/* ===================================================
   QuizSense Premium UI Styles
   Enhances Bootstrap 5 with refined, premium feel
   =================================================== */

:root {
    --qs-primary: #0d6efd;
    --qs-primary-dark: #0a58ca;
    --qs-primary-light: #dce9ff;
    --qs-surface: #ffffff;
    --qs-bg: #f8f9fa;
    --qs-border: #e9ecef;
    --qs-text: #212529;
    --qs-text-muted: #6c757d;
    --qs-radius: 0.75rem;
    --qs-radius-lg: 1rem;
    --qs-radius-sm: 0.5rem;
    --qs-shadow-sm: 0 1px 3px rgba(0,0,0,0.06), 0 1px 2px rgba(0,0,0,0.04);
    --qs-shadow: 0 4px 12px rgba(0,0,0,0.07), 0 2px 4px rgba(0,0,0,0.04);
    --qs-shadow-lg: 0 8px 24px rgba(0,0,0,0.1), 0 4px 8px rgba(0,0,0,0.06);
    --qs-transition: 0.2s cubic-bezier(0.4, 0, 0.2, 1);
    --qs-success: #198754;
    --qs-success-light: #d1e7dd;
    --qs-danger: #dc3545;
    --qs-danger-light: #f8d7da;
    --qs-warning: #ffc107;
    --qs-warning-light: #fff3cd;
    --qs-info: #0dcaf0;
    --qs-info-light: #cff4fc;
}

:focus-visible {
    outline: 2px solid var(--qs-primary);
    outline-offset: 2px;
}

@keyframes chipPop {
    0% { transform: scale(1); }
    50% { transform: scale(1.2); }
    100% { transform: scale(1); }
}
.q-chip.answered {
    animation: chipPop 0.3s ease;
}

* {
    box-sizing: border-box;
}

::selection {
    background: var(--qs-primary-light);
    color: var(--qs-primary-dark);
}

body {
    background-color: var(--qs-bg);
    font-family: 'Inter', system-ui, -apple-system, sans-serif;
    color: var(--qs-text);
    line-height: 1.6;
    -webkit-font-smoothing: antialiased;
}

/* ---------------------------------------------------
   Typography
   --------------------------------------------------- */

h1, h2, h3, h4, h5, h6 {
    font-weight: 600;
    line-height: 1.3;
    color: var(--qs-text);
}

.display-5 {
    font-size: 2.25rem;
}

.lead {
    font-size: 1.1rem;
    color: var(--qs-text-muted);
}

/* ---------------------------------------------------
   Cards - Premium feel with subtle borders & shadows
   --------------------------------------------------- */

.card {
    border: 1px solid var(--qs-border);
    border-radius: var(--qs-radius-lg);
    box-shadow: var(--qs-shadow);
    background: var(--qs-surface);
    transition: box-shadow var(--qs-transition), transform var(--qs-transition);
}

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

.card-header {
    background: var(--qs-surface);
    border-bottom: 1px solid var(--qs-border);
    padding: 1rem 1.25rem;
    font-weight: 600;
    font-size: 0.95rem;
}

.card-body {
    padding: 1.25rem;
}

/* ---------------------------------------------------
   Buttons - Refined, consistent styling
   --------------------------------------------------- */

.btn {
    font-weight: 500;
    border-radius: var(--qs-radius);
    padding: 0.5rem 1.25rem;
    font-size: 0.9rem;
    border: none;
    transition: all var(--qs-transition);
    display: inline-flex;
    align-items: center;
    justify-content: center;
    text-align: center;
    gap: 0.375rem;
    white-space: nowrap;
}

.d-grid .btn {
    justify-content: center;
    text-align: center;
}

.btn:focus {
    box-shadow: 0 0 0 3px rgba(13, 110, 253, 0.15);
}

.btn:active {
    transform: scale(0.98);
}

.btn-sm {
    padding: 0.35rem 0.85rem;
    font-size: 0.825rem;
}

.btn-lg {
    padding: 0.65rem 1.5rem;
    font-size: 1rem;
    border-radius: var(--qs-radius-lg);
}

/* Primary button - gradient */
.btn-primary {
    background: linear-gradient(135deg, var(--qs-primary) 0%, var(--qs-primary-dark) 100%);
    border: none;
    color: #fff;
    box-shadow: 0 2px 8px rgba(13, 110, 253, 0.3);
}

.btn-primary:hover {
    background: linear-gradient(135deg, var(--qs-primary-dark) 0%, #084298 100%);
    color: #fff;
    box-shadow: 0 4px 12px rgba(13, 110, 253, 0.4);
    transform: translateY(-1px);
}

/* Outline buttons */
.btn-outline-primary {
    border: 1.5px solid var(--qs-primary);
    color: var(--qs-primary);
    background: transparent;
}

.btn-outline-primary:hover {
    background: var(--qs-primary-light);
    border-color: var(--qs-primary);
    color: var(--qs-primary-dark);
}

.btn-outline-secondary {
    border: 1.5px solid var(--qs-border);
    color: var(--qs-text-muted);
    background: transparent;
}

.btn-outline-secondary:hover {
    background: var(--qs-bg);
    border-color: #adb5bd;
    color: var(--qs-text);
}

/* Success, danger, warning outline variants */
.btn-outline-success {
    border: 1.5px solid #198754;
    color: #198754;
}

.btn-outline-success:hover {
    background: #d1e7dd;
    border-color: #198754;
    color: #146c43;
}

.btn-outline-danger {
    border: 1.5px solid #dc3545;
    color: #dc3545;
}

.btn-outline-danger:hover {
    background: #f8d7da;
    border-color: #dc3545;
    color: #b02a37;
}

/* Soft background buttons */
.btn-success {
    background: linear-gradient(135deg, #198754 0%, #146c43 100%);
    border: none;
    color: #fff;
    box-shadow: 0 2px 8px rgba(25, 135, 84, 0.25);
}

.btn-success:hover {
    background: linear-gradient(135deg, #146c43 0%, #0f5132 100%);
    color: #fff;
    box-shadow: 0 4px 12px rgba(25, 135, 84, 0.35);
    transform: translateY(-1px);
}

/* Icon button enhancement */
.btn i {
    font-size: 1em;
}

/* ---------------------------------------------------
   Form Controls - Premium inputs
   --------------------------------------------------- */

.form-control,
.form-select {
    border: 1.5px solid var(--qs-border);
    border-radius: var(--qs-radius);
    padding: 0.55rem 0.85rem;
    font-size: 0.9rem;
    transition: border-color var(--qs-transition), box-shadow var(--qs-transition);
    background: var(--qs-surface);
}

.form-control:focus,
.form-select:focus {
    border-color: var(--qs-primary);
    box-shadow: 0 0 0 3px rgba(13, 110, 253, 0.1);
    outline: none;
}

.form-label {
    font-weight: 500;
    font-size: 0.875rem;
    color: var(--qs-text);
    margin-bottom: 0.35rem;
}

/* ---------------------------------------------------
   Badges & Chips
   --------------------------------------------------- */

.badge {
    font-weight: 500;
    font-size: 0.75rem;
    padding: 0.35em 0.65em;
    border-radius: var(--qs-radius-sm);
}

.badge.bg-primary {
    background: var(--qs-primary) !important;
}

.badge.bg-secondary {
    background: #6c757d !important;
}

/* Choice chips / answer option buttons */
.choice-chip {
    display: flex;
    align-items: center;
    gap: 0.75rem;
    padding: 0.85rem 1.1rem;
    border: 1.5px solid var(--qs-border);
    border-radius: var(--qs-radius);
    background: var(--qs-surface);
    cursor: pointer;
    transition: all var(--qs-transition);
    font-size: 0.95rem;
    text-align: left;
    width: 100%;
}

.choice-chip:hover {
    border-color: var(--qs-primary);
    background: var(--qs-primary-light);
    transform: translateX(4px);
}

.choice-chip.selected {
    border-color: var(--qs-primary);
    background: var(--qs-primary-light);
    box-shadow: 0 0 0 3px rgba(13, 110, 253, 0.12);
}

.choice-chip .choice-letter {
    display: flex;
    align-items: center;
    justify-content: center;
    width: 32px;
    height: 32px;
    border-radius: 50%;
    background: var(--qs-bg);
    font-weight: 600;
    font-size: 0.85rem;
    color: var(--qs-text-muted);
    flex-shrink: 0;
    transition: all var(--qs-transition);
}

.choice-chip.selected .choice-letter {
    background: var(--qs-primary);
    color: #fff;
}

/* Question navigation chips */
.q-chip {
    width: 36px;
    height: 36px;
    border-radius: 50%;
    font-size: 0.825rem;
    font-weight: 500;
    display: inline-flex;
    align-items: center;
    justify-content: center;
    border: 1.5px solid var(--qs-border);
    background: var(--qs-surface);
    cursor: pointer;
    transition: all var(--qs-transition);
}

.q-chip:hover {
    border-color: var(--qs-primary);
    background: var(--qs-primary-light);
}

.q-chip.active {
    background: var(--qs-primary);
    border-color: var(--qs-primary);
    color: #fff;
}

.q-chip.answered {
    background: #d1e7dd;
    border-color: #198754;
    color: #146c43;
}

.q-chip.current {
    background: var(--qs-primary-light);
    border-color: var(--qs-primary);
    color: var(--qs-primary-dark);
}

/* ---------------------------------------------------
   Upload Zone
   --------------------------------------------------- */

.upload-zone {
    border: 2px dashed var(--qs-primary) !important;
    border-radius: var(--qs-radius-lg);
    background: linear-gradient(135deg, #f0f6ff 0%, #f8fbff 100%);
    padding: 1.5rem 1.25rem;
    text-align: center;
    cursor: pointer;
    transition: all var(--qs-transition);
}

.upload-zone:hover {
    background: linear-gradient(135deg, #dce9ff 0%, #eef4ff 100%);
    border-color: var(--qs-primary-dark) !important;
    transform: translateY(-2px);
    box-shadow: 0 4px 16px rgba(13, 110, 253, 0.12);
}

.upload-zone.drag-over {
    background: linear-gradient(135deg, #dce9ff 0%, #c8deff 100%);
    border-color: var(--qs-primary-dark) !important;
    transform: scale(1.01);
}

.upload-zone-icon {
    font-size: 2rem;
    color: var(--qs-primary);
    margin-bottom: 0.5rem;
    animation: gentlePulse 3s ease-in-out infinite;
}

@keyframes gentlePulse {
    0%, 100% { transform: scale(1); }
    50% { transform: scale(1.05); }
}

.upload-zone-label {
    font-weight: 600;
    font-size: 0.95rem;
    color: var(--qs-primary);
}

.upload-zone-hint {
    font-size: 0.8rem;
    color: var(--qs-text-muted);
}

/* ---------------------------------------------------
   Progress bars
   --------------------------------------------------- */

.progress {
    height: 8px;
    border-radius: 999px;
    background: var(--qs-border);
    overflow: hidden;
}

.progress-bar {
    border-radius: 999px;
    transition: width 0.4s ease;
}

/* ---------------------------------------------------
   Stats Cards (score display)
   --------------------------------------------------- */

.stat-card {
    text-align: center;
    padding: 1.25rem 1rem;
    border-radius: var(--qs-radius-lg);
    background: var(--qs-surface);
    border: 1px solid var(--qs-border);
    transition: all var(--qs-transition);
}

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

.stat-value {
    font-size: 1.5rem !important;
    font-weight: 700;
    line-height: 1.2;
    white-space: nowrap !important;
    overflow: hidden;
    text-overflow: ellipsis;
}

.stat-value.text-success { color: #198754; }
.stat-value.text-warning { color: #ffc107; }
.stat-value.text-danger { color: #dc3545; }
.stat-value.text-primary { color: var(--qs-primary); }

.stat-label {
    font-size: 0.8rem;
    color: var(--qs-text-muted);
    font-weight: 500;
    text-transform: uppercase;
    letter-spacing: 0.05em;
    margin-top: 0.25rem;
}

/* ---------------------------------------------------
   Navigation & Sidebar
   --------------------------------------------------- */

.quiz-nav-bar {
    position: sticky;
    top: 1rem;
    z-index: 100;
    background: rgba(255, 255, 255, 0.95);
    backdrop-filter: blur(8px);
    border-radius: var(--qs-radius-lg);
    padding: 0.85rem 1.25rem;
    box-shadow: var(--qs-shadow);
    border: 1px solid var(--qs-border);
}

.sticky-bottom-bar {
    position: sticky;
    bottom: 1rem;
    z-index: 100;
    background: rgba(255, 255, 255, 0.95);
    backdrop-filter: blur(8px);
    border-radius: var(--qs-radius-lg);
    padding: 0.85rem 1.25rem;
    box-shadow: var(--qs-shadow-lg);
    border: 1px solid var(--qs-border);
}

/* ---------------------------------------------------
   Question Cards
   --------------------------------------------------- */

.question-card {
    border: 1px solid var(--qs-border);
    border-radius: var(--qs-radius-lg);
    overflow: hidden;
    transition: all var(--qs-transition);
}

.question-card:hover {
    box-shadow: var(--qs-shadow);
}

.question-card .card-header {
    background: linear-gradient(135deg, #f8f9fa 0%, #ffffff 100%);
}

/* Correct/incorrect state borders */
.question-card.correct {
    border-left: 4px solid #198754;
}

.question-card.incorrect {
    border-left: 4px solid #dc3545;
}

/* ---------------------------------------------------
   Alerts
   --------------------------------------------------- */

.alert {
    animation: slideDown 0.3s ease both;
}

.alert {
    border: 1px solid transparent;
    border-radius: var(--qs-radius);
    padding: 1rem 1.25rem;
    font-size: 0.9rem;
}

.alert-info {
    background: #cfe2ff;
    border-color: #b6d4fe;
    color: #084298;
}

.alert-warning {
    background: #fff3cd;
    border-color: #ffecb5;
    color: #664d03;
}

.alert-danger {
    background: #f8d7da;
    border-color: #f5c2c7;
    color: #842029;
}

.alert-success {
    background: #d1e7dd;
    border-color: #badbcc;
    color: #146c43;
}

/* ---------------------------------------------------
   Tables
   --------------------------------------------------- */

.table {
    font-size: 0.9rem;
}

.table thead th {
    font-weight: 600;
    font-size: 0.8rem;
    text-transform: uppercase;
    letter-spacing: 0.04em;
    color: var(--qs-text-muted);
    border-bottom: 2px solid var(--qs-border);
    padding: 0.75rem 1rem;
}

.table tbody td {
    padding: 0.85rem 1rem;
    vertical-align: middle;
}

.table tbody tr {
    transition: background var(--qs-transition);
}

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

/* ---------------------------------------------------
   How It Works Section
   --------------------------------------------------- */

.step-card {
    text-align: center;
    padding: 1.75rem 1.25rem;
    border-radius: var(--qs-radius-lg);
    background: var(--qs-surface);
    border: 1px solid var(--qs-border);
    transition: all var(--qs-transition);
    height: 100%;
    animation: fadeInUp 0.5s ease both;
}
.step-card:nth-child(1) { animation-delay: 0.1s; }
.step-card:nth-child(2) { animation-delay: 0.2s; }
.step-card:nth-child(3) { animation-delay: 0.3s; }
.step-card:nth-child(4) { animation-delay: 0.4s; }

.step-card:hover {
    transform: translateY(-4px);
    box-shadow: var(--qs-shadow-lg);
    border-color: var(--qs-primary-light);
}

.step-card-icon {
    width: 56px;
    height: 56px;
    border-radius: 50%;
    background: linear-gradient(135deg, var(--qs-primary-light) 0%, #e7f1ff 100%);
    display: flex;
    align-items: center;
    justify-content: center;
    margin: 0 auto 1rem;
    font-size: 1.5rem;
    color: var(--qs-primary);
}

.step-card-title {
    font-weight: 600;
    font-size: 1rem;
    margin-bottom: 0.5rem;
}

.step-card-desc {
    font-size: 0.85rem;
    color: var(--qs-text-muted);
    margin: 0;
}

/* ---------------------------------------------------
   Back to top button
   --------------------------------------------------- */

.back-to-top {
    position: fixed !important;
    bottom: 1.5rem;
    right: 1.5rem;
    width: 40px;
    height: 40px;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    background: linear-gradient(135deg, var(--qs-primary) 0%, var(--qs-primary-dark) 100%);
    color: #fff;
    border: none;
    box-shadow: var(--qs-shadow);
    transition: all var(--qs-transition);
    opacity: 0;
    pointer-events: none;
    z-index: 1050;
}

.back-to-top.visible {
    opacity: 1;
    pointer-events: auto;
}

.back-to-top:hover {
    transform: translateY(-2px);
    box-shadow: var(--qs-shadow-lg);
    background: linear-gradient(135deg, var(--qs-primary-dark) 0%, #084298 100%);
}

/* ---------------------------------------------------
   Utility classes
   --------------------------------------------------- */



.section-title {
    font-size: 1.1rem;
    font-weight: 600;
    color: var(--qs-text);
    margin-bottom: 1rem;
}

.icon-box {
    width: 48px;
    height: 48px;
    border-radius: var(--qs-radius);
    background: linear-gradient(135deg, var(--qs-primary-light) 0%, #e7f1ff 100%);
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 1.25rem;
    color: var(--qs-primary);
}

/* ---------------------------------------------------
   Footer
   --------------------------------------------------- */

.footer {
    background: #1a1d21;
    color: #8b949e;
    font-size: 0.85rem;
}

.footer a {
    color: #c6c9ce;
    text-decoration: none;
    transition: color var(--qs-transition);
}

.footer a:hover {
    color: #fff;
}

/* ---------------------------------------------------
   Responsive adjustments
   --------------------------------------------------- */

@media (max-width: 768px) {
    .display-5 {
        font-size: 1.75rem;
    }

    .card-body {
        padding: 1rem;
    }

    .btn-lg {
        padding: 0.55rem 1.25rem;
        font-size: 0.95rem;
    }

    .upload-zone {
        padding: 1.25rem 1rem;
    }
}

/* ---------------------------------------------------
   Chart.js custom styling
   --------------------------------------------------- */

canvas {
    border-radius: var(--qs-radius);
}

/* ---------------------------------------------------
   Loading/Generating spinner
   --------------------------------------------------- */

.spinner-wrap {
    padding: 3rem 2rem;
    text-align: center;
}

.spinner-icon {
    font-size: 3.5rem;
    color: var(--qs-primary);
    animation: pulse 1.5s ease-in-out infinite;
}

@keyframes pulse {
    0%, 100% { opacity: 1; transform: scale(1); }
    50% { opacity: 0.6; transform: scale(0.95); }
}

/* Animated gradient bar */
.progress-bar-animated-gradient {
    background: linear-gradient(
        90deg,
        var(--qs-primary) 0%,
        var(--qs-primary-dark) 50%,
        var(--qs-primary) 100%
    );
    background-size: 200% 100%;
    animation: shimmer 1.5s linear infinite;
}

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

@keyframes shimmer {
    0% { background-position: 200% 0; }
    100% { background-position: -200% 0; }
}

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

@media (prefers-reduced-motion: reduce) {
    *, *::before, *::after {
        animation-duration: 0.01ms !important;
        animation-iteration-count: 1 !important;
        transition-duration: 0.01ms !important;
    }
}