/* ==================== CSS Variables ==================== */
:root {
    --primary: #667eea;
    --primary-dark: #5568d3;
    --secondary: #764ba2;
    --accent: #f093fb;
    --success: #10b981;
    --warning: #f59e0b;
    --error: #ef4444;
    --info: #3b82f6;

    --bg-gradient: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    --bg-light: #f8f9fa;
    --bg-white: #ffffff;
    --bg-dark: #1a1a2e;

    --text-primary: #1f2937;
    --text-secondary: #6b7280;
    --text-light: #9ca3af;

    --border-color: #e5e7eb;
    --border-radius: 12px;
    --border-radius-lg: 16px;
    --border-radius-sm: 8px;

    --shadow-sm: 0 1px 3px rgba(0, 0, 0, 0.1);
    --shadow-md: 0 4px 6px rgba(0, 0, 0, 0.1);
    --shadow-lg: 0 10px 15px rgba(0, 0, 0, 0.1);
    --shadow-xl: 0 20px 25px rgba(0, 0, 0, 0.15);

    --transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
}

/* ==================== Reset & Base Styles ==================== */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

body {
    font-family: 'Inter', 'Segoe UI', -apple-system, BlinkMacSystemFont, sans-serif;
    background: var(--bg-gradient);
    color: var(--text-primary);
    min-height: 100vh;
    padding: 20px;
    line-height: 1.6;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
}

/* ==================== Container ==================== */
.container {
    max-width: 1600px;
    margin: 0 auto;
    background: var(--bg-white);
    border-radius: var(--border-radius-lg);
    box-shadow: var(--shadow-xl);
    overflow: hidden;
    animation: fadeIn 0.5s ease-out;
}

@keyframes fadeIn {
    from {
        opacity: 0;
        transform: translateY(20px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

/* ==================== Header ==================== */
header {
    background: var(--bg-gradient);
    color: white;
    padding: 40px 30px;
    text-align: center;
    position: relative;
    overflow: hidden;
}

header::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: url('data:image/svg+xml,<svg width="100" height="100" xmlns="http://www.w3.org/2000/svg"><defs><pattern id="grid" width="20" height="20" patternUnits="userSpaceOnUse"><circle cx="10" cy="10" r="1" fill="white" opacity="0.1"/></pattern></defs><rect width="100" height="100" fill="url(%23grid)"/></svg>');
    opacity: 0.3;
}

header h1 {
    font-size: 3em;
    margin-bottom: 10px;
    font-weight: 800;
    position: relative;
    letter-spacing: -1px;
    text-shadow: 0 2px 10px rgba(0, 0, 0, 0.2);
}

.subtitle {
    font-size: 1.2em;
    opacity: 0.95;
    position: relative;
    font-weight: 400;
}

/* ==================== Tabs ==================== */
.tabs {
    display: flex;
    background: var(--bg-light);
    border-bottom: 2px solid var(--border-color);
    position: sticky;
    top: 0;
    z-index: 100;
    backdrop-filter: blur(10px);
}

.tab-button {
    flex: 1;
    padding: 18px 30px;
    background: transparent;
    border: none;
    cursor: pointer;
    font-size: 1.1em;
    font-weight: 600;
    color: var(--text-secondary);
    transition: var(--transition);
    position: relative;
    border-bottom: 3px solid transparent;
}

.tab-button::before {
    content: '';
    position: absolute;
    bottom: 0;
    left: 50%;
    width: 0;
    height: 3px;
    background: var(--bg-gradient);
    transition: var(--transition);
    transform: translateX(-50%);
}

.tab-button:hover {
    background: rgba(102, 126, 234, 0.05);
    color: var(--primary);
}

.tab-button.active {
    color: var(--primary);
    background: var(--bg-white);
}

.tab-button.active::before {
    width: 100%;
}

/* ==================== Tab Content ==================== */
.tab-content {
    display: none;
    padding: 30px;
    animation: slideIn 0.3s ease-out;
}

.tab-content.active {
    display: block;
}

@keyframes slideIn {
    from {
        opacity: 0;
        transform: translateX(-10px);
    }
    to {
        opacity: 1;
        transform: translateX(0);
    }
}

/* ==================== Cards ==================== */
.card {
    background: var(--bg-white);
    border-radius: var(--border-radius);
    padding: 30px;
    margin-bottom: 25px;
    box-shadow: var(--shadow-md);
    border: 1px solid var(--border-color);
    transition: var(--transition);
}

.card:hover {
    box-shadow: var(--shadow-lg);
    transform: translateY(-2px);
}

.card h2 {
    color: var(--primary);
    margin-bottom: 20px;
    font-size: 1.8em;
    font-weight: 700;
    display: flex;
    align-items: center;
    gap: 12px;
}

.card h2::before {
    content: '';
    width: 4px;
    height: 28px;
    background: var(--bg-gradient);
    border-radius: 2px;
}

.card h3 {
    color: var(--text-primary);
    margin-bottom: 15px;
    font-size: 1.3em;
    font-weight: 600;
}

/* ==================== Info Blocks ==================== */
.info {
    background: linear-gradient(135deg, #e0f2fe 0%, #dbeafe 100%);
    border-left: 4px solid var(--info);
    padding: 15px 20px;
    margin: 15px 0;
    border-radius: var(--border-radius-sm);
    font-size: 0.95em;
    color: #0c4a6e;
    display: flex;
    align-items: center;
    gap: 12px;
}

.info::before {
    content: 'ℹ️';
    font-size: 1.2em;
}

/* ==================== Controls ==================== */
.controls {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
    gap: 20px;
    margin-bottom: 25px;
}

.control-group {
    display: flex;
    flex-direction: column;
    gap: 8px;
}

.control-group label {
    font-weight: 600;
    color: var(--text-primary);
    font-size: 0.95em;
    display: flex;
    align-items: center;
    gap: 6px;
}

.control-group input,
.control-group select {
    padding: 12px 16px;
    border: 2px solid var(--border-color);
    border-radius: var(--border-radius-sm);
    font-size: 1em;
    font-family: inherit;
    transition: var(--transition);
    background: var(--bg-white);
    color: var(--text-primary);
}

.control-group input:focus,
.control-group select:focus {
    outline: none;
    border-color: var(--primary);
    box-shadow: 0 0 0 3px rgba(102, 126, 234, 0.1);
}

.control-group input:hover,
.control-group select:hover {
    border-color: var(--primary-dark);
}

/* ==================== Buttons ==================== */
.btn {
    padding: 14px 28px;
    border: none;
    border-radius: var(--border-radius-sm);
    font-size: 1em;
    font-weight: 600;
    cursor: pointer;
    transition: var(--transition);
    font-family: inherit;
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: 8px;
    position: relative;
    overflow: hidden;
}

.btn::before {
    content: '';
    position: absolute;
    top: 50%;
    left: 50%;
    width: 0;
    height: 0;
    border-radius: 50%;
    background: rgba(255, 255, 255, 0.3);
    transform: translate(-50%, -50%);
    transition: width 0.6s, height 0.6s;
}

.btn:active::before {
    width: 300px;
    height: 300px;
}

.btn-primary {
    background: var(--bg-gradient);
    color: white;
    box-shadow: var(--shadow-sm);
}

.btn-primary:hover {
    transform: translateY(-2px);
    box-shadow: var(--shadow-md);
}

.btn-primary:active {
    transform: translateY(0);
}

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

.btn-secondary:hover {
    background: var(--text-primary);
    transform: translateY(-2px);
    box-shadow: var(--shadow-sm);
}

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

.btn-danger:hover {
    background: #dc2626;
    transform: translateY(-2px);
    box-shadow: var(--shadow-sm);
}

.button-group {
    display: flex;
    flex-wrap: wrap;
    gap: 12px;
    margin-top: 20px;
}

/* ==================== Progress Bar ==================== */
.progress-container {
    margin: 25px 0;
    background: var(--bg-light);
    border-radius: var(--border-radius);
    overflow: hidden;
    padding: 20px;
    box-shadow: var(--shadow-sm);
    border: 1px solid var(--border-color);
}

.progress-bar {
    height: 32px;
    background: var(--bg-gradient);
    border-radius: var(--border-radius-sm);
    transition: width 0.3s ease;
    width: 0%;
    box-shadow: 0 2px 8px rgba(102, 126, 234, 0.3);
    position: relative;
    overflow: hidden;
}

.progress-bar::after {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: linear-gradient(90deg, transparent, rgba(255, 255, 255, 0.3), transparent);
    animation: shimmer 2s infinite;
}

@keyframes shimmer {
    0% {
        transform: translateX(-100%);
    }
    100% {
        transform: translateX(100%);
    }
}

#progress-text {
    text-align: center;
    margin-top: 12px;
    font-weight: 600;
    color: var(--text-primary);
    font-size: 0.95em;
}

/* ==================== Output Sections ==================== */
.output {
    background: var(--bg-light);
    border-radius: var(--border-radius);
    padding: 25px;
    margin-top: 20px;
    border: 1px solid var(--border-color);
}

.output.hidden {
    display: none;
}

/* Stats Grid */
.stats-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(150px, 1fr));
    gap: 15px;
    margin-bottom: 20px;
}

.stat-card {
    background: var(--bg-white);
    padding: 20px;
    border-radius: var(--border-radius-sm);
    text-align: center;
    box-shadow: var(--shadow-sm);
    border: 1px solid var(--border-color);
    transition: var(--transition);
}

.stat-card:hover {
    transform: translateY(-3px);
    box-shadow: var(--shadow-md);
}

.stat-label {
    font-size: 0.85em;
    color: var(--text-secondary);
    text-transform: uppercase;
    letter-spacing: 0.5px;
    font-weight: 600;
    margin-bottom: 8px;
}

.stat-value {
    font-size: 2em;
    font-weight: 700;
    background: var(--bg-gradient);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.distance-info {
    background: var(--bg-white);
    padding: 15px;
    border-radius: var(--border-radius-sm);
    border: 1px solid var(--border-color);
    font-size: 0.95em;
}

/* ==================== Tables ==================== */
.table-wrapper {
    overflow-x: auto;
    border-radius: var(--border-radius-sm);
    box-shadow: var(--shadow-sm);
    margin-top: 15px;
}

.data-table {
    width: 100%;
    border-collapse: separate;
    border-spacing: 0;
    background: var(--bg-white);
    border: 1px solid var(--border-color);
    border-radius: var(--border-radius-sm);
    overflow: hidden;
}

.data-table thead {
    background: var(--bg-gradient);
    color: white;
}

.data-table th,
.data-table td {
    padding: 14px 18px;
    text-align: left;
}

.data-table th {
    font-weight: 600;
    text-transform: uppercase;
    font-size: 0.85em;
    letter-spacing: 0.5px;
}

.data-table tbody tr {
    transition: var(--transition);
    border-bottom: 1px solid var(--border-color);
}

.data-table tbody tr:hover {
    background: var(--bg-light);
}

.data-table tbody tr:last-child {
    border-bottom: none;
}

.more-rows {
    text-align: center;
    font-style: italic;
    color: var(--text-secondary);
    background: var(--bg-light);
}

/* Distance Matrix */
.distance-matrix {
    font-size: 0.85em;
}

.distance-matrix td {
    text-align: center;
    padding: 8px 12px;
}

.distance-matrix th {
    text-align: center;
    padding: 8px 12px;
}

.distance-matrix .diagonal {
    background: var(--bg-light);
    font-weight: 600;
    color: var(--text-secondary);
}

/* Matrix Grid View */
.matrix-grid {
    font-size: 0.75em;
}

.matrix-grid td {
    text-align: center;
    padding: 6px 10px;
    font-family: 'Courier New', monospace;
}

.matrix-grid th {
    text-align: center;
    padding: 6px 10px;
    font-size: 0.9em;
}

.matrix-grid .diagonal {
    background: #fff3cd;
    font-weight: 600;
}

/* ==================== Results Grid ==================== */
.results-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(500px, 1fr));
    gap: 25px;
    margin-top: 25px;
}

.result-box {
    background: var(--bg-light);
    border-radius: var(--border-radius);
    padding: 25px;
    box-shadow: var(--shadow-md);
    border: 1px solid var(--border-color);
    transition: var(--transition);
}

.result-box:hover {
    box-shadow: var(--shadow-lg);
}

.result-box h3 {
    color: var(--primary);
    margin-bottom: 15px;
    font-size: 1.2em;
    font-weight: 600;
}

#tsne-plot,
#cost-plot,
#p-matrix-plot,
#q-matrix-plot {
    min-height: 400px;
    background: var(--bg-white);
    border-radius: var(--border-radius-sm);
    margin-top: 10px;
}

#coords-table {
    max-height: 400px;
    overflow-y: auto;
}

/* ==================== Upload Section ==================== */
.upload-section {
    background: var(--bg-light);
    border-radius: var(--border-radius);
    padding: 25px;
    margin-bottom: 25px;
    border: 2px dashed var(--border-color);
    transition: var(--transition);
}

.upload-section:hover {
    border-color: var(--primary);
    background: rgba(102, 126, 234, 0.02);
}

.upload-section h3 {
    color: var(--primary);
    margin-bottom: 15px;
    font-size: 1.3em;
}

input[type="file"] {
    display: none;
}

/* Dataset List */
.upload-list {
    background: var(--bg-light);
    border-radius: var(--border-radius);
    padding: 25px;
    border: 1px solid var(--border-color);
}

.dataset-list {
    list-style: none;
}

.dataset-item {
    padding: 15px 20px;
    margin-bottom: 12px;
    background: var(--bg-white);
    border-radius: var(--border-radius-sm);
    border-left: 4px solid var(--primary);
    font-size: 1em;
    box-shadow: var(--shadow-sm);
    display: flex;
    align-items: center;
    gap: 12px;
    transition: var(--transition);
}

.dataset-item:hover {
    transform: translateX(5px);
    box-shadow: var(--shadow-md);
}

.dataset-icon {
    font-size: 1.5em;
}

.dataset-label {
    flex: 1;
    font-weight: 500;
}

.empty-state {
    text-align: center;
    padding: 40px;
    color: var(--text-secondary);
    font-size: 1.1em;
}

/* CSV Columns Selector */
#csv-columns-list {
    background: var(--bg-white);
    padding: 20px;
    border-radius: var(--border-radius-sm);
    max-height: 250px;
    overflow-y: auto;
    border: 2px solid var(--border-color);
    margin-top: 10px;
}

.checkbox-label {
    display: block;
    padding: 12px;
    cursor: pointer;
    transition: var(--transition);
    border-radius: var(--border-radius-sm);
    font-weight: 500;
}

.checkbox-label:hover {
    background: var(--bg-light);
}

.checkbox-label input[type="checkbox"] {
    margin-right: 10px;
    cursor: pointer;
    width: 18px;
    height: 18px;
}

/* Embed Status */
.embed-status {
    margin-top: 15px;
    padding: 12px 20px;
    border-radius: var(--border-radius-sm);
    font-weight: 500;
    display: inline-block;
}

.embed-status.computing {
    background: #fef3c7;
    color: #92400e;
}

.embed-status.success {
    background: #d1fae5;
    color: #065f46;
}

.embed-status.error {
    background: #fee2e2;
    color: #991b1b;
}

/* ==================== Modal ==================== */
.modal {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: rgba(0, 0, 0, 0.8);
    backdrop-filter: blur(5px);
    display: flex;
    justify-content: center;
    align-items: center;
    z-index: 1000;
    animation: fadeIn 0.3s ease-out;
}

.modal.hidden {
    display: none;
}

.modal-content {
    background: var(--bg-white);
    border-radius: var(--border-radius-lg);
    padding: 40px;
    max-width: 900px;
    max-height: 90vh;
    overflow: auto;
    position: relative;
    box-shadow: var(--shadow-xl);
    animation: scaleIn 0.3s ease-out;
}

@keyframes scaleIn {
    from {
        opacity: 0;
        transform: scale(0.9);
    }
    to {
        opacity: 1;
        transform: scale(1);
    }
}

.modal-close {
    position: absolute;
    top: 20px;
    right: 25px;
    font-size: 2.5em;
    cursor: pointer;
    color: var(--text-secondary);
    transition: var(--transition);
    line-height: 1;
}

.modal-close:hover {
    color: var(--error);
    transform: rotate(90deg);
}

#modal-image {
    max-width: 100%;
    border-radius: var(--border-radius);
    margin-top: 20px;
    box-shadow: var(--shadow-lg);
}

/* ==================== Notifications ==================== */
#notification {
    position: fixed;
    top: -100px;
    left: 50%;
    transform: translateX(-50%);
    background: var(--bg-white);
    color: var(--text-primary);
    padding: 16px 32px;
    border-radius: var(--border-radius);
    box-shadow: var(--shadow-xl);
    z-index: 2000;
    font-weight: 600;
    min-width: 300px;
    text-align: center;
    transition: top 0.3s cubic-bezier(0.4, 0, 0.2, 1);
    border-left: 4px solid var(--primary);
}

#notification.show {
    top: 30px;
}

#notification.success {
    border-left-color: var(--success);
    background: #ecfdf5;
    color: #065f46;
}

#notification.error {
    border-left-color: var(--error);
    background: #fef2f2;
    color: #991b1b;
}

#notification.warning {
    border-left-color: var(--warning);
    background: #fffbeb;
    color: #92400e;
}

#notification.info {
    border-left-color: var(--info);
    background: #eff6ff;
    color: #1e40af;
}

/* ==================== Utility Classes ==================== */
.hidden {
    display: none !important;
}

.text-center {
    text-align: center;
}

/* ==================== Scrollbar Styling ==================== */
::-webkit-scrollbar {
    width: 12px;
    height: 12px;
}

::-webkit-scrollbar-track {
    background: var(--bg-light);
    border-radius: 10px;
}

::-webkit-scrollbar-thumb {
    background: var(--bg-gradient);
    border-radius: 10px;
    border: 2px solid var(--bg-light);
}

::-webkit-scrollbar-thumb:hover {
    background: linear-gradient(135deg, #5568d3 0%, #653a8a 100%);
}

/* ==================== Responsive Design ==================== */
@media (max-width: 1200px) {
    .results-grid {
        grid-template-columns: 1fr;
    }
}

@media (max-width: 768px) {
    body {
        padding: 10px;
    }

    .container {
        border-radius: var(--border-radius);
    }

    header {
        padding: 25px 20px;
    }

    header h1 {
        font-size: 2em;
    }

    .subtitle {
        font-size: 1em;
    }

    .tabs {
        flex-direction: column;
    }

    .tab-button {
        padding: 15px 20px;
    }

    .tab-content {
        padding: 20px;
    }

    .card {
        padding: 20px;
    }

    .controls {
        grid-template-columns: 1fr;
    }

    .results-grid {
        grid-template-columns: 1fr;
    }

    .stats-grid {
        grid-template-columns: 1fr;
    }

    .modal-content {
        margin: 20px;
        padding: 25px;
        max-width: 90%;
    }
}

@media (max-width: 480px) {
    header h1 {
        font-size: 1.6em;
    }

    .btn {
        padding: 12px 20px;
        font-size: 0.9em;
    }

    .button-group {
        flex-direction: column;
    }

    .button-group .btn {
        width: 100%;
    }
}

/* ==================== Animations ==================== */
@keyframes pulse {
    0%, 100% {
        opacity: 1;
    }
    50% {
        opacity: 0.5;
    }
}

.loading {
    animation: pulse 2s ease-in-out infinite;
}

/* ==================== Print Styles ==================== */
@media print {
    body {
        background: white;
        padding: 0;
    }

    .container {
        box-shadow: none;
    }

    header {
        background: none;
        color: black;
    }

    .tabs,
    .btn,
    .upload-section {
        display: none;
    }
}