/* MNIST Digit Classifier - Main Styles */

:root {
    --accent: #0d6efd;
    --accent-soft: rgba(13, 110, 253, 0.08);
    --surface: rgba(255, 255, 255, 0.94);
    --surface-border: rgba(15, 23, 42, 0.08);
    --text-muted: #5b6472;
}

/* ------------ General Styles ------------ */
body {
    font-family: 'Segoe UI', -apple-system, BlinkMacSystemFont, sans-serif;
    background:
        radial-gradient(circle at top left, rgba(13, 110, 253, 0.12), transparent 30%),
        linear-gradient(180deg, #f6f9ff 0%, #f8f9fa 45%, #eef3f9 100%);
    color: #212529;
    min-height: 100vh;
}

/* Navbar customization */
.navbar {
    backdrop-filter: blur(12px);
}

.navbar-brand {
    font-weight: 600;
    letter-spacing: -0.5px;
}

/* Card styling */
.card {
    border: none;
    border-radius: 12px;
    transition: all 0.3s ease;
    background: var(--surface);
}

.card-header {
    border-bottom: 1px solid var(--surface-border);
    padding: 1rem 1.5rem;
    border-radius: 12px 12px 0 0 !important;
}

.control-card,
.info-card {
    border: 1px solid var(--surface-border);
    box-shadow: 0 20px 50px rgba(15, 23, 42, 0.08);
}

.eyebrow {
    display: inline-block;
    margin-bottom: 0.75rem;
    color: var(--accent);
    font-size: 0.8rem;
    font-weight: 700;
    letter-spacing: 0.08em;
    text-transform: uppercase;
}

.hero-copy {
    max-width: 680px;
}

.hero-title {
    font-size: clamp(2rem, 3vw, 2.75rem);
    line-height: 1.05;
    margin-bottom: 0.75rem;
    font-weight: 700;
    letter-spacing: -0.04em;
}

.hero-subtitle,
.pane-header p,
.info-lead,
.info-copy,
.workflow-step p {
    color: var(--text-muted);
    line-height: 1.65;
    margin-bottom: 0;
}

.pane-header {
    max-width: 700px;
    margin-bottom: 1.5rem;
}

.pane-header h3,
.info-title,
.info-section-title,
.workflow-step h3 {
    font-weight: 700;
    letter-spacing: -0.03em;
}

/* ------------ Upload Section ------------ */
.upload-area {
    border: 2px dashed #dee2e6;
    border-radius: 18px;
    padding: 3rem 1rem;
    text-align: center;
    cursor: pointer;
    transition: all 0.2s ease-in-out;
    background: linear-gradient(180deg, rgba(255, 255, 255, 0.95), rgba(13, 110, 253, 0.03));
    max-width: 500px;
    margin: 0 auto;
}

.upload-area:hover, .upload-area.dragover {
    border-color: #0d6efd;
    background-color: rgba(13, 110, 253, 0.05);
}

.upload-icon {
    margin-bottom: 1rem;
    color: #6c757d;
}

.upload-text p {
    margin-bottom: 0.25rem;
}

.upload-area:hover .upload-icon,
.upload-area.dragover .upload-icon {
    color: #0d6efd;
}

/* ------------ Drawing Canvas ------------ */
.drawing-container {
    text-align: center;
    max-width: 500px;
    margin: 0 auto;
}

.drawing-stage {
    padding: 1.25rem;
    border-radius: 24px;
    background:
        linear-gradient(135deg, rgba(13, 110, 253, 0.08), rgba(13, 110, 253, 0.02)),
        #f7fbff;
    border: 1px solid rgba(13, 110, 253, 0.14);
}

.drawing-canvas {
    background-color: white;
    border-radius: 18px;
    border: 1px solid rgba(13, 110, 253, 0.18);
    touch-action: none;
    cursor: crosshair;
    box-shadow: 0 18px 30px rgba(13, 110, 253, 0.08);
}

.quick-tip-row {
    display: flex;
    justify-content: center;
    gap: 0.75rem;
    flex-wrap: wrap;
    margin-top: 1rem;
}

.tip-pill {
    padding: 0.45rem 0.8rem;
    border-radius: 999px;
    background: rgba(13, 110, 253, 0.1);
    color: #0a58ca;
    font-size: 0.85rem;
    font-weight: 600;
}

/* ------------ Image Previews ------------ */
.image-preview-container, .processed-preview-container {
    margin: 0 auto;
    border-radius: 8px;
    overflow: hidden;
    border: 1px solid #dee2e6;
    background-color: white;
    display: flex;
    align-items: center;
    justify-content: center;
}

.image-preview-container {
    width: 150px;
    height: 150px;
}

.processed-preview-container {
    width: 140px;
    height: 140px;
}

.original-preview {
    max-width: 100%;
    max-height: 100%;
}

.processed-preview {
    width: 140px;
    height: 140px;
    image-rendering: pixelated; /* Show pixelation clearly */
}

/* ------------ Prediction Display ------------ */
.top-prediction {
    font-size: 5rem;
    font-weight: bold;
    color: #0d6efd;
    margin: 0.5rem 0;
    line-height: 1;
    height: 100px;
    display: flex;
    align-items: center;
    justify-content: center;
}

.chart-container {
    height: 250px;
    position: relative;
    margin-top: 1rem;
}

/* ------------ Info Panel ------------ */
.info-card {
    position: sticky;
    top: 1.5rem;
    overflow: hidden;
}

.info-card::before {
    content: "";
    position: absolute;
    inset: 0;
    background:
        radial-gradient(circle at top right, rgba(13, 110, 253, 0.12), transparent 30%),
        linear-gradient(180deg, rgba(255, 255, 255, 0.08), transparent);
    pointer-events: none;
}

.info-card .card-body {
    position: relative;
}

.info-title {
    font-size: 1.7rem;
    margin-bottom: 0.75rem;
}

.workflow-step {
    display: grid;
    grid-template-columns: 44px 1fr;
    gap: 1rem;
    align-items: start;
    padding: 1rem 0;
    border-bottom: 1px solid rgba(15, 23, 42, 0.07);
}

.workflow-list .workflow-step:last-child {
    border-bottom: none;
}

.step-number {
    width: 44px;
    height: 44px;
    border-radius: 14px;
    display: flex;
    align-items: center;
    justify-content: center;
    background: linear-gradient(135deg, #0d6efd, #4ea1ff);
    color: #fff;
    font-weight: 700;
    box-shadow: 0 12px 24px rgba(13, 110, 253, 0.18);
}

.workflow-step h3,
.info-section-title {
    font-size: 1rem;
    margin-bottom: 0.35rem;
}

.info-divider {
    height: 1px;
    background: linear-gradient(90deg, rgba(13, 110, 253, 0.3), transparent);
    margin: 1.25rem 0;
}

.tips-list {
    padding-left: 1.2rem;
    margin-bottom: 0;
    color: var(--text-muted);
}

.tips-list li + li {
    margin-top: 0.45rem;
}

/* ------------ Loading Overlay ------------ */
.loading-overlay {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background-color: rgba(255, 255, 255, 0.8);
    display: flex;
    flex-direction: column;
    justify-content: center;
    align-items: center;
    z-index: 1050;
}

/* ------------ Responsive Adjustments ------------ */
@media (max-width: 767.98px) {
    .hero-title {
        font-size: 1.75rem;
    }

    .top-prediction {
        font-size: 4rem;
        height: 80px;
    }

    .chart-container {
        height: 200px;
    }

    .drawing-canvas {
        width: 100%;
        max-width: 280px;
        height: auto;
    }

    .drawing-stage {
        padding: 0.85rem;
    }

    .info-card {
        position: static;
    }
}

/* Animation for results */
@keyframes fadeIn {
    from { opacity: 0; transform: translateY(10px); }
    to { opacity: 1; transform: translateY(0); }
}

#results-section:not(.d-none) {
    animation: fadeIn 0.5s ease-out forwards;
}

/* Navigation pills customization */
.nav-pills .nav-link {
    border-radius: 6px;
    padding: 0.75rem 1.5rem;
    font-weight: 500;
    color: #37516f;
    background-color: rgba(13, 110, 253, 0.05);
}

.nav-pills .nav-link.active {
    background: linear-gradient(135deg, #0d6efd, #4f9dff);
    box-shadow: 0 10px 18px rgba(13, 110, 253, 0.16);
}

/* Bootstrap icons (for tab icons) */
@import url("https://cdn.jsdelivr.net/npm/bootstrap-icons@1.10.0/font/bootstrap-icons.css");