:root {
    --bg: #FFFFFF;
    --panel: #F3F4F6;
    --text: #1F2937;
    --accent: #1B9B7E;
    --accent-strong: #168F6F;
    --danger: #f87171;
    --success: #34d399;
    --muted: #6B7280;
    --radius: 12px;
    --shadow: 0 10px 30px rgba(0, 0, 0, 0.08);
    --font: "Inter", system-ui, -apple-system, sans-serif;
}

::placeholder {
    color: #9E9E9E;
    opacity: 1;
    /* Firefox */
}

.input-field {
    width: 100%;
    background: #ffffff;
    border: 1px solid #E3E8EF;
    border-radius: var(--radius);
    padding: 10px 16px;
    color: var(--text);
    font-family: var(--font);
    transition: border-color 0.2s, box-shadow 0.2s;
}

.input-field:focus {
    border-color: #06C167;
    box-shadow: 0 0 0 2px rgba(6, 193, 103, 0.18);
    outline: none;
}

*,
*::before,
*::after {
    box-sizing: border-box;
}

body {
    margin: 0;
    min-height: 100vh;
    background: radial-gradient(circle at 20% 20%, rgba(27, 155, 126, 0.04), transparent 30%),
        radial-gradient(circle at 80% 0%, rgba(34, 201, 151, 0.04), transparent 30%),
        var(--bg);
    color: var(--text);
    font-family: var(--font);
    display: flex;
    flex-direction: column;
    justify-content: center;
    align-items: center;
    padding: 32px;
}

#app-root {
    width: min(900px, 100%);
    background: #ffffff;
    border: 1px solid rgba(0, 0, 0, 0.05);
    border-radius: var(--radius);
    box-shadow: var(--shadow);
    padding: 24px 28px;
}

.quiz-header {
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 12px;
    margin-bottom: 20px;
}

.quiz-header h1 {
    margin: 0;
    font-size: 1.4rem;
    letter-spacing: 0.3px;
}

.quiz-main {
    display: flex;
    flex-direction: column;
    gap: 16px;
}

#question-container {
    background: var(--panel);
    border-radius: var(--radius);
    padding: 18px 20px;
    border: 1px solid rgba(0, 0, 0, 0.05);
    min-height: 90px;
}

#answers-container {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: 12px;
}

.answer-btn {
    background: var(--panel);
    border: 1px solid rgba(255, 255, 255, 0.08);
    border-radius: var(--radius);
    padding: 14px 16px;
    color: var(--text);
    font-size: 1rem;
    cursor: pointer;
    transition: transform 120ms ease, box-shadow 120ms ease, border-color 120ms ease;
    text-align: left;
}

.answer-btn:hover {
    transform: translateY(-2px);
    box-shadow: 0 4px 12px rgba(27, 155, 126, 0.15);
    border-color: var(--accent);
}

.answer-btn.correct {
    border-color: var(--success);
    background: rgba(52, 211, 153, 0.12);
}

.answer-btn.incorrect {
    border-color: var(--danger);
    background: rgba(248, 113, 113, 0.12);
}

#status-container {
    display: flex;
    align-items: center;
    gap: 12px;
    color: var(--muted);
    font-size: 0.95rem;
    min-height: 28px;
}

.badge {
    display: inline-flex;
    align-items: center;
    gap: 6px;
    padding: 6px 10px;
    border-radius: 999px;
    border: 1px solid rgba(0, 0, 0, 0.08);
    background: #ffffff;
    color: var(--text);
    font-weight: 600;
}

.question-counter {
    font-size: 0.9rem;
    color: var(--muted);
    margin-bottom: 12px;
    font-weight: 500;
}

.question-timer {
    font-size: 0.9rem;
    color: var(--accent);
    font-weight: 600;
}

.results-container {
    background: var(--panel);
    border-radius: var(--radius);
    padding: 24px;
    border: 1px solid rgba(0, 0, 0, 0.05);
}

.results-container h2 {
    margin-top: 0;
    margin-bottom: 20px;
}

.results-summary {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 16px;
    margin-bottom: 24px;
    padding: 20px;
    background: #ffffff;
    border: 1px solid rgba(0, 0, 0, 0.05);
    border-radius: var(--radius);
}

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

.results-big-score {
    font-size: 3rem;
    font-weight: 700;
    color: var(--accent);
    line-height: 1;
}

.results-percentage {
    font-size: 1.5rem;
    color: var(--muted);
    margin-top: 8px;
}

.results-stats {
    text-align: center;
    color: var(--muted);
    font-size: 0.95rem;
}

.results-stats p {
    margin: 4px 0;
}

.results-review {
    margin-top: 24px;
}

.results-review h3 {
    margin-bottom: 16px;
    font-size: 1.1rem;
}

.result-question-item {
    background: #ffffff;
    border: 1px solid rgba(0, 0, 0, 0.08);
    border-radius: var(--radius);
    padding: 16px;
    margin-bottom: 12px;
}

.result-question-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 8px;
    font-size: 0.9rem;
}

.result-question-header strong {
    color: var(--text);
}

.result-question-header span {
    color: var(--muted);
}

.result-question-prompt {
    margin-bottom: 8px;
    color: var(--text);
}

.result-question-answer {
    color: var(--success);
    font-weight: 500;
}

/* Admin UI styles */
.admin-toggle-btn {
    background: #ffffff;
    border: 1px solid rgba(0, 0, 0, 0.08);
    border-radius: var(--radius);
    padding: 8px 16px;
    color: var(--text);
    cursor: pointer;
    font-size: 0.9rem;
}

.admin-toggle-btn:hover {
    border-color: var(--accent);
}

.admin-panel {
    margin-top: 24px;
    background: #ffffff;
    border-radius: var(--radius);
    padding: 20px;
    border: 1px solid rgba(0, 0, 0, 0.08);
}

.admin-panel h2 {
    margin-top: 0;
    margin-bottom: 16px;
}

.admin-form label {
    display: block;
    margin-bottom: 8px;
    color: var(--muted);
    font-size: 0.9rem;
    font-weight: 500;
}

.form-group {
    margin-bottom: 24px;
}

/* Segmented Control */
.segmented-control {
    display: flex;
    background: #f1f5f9;
    backdrop-filter: blur(8px);
    border-radius: 12px;
    padding: 2px;
    border: 1px solid rgba(0, 0, 0, 0.05);
    gap: 2px;
    margin-top: 8px;
    box-shadow: inset 0 2px 4px rgba(0, 0, 0, 0.03);
}

.segment-btn {
    flex: 1;
    padding: 12px 20px;
    border: none;
    background: transparent;
    color: var(--muted);
    cursor: pointer;
    border-radius: 10px;
    font-family: var(--font);
    font-weight: 600;
    transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
    font-size: 0.85rem;
    position: relative;
    overflow: hidden;
    /* Fixes: Height consistency and centering. 
       Increased to 80px to safely accommodate 3-line text wrapping */
    min-height: 80px;
    display: flex;
    align-items: center;
    justify-content: center;
    text-align: center;
}

.segment-btn.active {
    background: var(--accent);
    color: white;
    /* Fix: Green shadow instead of violet */
    box-shadow: 0 4px 15px rgba(27, 155, 126, 0.4);
    text-shadow: 0 1px 2px rgba(0, 0, 0, 0.2);
}

.segment-btn:hover:not(.active) {
    background: rgba(255, 255, 255, 0.08);
    color: var(--text);
}

.segment-btn::after {
    content: '';
    position: absolute;
    right: -1px;
    top: 25%;
    height: 50%;
    width: 1px;
    background: rgba(0, 0, 0, 0.05);
}

.segment-btn:last-child::after,
.segment-btn.active::after,
.segment-btn.active+.segment-btn::after {
    display: none;
}

.admin-choice-item input[type="radio"],
.admin-choice-item input[type="checkbox"] {
    appearance: auto;
    -webkit-appearance: radio;
    width: auto;
    height: auto;
    border: none;
    /* Reset any custom borders */
    outline: none;
    background: transparent;
    cursor: pointer;
    margin: 0;
    accent-color: var(--accent);
    /* Native green dot/checkmark */
}

/* Ensure no custom outlines interfere */
.admin-choice-item input[type="radio"]:checked,
.admin-choice-item input[type="checkbox"]:checked {
    outline: none;
    box-shadow: none;
}

/* Remove any custom pseudo-elements from previous attempts */
.admin-choice-item input[type="radio"]::before,
.admin-choice-item input[type="radio"]:checked::before,
.admin-choice-item input[type="checkbox"]::before,
.admin-choice-item input[type="checkbox"]:checked::before {
    display: none;
    content: none;
}

/* Answer Image Upload Button - Compact Pill Style */
.admin-choice-add-image {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    min-width: 42px;
    height: 36px;
    padding: 0 10px;
    border-radius: 999px;
    border: 1px solid rgba(0, 0, 0, 0.08);
    /* Soft border */
    background-color: #ffffff !important;
    /* Ensure white pill background */
    box-shadow: 0 2px 4px rgba(15, 23, 42, 0.06) !important;
    cursor: pointer;
    font-size: 1.2rem;
    line-height: 1;
    margin-left: 4px;
    transition: all 0.2s ease;
}

.admin-choice-add-image:hover {
    transform: translateY(-1px);
    box-shadow: 0 4px 6px rgba(15, 23, 42, 0.1) !important;
    border-color: rgba(0, 0, 0, 0.15);
}

/* Make image buttons lighter */
.admin-form input[type="text"],
.admin-form input[type="number"],
.admin-form select,
.admin-form textarea {
    width: 100%;
    background: #ffffff;
    border: 1px solid #E3E8EF;
    border-radius: var(--radius);
    padding: 10px 16px;
    color: var(--text);
    font-family: var(--font);
    margin-top: 4px;
    transition: border-color 0.2s, box-shadow 0.2s;
}

.admin-form input:focus,
.admin-form select:focus,
.admin-form textarea:focus {
    border-color: #06C167;
    box-shadow: 0 0 0 2px rgba(6, 193, 103, 0.18);
    outline: none;
}

.admin-form textarea {
    min-height: 60px;
    resize: vertical;
}

.admin-question-item {
    background: var(--panel);
    border: 1px solid rgba(0, 0, 0, 0.05);
    border-radius: var(--radius);
    padding: 16px;
    margin-bottom: 12px;
}

.admin-question-item h3 {
    margin-top: 0;
    font-size: 1rem;
}

.admin-choice-item {
    display: flex;
    align-items: center;
    gap: 8px;
    margin-bottom: 8px;
}

.admin-choice-item input[type="text"] {
    flex: 1;
    margin: 0;
}

.admin-choice-item input[type="radio"] {
    margin: 0;
}

.admin-btn {
    /* Legacy styling, kept for safe fallback, but .btn is preferred */
    background: #ffffff;
    border: 1px solid rgba(0, 0, 0, 0.08);
    border-radius: var(--radius);
    padding: 10px 16px;
    color: var(--text);
    cursor: pointer;
    font-size: 0.9rem;
    margin-right: 8px;
}

.admin-btn:hover {
    border-color: var(--accent);
}

.admin-btn-primary {
    /* Legacy */
    background: var(--accent);
    border-color: var(--accent);
    color: white;
}

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

.admin-actions {
    margin-top: 16px;
    display: flex;
    gap: 8px;
}

.admin-share {
    margin-top: 16px;
    padding: 12px;
    background: #f8fafc;
    border-radius: var(--radius);
    border: 1px solid rgba(0, 0, 0, 0.05);
}

.admin-share code {
    display: block;
    word-break: break-all;
    color: var(--accent);
    font-size: 0.85rem;
}

.admin-question-actions {
    display: flex;
    gap: 8px;
    margin-bottom: 16px;
    flex-wrap: wrap;
}

/* --- New Modern Buttons --- */
.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: 8px;
    padding: 10px 20px;
    border-radius: var(--radius);
    border: 1px solid rgba(0, 0, 0, 0.08);
    font-family: var(--font);
    font-weight: 600;
    cursor: pointer;
    transition: all 0.2s cubic-bezier(0.25, 0.8, 0.25, 1);
    text-decoration: none;
    background: #ffffff;
    color: var(--text);
    box-shadow: 0 4px 6px -1px rgba(0, 0, 0, 0.05), 0 2px 4px -1px rgba(0, 0, 0, 0.03);
    font-size: 0.95rem;
}

.btn:hover {
    background: #f8fafc;
    border-color: rgba(0, 0, 0, 0.15);
}

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

.btn:focus {
    border-color: #06C167;
    box-shadow: 0 0 0 2px rgba(6, 193, 103, 0.18);
    outline: none;
}

/* Primary: Teal Green Gradient */
.btn-primary {
    background: linear-gradient(135deg, #1B9B7E, #22C997);
    color: white;
    border: 1px solid rgba(0, 0, 0, 0.05);
}

.btn-primary:hover {
    transform: translateY(-2px);
    box-shadow: 0 10px 15px -3px rgba(27, 155, 126, 0.3);
    background: linear-gradient(135deg, #168F6F, #1B9B7E);
    border-color: rgba(0, 0, 0, 0.1);
}

/* Danger: Red with Shake */
.btn-danger {
    background: var(--danger);
    color: white;
    border: 1px solid rgba(0, 0, 0, 0.05);
}

@keyframes shake {
    0% {
        transform: translateX(0);
    }

    25% {
        transform: translateX(-2px) rotate(-1deg);
    }

    50% {
        transform: translateX(2px) rotate(1deg);
    }

    75% {
        transform: translateX(-2px) rotate(-1deg);
    }

    100% {
        transform: translateX(0);
    }
}

.btn-danger:hover {
    transform: scale(1.05);
    animation: shake 0.4s ease-in-out;
    box-shadow: 0 10px 15px -3px rgba(248, 113, 113, 0.5);
    background: #ef4444;
}

/* Icon Button (Square-ish) */
.btn-icon {
    padding: 8px;
    min-width: 36px;
    height: 36px;
    border-radius: 8px;
    line-height: 0;
}

@media (max-width: 640px) {
    body {
        padding: 16px;
    }

    #app-root {
        padding: 18px 20px;
    }

    .quiz-header h1 {
        font-size: 1.2rem;
    }
}

/* Start Menu Styles */
.start-menu {
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    gap: 24px;
    text-align: center;
    min-height: 40vh;
    padding: 20px 20px;
}

/* Join Quiz Card */
.join-card {
    width: 100%;
    max-width: 460px;
    margin: 10px auto;
    padding: 1.8rem;
    background: #ffffff;
    border: 1px solid rgba(0, 0, 0, 0.08);
    border-radius: 24px;
    backdrop-filter: blur(20px);
    box-shadow: 0 20px 40px -12px rgba(0, 0, 0, 0.1);
    text-align: center;
    animation: slideUpFade 0.6s cubic-bezier(0.16, 1, 0.3, 1);
}

@keyframes slideUpFade {
    from {
        opacity: 0;
        transform: translateY(30px);
    }

    to {
        opacity: 1;
        transform: translateY(0);
    }
}

.join-card h1 {
    font-size: 1.8rem;
    margin-bottom: 1.2rem;
    background: linear-gradient(135deg, var(--accent), var(--accent-strong));
    -webkit-background-clip: text;
    background-clip: text;
    -webkit-text-fill-color: transparent;
    font-weight: 800;
}

.join-quiz-info {
    background: #f8fafc;
    border-radius: 16px;
    padding: 1.2rem;
    margin-bottom: 1.5rem;
    border: 1px solid rgba(0, 0, 0, 0.05);
    transition: transform 0.3s ease;
}

.join-quiz-info:hover {
    transform: scale(1.02);
}

.join-quiz-info h2 {
    font-size: 1.4rem;
    margin: 0 0 4px 0;
    color: var(--text);
    font-weight: 700;
}

.join-quiz-info p {
    margin: 0;
    color: var(--muted);
    font-size: 1rem;
    opacity: 0.9;
}

.join-input-group {
    text-align: left;
    margin-bottom: 1.8rem;
}

.join-label {
    display: block;
    margin-bottom: 10px;
    color: var(--muted);
    font-size: 0.95rem;
    font-weight: 600;
}

.join-input {
    width: 100%;
    background: #ffffff;
    border: 1px solid #E3E8EF;
    border-radius: var(--radius);
    padding: 1rem 1.2rem;
    color: var(--text);
    font-size: 1.1rem;
    transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
}

.join-input:focus {
    border-color: #06C167;
    background: #ffffff;
    box-shadow: 0 0 0 2px rgba(6, 193, 103, 0.18);
    outline: none;
}

.join-actions {
    display: flex;
    flex-direction: column;
    gap: 12px;
}

.btn-xl {
    padding: 1rem !important;
    font-size: 1.1rem !important;
    font-weight: 700 !important;
    border-radius: 14px !important;
}

.start-menu h1 {
    font-size: 2.5rem;
    margin-bottom: 16px;
    background: linear-gradient(135deg, var(--accent), #22C997);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.start-menu p {
    color: var(--muted);
    font-size: 1.1rem;
    margin-bottom: 40px;
}

.menu-actions {
    display: flex;
    gap: 20px;
    flex-wrap: wrap;
    justify-content: center;
}

.menu-actions .btn {
    min-width: 150px;
    padding: 16px 28px;
    font-size: 1.1rem;
}

@keyframes fadeIn {
    from {
        opacity: 0;
        transform: translateY(10px);
    }

    to {
        opacity: 1;
        transform: translateY(0);
    }
}

/* Student Input Form (Hidden by default) */
.student-form-container {
    max-width: 450px;
    width: 100%;
    margin: 0 auto;
    display: flex;
    flex-direction: column;
    gap: 16px;
    text-align: left;
    padding: 0 20px;
    /* Add padding to prevent edge touching */
}

.student-form-container label {
    display: block;
    margin-bottom: 8px;
    color: var(--muted);
}

/* Dashboard Styles */
.dashboard-view {
    width: 100%;
    margin-top: 20px;
    animation: fadeIn 0.5s ease-out;
}

.dashboard-view h2 {
    text-align: center;
    margin-bottom: 24px;
    background: linear-gradient(135deg, var(--accent), #22C997);
    -webkit-background-clip: text;
    background-clip: text;
    -webkit-text-fill-color: transparent;
}

.dashboard-table {
    width: 100%;
    border-collapse: collapse;
    background: #ffffff;
    border: 1px solid rgba(0, 0, 0, 0.05);
    border-radius: var(--radius);
    overflow: hidden;
    margin-bottom: 24px;
}

.dashboard-table th,
.dashboard-table td {
    padding: 16px;
    text-align: left;
    border-bottom: 1px solid rgba(0, 0, 0, 0.05);
}

.dashboard-table th {
    background: #f8fafc;
    color: var(--muted);
    font-weight: 600;
}

.dashboard-table tr:hover {
    background: #f1f5f9;
}

.score-good {
    color: var(--success);
    font-weight: bold;
}

.score-avg {
    color: var(--accent);
}

.score-bad {
    color: var(--danger);
}

.no-results {
    text-align: center;
    color: var(--muted);
    padding: 40px;
    background: #ffffff;
    border: 1px solid rgba(0, 0, 0, 0.05);
    border-radius: var(--radius);
}

.text-danger {
    color: var(--danger) !important;
}

.text-success {
    color: var(--success) !important;
}

.detail-modal {
    position: fixed;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
    width: min(800px, 95vw);
    max-height: 90vh;
    z-index: 2000;
    box-shadow: 0 40px 80px rgba(0, 0, 0, 0.2);
    overflow-y: auto;
    background: #ffffff;
    padding: 30px;
    border: 1px solid rgba(0, 0, 0, 0.1);
    border-radius: var(--radius);
}

/* --- Advanced Question Types & Exam Mode --- */
.exam-navigation {
    display: flex;
    flex-wrap: wrap;
    gap: 10px;
    margin-bottom: 24px;
    justify-content: center;
    padding: 15px;
    background: #f8fafc;
    border-radius: var(--radius);
    border: 1px solid rgba(0, 0, 0, 0.05);
}

.nav-dot {
    width: 38px;
    height: 38px;
    border-radius: 50%;
    border: 1px solid rgba(0, 0, 0, 0.1);
    background: transparent;
    color: var(--text);
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    font-weight: 600;
    font-size: 0.85rem;
    transition: all 0.2s cubic-bezier(0.4, 0, 0.2, 1);
}

.nav-dot:hover {
    border-color: var(--accent);
    transform: translateY(-2px);
}

.nav-dot.active {
    border-color: var(--accent);
    background: rgba(27, 155, 126, 0.08);
    box-shadow: 0 0 10px rgba(27, 155, 126, 0.2);
}

.nav-dot.answered {
    background: var(--accent);
    border-color: var(--accent);
    color: white;
}

.quiz-input {
    width: 100%;
    background: #ffffff;
    border: 1px solid #E3E8EF;
    color: var(--text);
    padding: 14px;
    border-radius: var(--radius);
    font-family: inherit;
    font-size: 1.1rem;
    transition: border-color 0.2s, box-shadow 0.2s;
}

.quiz-input:focus {
    outline: none;
    border-color: #06C167;
    box-shadow: 0 0 0 2px rgba(6, 193, 103, 0.18);
}

.blanks-container {
    display: flex;
    flex-direction: column;
    gap: 12px;
    text-align: left;
    max-width: 500px;
    margin: 0 auto;
}

.blank-row {
    display: flex;
    align-items: center;
    gap: 12px;
}

.blank-label {
    min-width: 25px;
    font-weight: bold;
    color: var(--accent);
}

.mc-btn {
    text-align: left;
    display: flex;
    align-items: center;
    gap: 15px;
    padding: 16px !important;
}

.mc-indicator {
    width: 32px;
    height: 32px;
    border-radius: 50%;
    background: rgba(255, 255, 255, 0.08);
    display: flex;
    align-items: center;
    justify-content: center;
    font-weight: 700;
    font-size: 0.8rem;
    flex-shrink: 0;
    transition: all 0.2s;
    border: 1px solid rgba(0, 0, 0, 0.05);
}

.answer-btn.selected {
    background: rgba(27, 155, 126, 0.08);
    border-color: var(--accent);
    box-shadow: 0 0 15px rgba(27, 155, 126, 0.15);
}

.answer-btn.selected .mc-indicator {
    background: var(--accent);
    color: white;
    transform: scale(1.1);
}

.answer-btn.checkbox-style .mc-indicator {
    border-radius: 6px;
}

.answer-btn.checkbox-style.selected .mc-indicator::after {
    content: '✓';
    font-size: 1.1rem;
}

/* Result Item Feedback */
.result-item.pending {
    border-left-color: var(--accent) !important;
}

.pending-bg {
    background: rgba(27, 155, 126, 0.03) !important;
}

.incorrect-bg {
    background: rgba(248, 113, 113, 0.05) !important;
}

.badge-pending {
    border-color: var(--accent);
    color: var(--accent);
}

.uploaded-preview {
    border: 1px solid rgba(0, 0, 0, 0.08);
    box-shadow: 0 10px 20px rgba(0, 0, 0, 0.1);
}

.incorrect-bg {
    background: rgba(248, 113, 113, 0.05);
}

/* Topics Page Styles */
.bundle-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(300px, 1fr));
    gap: 20px;
}

.bundle-card {
    background: rgba(0, 0, 0, 0.03) !important;
    border: 1px solid rgba(0, 0, 0, 0.08) !important;
    border-radius: 16px !important;
    padding: 24px;
    display: flex;
    flex-direction: column;
    transition: transform 0.2s, background 0.2s, box-shadow 0.2s;
}

.bundle-card:hover {
    transform: translateY(-4px);
    background: rgba(0, 0, 0, 0.05) !important;
    box-shadow: 0 10px 20px rgba(0, 0, 0, 0.05);
}

/* Page Logo */
#app-logo {
    position: fixed;
    top: 15px;
    left: 20px;
    height: 40px;
    cursor: pointer;
    transition: opacity 0.2s, transform 0.2s;
    z-index: 1001;
}

#app-logo:hover {
    opacity: 0.8;
    transform: scale(1.05);
}

@media (max-width: 768px) {
    #app-logo {
        position: absolute;
        height: 32px;
        top: 10px;
        left: 15px;
    }

    #topics-back-btn {
        display: none !important;
    }

    .bundle-grid {
        grid-template-columns: 1fr !important;
    }

    .bundle-card {
        padding: 20px;
    }

    .topics-page-container h1 {
        font-size: 2rem !important;
    }

    .topics-page-container h2 {
        font-size: 1.5rem !important;
    }
}