;
        top: 8px;
        left: 50%;
        transform: translateX(-50%);
        width: calc(100% - 20px);
        max-width: 420px;
        z-index: 999;
    }
}




.knapsack-wrapper {
    display: flex;
    flex-direction: column;
    align-items: center;
    margin-top: auto;
    width: 90%;
    margin-bottom: 10px;
}

.knapsack-container {
    width: 100%;
    height: 45px;
    border: 2px solid #334155;
    border-radius: 4px;
    background: #e2e8f0;
    position: relative;
    overflow: hidden;
}

.knapsack-fill {
    height: 100%;
    width: 0%;
    background: transparent;
    transition: width 0.3s ease-in-out;
    display: flex;
    position: absolute;
    top: 0;
    left: 0;
    z-index: 1;
}

.knapsack-label {
    position: relative;
    width: 100%;
    text-align: center;
    font-weight: 700;
    color: #1e293b;
    /* Darker for visibility */
    font-size: 0.85rem;
    margin-top: -5px;
    margin-bottom: 0px;
    z-index: 10;
    /* High z-index to ensure visibility */
}

/* Faded button style */
button.faded {
    opacity: 0.4;
    pointer-events: none;
    cursor: not-allowed;
}

button {
    transition: opacity 0.3s ease;
}
.knapsack-container {
    cursor: default;
}
.processing-panel {
    position: relative;   /* anchor for popup */
}