*{
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

:root {
    --primary-color: #3B82F6;
    --success-color: #10B981;
    --danger-color: #EF4444;
    --warning-color: #F59E0B;
    --info-color: #8B5CF6;
    --bg-color: #F3F4F6;
    --card-bg: #FFFFFF;
    --text-primary: #1F2937;
    --text-secondary: #6B7280;
    --border-color: #E5E7EB;
    --shadow: 0 10px 30px rgba(0,0,0,0.1);
    --shadow-lg: 0 20px 40px rgba(0,0,0,0.15);
    --spacing-xs: 0.5rem;
    --spacing-sm: 1rem;
    --spacing-md: 1.5rem;
    --spacing-lg: 2rem;
    --spacing-xl: 3rem;
    --radius-sm: 0.375rem;
    --radius-md: 0.5rem;
    --radius-lg: 0.75rem;
    --radius-xl: 1rem;
    --transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
}

body {
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    min-height: 100vh;
    padding: var(--spacing-md);
    color: var(--text-primary);
}

/* ============================================
   CONTAINER
   ============================================ */
.container{
    max-width: 900px;
    margin: 0 auto;
    animation: fadeIn 0.6s ease;
}
@keyframes fadeIn {
    from {
        opacity: 0;
        transform: translateY(20px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

/* ============================================
   HEADER
   ============================================ */
header{
    text-align: center;
    margin-bottom: var(--spacing-lg);
    color: #FFFFFF;
}

header h1{
    font-size: 2.5rem;
    margin-bottom: var(--spacing-xs);
    text-shadow: 2px 2px 4px rgba(0,0,0,0.2);
}

.subtitle{
    font-size: 1.1rem;
    opacity: 0.9;
}

/* ============================================
   QUIZ CONTAINER
   ============================================ */
.quiz-container{
    background: var(--card-bg);
    border-radius: var(--radius-xl);
    padding: var(--spacing-xl);
    box-shadow: var(--shadow-lg);
    min-height: 500px;
}
/* ============================================
   START SCREEN
   ============================================ */
.welcome-section{
    font-size: 4rem;
    color: var(--primary-color);
    margin-bottom: var(--spacing-md);
    animation: bounce 2s ease-in-out infinite;
}

@keyframes bounce {
    0%, 100% {
        transform: translateY(0);
    }
    50% {
        transform: translateY(-20px);
    }
}

.welcome-section h2{
    font-size: 2rem;
    margin-bottom: var(--spacing-sm);
    color: var(--text-primary);
}

.welcome-section p{
    color: var(--text-secondary);
    font-size: 1.1rem;
}

/* ============================================
   QUIZ SETTINGS
   ============================================ */
.quiz-settings{
    background: var(--bg-color);
    padding: var(--spacing-lg);
    border-radius: var(--radius-lg);
    margin-bottom: var(--spacing-lg);
}

.settings-group{
    margin-bottom: var(--spacing-md);
}
.settings-group:last-child{
    margin-bottom: 0;
}

.settings-group label{
    display: block;
    margin-bottom: var(--spacing-sm);
    font-weight: 600;
    color: var(--text-primary);
}

.settings-group label i{
    color: var(--primary-color);
    margin-right: var(--spacing-xs);
}

.select-input{
    width: 100%;
    padding: var(--spacing-sm) var(--spacing-md);
    border: 2px solid var(--border-color);
    border-radius: var(--radius-md);
    font-size: 1rem;
    background: #FFFFFF;
    cursor: pointer;
    transition: var(--transition);
}

.select-input:focus{
    outline: none;
    border-color: var(--primary-color);
    box-shadow: 0 0 0 3px rgba(59,130,246,0.1);
}

.toggle-group{
    display: flex;
    gap: var(--spacing-sm);
    flex-wrap: wrap;
}

.toggle-option{
    flex: 1;
    min-width: 120px;
    padding: var(--spacing-sm);
    background: #FFFFFF;
    border: 2px solid var(--border-color);
    border-radius: var(--radius-md);
    cursor: pointer;
    transition: var(--transition);
    display: flex;
    align-items: center;
    gap: var(--spacing-xs);
}

.toggle-option:hover{
    border-color: var(--primary-color);
    background: rgba(59, 130, 246, 0.05);
}

.toggle-option input[type="radio"] {
    cursor: pointer;
}

.toggle-option input[type="radio"]:checked + span {
    color: var(--primary-color);
    font-weight: 600;
}
/* ============================================
   BUTTONS
   ============================================ */
.btn{
    padding: var(--spacing-sm) var(--spacing-lg);
    border: none;
    border-radius: var(--radius-md);
    font-size: 1rem;
    font-weight: 600;
    cursor: pointer;
    transition: var(--transition);
    display: inline-flex;
    align-items: center;
    gap: var(--spacing-xs);
    justify-content: center;
}

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

.btn-primary:hover{
    background: #2563EB;
    transform: translateY(-2px);
    box-shadow: var(--shadow);
}

.btn-success{
    background: var(--success-color);
    color: #FFFFFF;
}

.btn-success:hover{
    background: #059669;
    transform: translateY(-2px);
}

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

.btn-secondary:hover{
    background: #4B5563;
}

.btn-warning{
    background: var(--warning-color);
    color: #FFFFFF;
}

.btn-warning:hover{
    background: #D97706;
}

.btn-info{
    background: var(--info-color);
    color: #FFFFFF;
}

.btn-info:hover{
    background: #7C3AED;
}

.btn-outline{
    background: transparent;
    border: 2px solid var(--border-color);
    color: var(--text-primary);
}

.btn-outline:hover{
    border-color: var(--primary-color);
    color: var(--primary-color);
}

.btn-large{
    width: 100%;
    padding: var(--spacing-md) var(--spacing-lg);
    font-size: 1.2rem;
}

.btn:disabled {
    opacity: 0.5;
    cursor: not-allowed;
}

.btn:disabled:hover {
    transform: none;
    box-shadow: none;
}
/* ============================================
   HIGH SCORES PREVIEW
   ============================================ */
   .high-scores-preview{
    margin-top: var(--spacing-lg);
    padding: var(--spacing-lg);
    background: var(--bg-color);
    border-radius: var(--radius-lg);
   }

   .high-scores-preview h3{
    margin-bottom: var(--spacing-md);
    color: var(--text-primary);
   }

   #top-scores-list{
    display: flex;
    flex-direction: column;
    gap: var(--spacing-sm);
   }

   .score-item{
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: var(--spacing-sm);
    background: #FFFFFF;
    border-radius: var(--radius-md);
   }

   .empty-state{
    text-align: center;
    color: var(--text-secondary);
    font-style: italic;
    padding: var(--spacing-md);
   }

   /* ============================================
   QUIZ SCREEN
   ============================================ */
   .quiz-header{
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: var(--spacing-lg);
    flex-wrap: wrap;
    gap: var(--spacing-md);
   }

   .quiz-info{
    display: flex;
    gap: var(--spacing-lg);
    flex-wrap: wrap;
   }

   .info-item{
    display: flex;
    align-items: center;
    gap: var(--spacing-xs);
    color: var(--text-secondary);
   }

   .info-item i{
    color: var(--primary-color);
   }

   .info-item strong{
    color: var(--text-primary);
   }

   .timer-section{
    display: flex;
    align-items: center;
    gap: var(--spacing-sm);
    padding: var(--spacing-sm) var(--spacing-md);
    background: var(--bg-color);
    border-radius: var(--radius-md);
   }

   .timer-icon i{
    color: var(--warning-color);
    font-size: 1.5rem;
    animation: pulse 1s ease-in-out infinite;
   }

   @keyframes pulse {
    0%, 100% {
        opacity: 1;
    }
    50% {
        opacity: 0.5;
    }
}

.timer-display {
    font-size: 1.5rem;
    font-weight: 700;
    color: var(--text-primary);
}

.timer-display.warning{
    color: var(--danger-color);
}
/* ============================================
   PROGRESS BAR
   ============================================ */
   .progress-container{
    height: 8px;
    background: var(--bg-color);
    border-radius: 999px;
    overflow: hidden;
    margin-bottom: var(--spacing-lg);
   }

   .progress-bar{
    height: 100%;
    background: linear-gradient(90deg, var(--primary-color), var(--success-color));
    border-radius: 999px;
    transition: width 0.3s ease;
   }

   /* ============================================
   QUESTION CARD
   ============================================ */
   .question-card{
    margin-bottom: var(--spacing-lg);
   }

   .question-header{
    display: flex;
    gap: var(--spacing-sm);
    margin-bottom: var(--spacing-md);
    flex-wrap: wrap;
   }

   .category-badge{
    padding: var(--spacing-xs) var(--spacing-sm);
    background: rgba(59, 130, 246, 0.1);
    color: var(--primary-color);
    border-radius: var(--radius-sm);
    font-size: 0.85rem;
    font-weight: 600;
   }

   .difficulty-badge{
    padding: var(--spacing-xs) var(--spacing-sm);
    background: rgba(245, 158, 11, 0.1);
    color: var(--warning-color);
    border-radius: var(--radius-sm);
    font-size: 0.85rem;
    font-weight: 600;
   }

   .question-text{
    font-size: 1.5rem;
    color: var(--text-primary);
    margin-bottom: var(--spacing-lg);
    line-height: 1.6;
   }

   /* ============================================
   OPTIONS
   ============================================ */
.options-container{
    display: flex;
    flex-direction: column;
    gap: var(--spacing-md);
}

.option-item{
    display: flex;
    align-items: center;
    gap: var(--spacing-md);
    padding: var(--spacing-md);
    background: var(--bg-color);
    border: 2px solid var(--border-color);
    border-radius: var(--radius-lg);
    cursor: pointer;
    transition: var(--transition);
    position: relative;
}

.option-item:hover{
    border-color: var(--primary-color);
    background: rgba(59, 130, 246, 0.05);
    transform: translateX(5px);
}

.option-label{
    width: 40px;
    height: 40px;
    display: flex;
    align-items: center;
    justify-content: center;
    background: #FFFFFF;
    border-radius: 50%;
    font-weight: 700;
    font-size: 1.1rem;
    color: var(--text-primary);
    flex-shrink: 0;
}

.option-text{
    flex: 1;
    font-size: 1.1rem;
    color: var(--text-primary);
}

.option-icon{
    font-size: 1.5rem;
    opacity: 0;
    transition: var(--transition);
}
.option-item.selected{
    border-color: var(--primary-color);
    background: rgba(59, 130, 246, 0.1);
}

.option-item.selected .option-label{
    background: var(--primary-color);
    color: #FFFFFF;
}

.option-item.selected .option-icon{
    opacity: 1;
    color: var(--primary-color);
}

.option-item.correct{
    border-color: var(--success-color);
    background: rgba(16, 185, 129, 0.1);
    pointer-events: none;
}

.option-item.correct .option-label{
    background: var(--success-color);
    color: #FFFFFF;
}

.option-item.correct .option-icon{
    opacity: 1;
    color: var(--success-color);
}

.option-item.correct .option-icon::before {
    content: "\f00c"; /* Font Awesome check icon */
    font-family: "Font Awesome 6 Free";
    font-weight: 900;
}

.option-item.wrong{
    border-color: var(--danger-color);
    background: rgba(239, 68, 68, 0.1);
    pointer-events: none;
}

.option-item.wrong .option-label{
    background: var(--danger-color);
    color: #FFFFFF;
}

.option-item.wrong .option-icon{
    opacity: 1;
    color: var(--danger-color);
}

.option-item.wrong .option-icon::before {
    content: "\f00d"; /* Font Awesome times icon */
    font-family: "Font Awesome 6 Free";
    font-weight: 900;
}

.option-item.disabled {
    pointer-events: none;
    opacity: 0.6;
}

/* ============================================
   HINT SECTION
   ============================================ */
.hint-section{
    margin-top: var(--spacing-lg);
    padding: var(--spacing-md);
    background: rgba(139, 92, 246, 0.1);
    border-left: 4px solid var(--info-color);
    border-radius: var(--radius-md);
    display: flex;
    align-items: center;
    gap: var(--spacing-sm);
    animation: slideDown 0.3s ease;
}

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

.hint-section i{
    color: var(--info-color);
    font-size: 1.5rem;
}

.hint-section p{
    color: var(--text-primary);
    margin: 0;
}

/* ============================================
   QUIZ NAVIGATION
   ============================================ */
   .quiz-navigation{
    display: flex;
    justify-content: space-between;
    align-items: center;
    flex-wrap: wrap;
    gap: var(--spacing-sm);
   }

   .nav-buttons{
    display: flex;
    gap: var(--spacing-sm);
   }

   /* ============================================
   RESULTS SCREEN
   ============================================ */
.results-screen{
    text-align: center;
}

.results-animation{
    font-size: 5rem;
    margin-bottom: var(--spacing-md);
    animation: bounceIn 0.8s ease;
}

@keyframes bounceIn {
    0% {
        transform: scale(0);
    }
    50% {
        transform: scale(1.2);
    }
    100% {
        transform: scale(1);
    }
}

.results-animation.excellent{
    color: var(--success-color);
}

.results-animation.good{
    color: var(--primary-color);
}

.results-animation.average{
    color: var(--warning-color);
}

.results-animation.poor{
    color: var(--danger-color);
}

#results-title{
    font-size: 2rem;
    margin-bottom: var(--spacing-xs);
    color: var(--text-primary);
}

#results-subtitle{
    color: var(--text-secondary);
    font-size: 1.1rem;
    margin-bottom: var(--spacing-lg);
}
/* ============================================
   SCORE CARD
   ============================================ */

   .score-card{
    background: var(--bg-color);
    padding: var(--spacing-xl);
    border-radius: var(--radius-xl);
    margin-bottom: var(--spacing-lg);
   }

   .score-main h3{
    margin-bottom: var(--spacing-sm);
    color: var(--text-secondary);
   }

   .score-value{
    font-size: 4rem;
    font-weight: 700;
    color: var(--primary-color);
    margin-bottom: var(--spacing-sm);
   }

   .score-total{
    font-size: 2rem;
    color: var(--text-secondary);
   }

   .score-percentage{
    font-size: 1.5rem;
    color: var(--text-secondary);
   }

   .score-breakdown{
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: var(--spacing-md);
    margin-top: var(--spacing-lg);
    padding-top: var(--spacing-lg);
    border-top: 2px solid var(--border-color);
   }

   .breakdown-item{
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: var(--spacing-xs);
   }

   .breakdown-item i{
    font-size: 2rem;
   }

   .breakdown-item.correct i{
    color: var(--success-color);
   }

   .breakdown-item.wrong i{
    color: var(--danger-color);
   }

   .breakdown-item.skipped i{
    color: var(--text-secondary);
   }

   .breakdown-item strong{
    font-size: 1.5rem;
    color: var(--text-primary);
   }

   .breakdown-item span{
    font-size: 0.9rem;
    color: var(--text-secondary);
   }

   .time-taken{
    display: flex;
    align-items: center;
    justify-content: center;
    gap: var(--spacing-sm);
    margin-top: var(--spacing-lg);
    padding-top: var(--spacing-lg);
    border-top: 2px solid var(--border-color);
    color: var(--text-secondary);
   }

   .time-taken i{
    color: var(--primary-color);
   }
   /* ============================================
   PERFORMANCE MESSAGE
   ============================================ */
.performance-message{
    padding: var(--spacing-md);
    background: rgba(59, 130, 246, 0.1);
    border-radius: var(--radius-lg);
    margin-bottom: var(--spacing-lg);
    display: flex;
    align-items: center;
    justify-content: center;
    gap: var(--spacing-sm);
}

.performance-message i{
    color: var(--primary-color);
    font-size: 1.5rem;
}

.performance-message p{
    margin: 0;
    color: var(--text-primary);
    font-weight: 600;
}

/* ============================================
   RESULTS ACTIONS
   ============================================ */
.results-actions {
    display: flex;
    gap: var(--spacing-sm);
    justify-content: center;
    flex-wrap: wrap;
}

/* ============================================
   HIGH SCORE BANNER
   ============================================ */

   .high-score-banner{
    position: fixed;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
    background: linear-gradient(135deg, #FFD700, #FFA500);
    padding: var(--spacing-xl);
    border-radius: var(--radius-xl);
    box-shadow: 0 20px 60px rgba(0, 0, 0, 0.3);
    z-index: 1000;
    animation: highScorePop 1s ease;
    display: flex;
    align-items: center;
    gap: var(--spacing-md);
    color: #FFFFFF;
    font-size: 1.5rem;
    font-weight: 700;
   }

   @keyframes highScorePop {
    0% {
        transform: translate(-50%, -50%) scale(0) rotate(0deg);
    }
    50% {
        transform: translate(-50%, -50%) scale(1.2) rotate(10deg);
    }
    100% {
        transform: translate(-50%, -50%) scale(1) rotate(0deg);
    }
}

.high-score-banner i {
    font-size: 3rem;
}

/* ============================================
   REVIEW SCREEN
   ============================================ */
.review-header{
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: var(--spacing-lg);
    flex-wrap: wrap;
    gap: var(--spacing-md);
}

.review-header h2{
    color: var(--text-primary);
}

.review-container {
    display: flex;
    flex-direction: column;
    gap: var(--spacing-lg);
    max-height: 600px;
    overflow-y: auto;
    padding-right: var(--spacing-sm);
}

.review-item {
    background: var(--bg-color);
    padding: var(--spacing-lg);
    border-radius: var(--radius-lg);
    border-left: 4px solid transparent;
}

.review-item.correct {
    border-left-color: var(--success-color);
}

.review-item.wrong {
    border-left-color: var(--danger-color);
}

.review-item.skipped {
    border-left-color: var(--text-secondary);
}

.review-question {
    font-weight: 600;
    margin-bottom: var(--spacing-sm);
    color: var(--text-primary);
}

.review-answers {
    display: flex;
    flex-direction: column;
    gap: var(--spacing-xs);
    font-size: 0.95rem;
}

.review-answers div {
    padding: var(--spacing-xs);
}

.review-answers .correct-answer {
    color: var(--success-color);
    font-weight: 600;
}

.review-answers .your-answer {
    color: var(--text-secondary);
}

.review-answers .your-answer.wrong {
    color: var(--danger-color);
}

/* ============================================
   TOAST
   ============================================ */
.toast {
    position: fixed;
    bottom: 2rem;
    right: 2rem;
    background: var(--text-primary);
    color: white;
    padding: var(--spacing-md) var(--spacing-lg);
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow-lg);
    display: flex;
    align-items: center;
    gap: var(--spacing-sm);
    transform: translateY(150%);
    transition: transform 0.3s ease;
    z-index: 2000;
}

.toast.show {
    transform: translateY(0);
}

.toast i {
    font-size: 1.25rem;
}
/* ============================================
   FOOTER
   ============================================ */
footer {
    text-align: center;
    color: white;
    font-size: 0.9rem;
    margin-top: var(--spacing-xl);
}

footer a {
    color: white;
    text-decoration: none;
    border-bottom: 1px solid white;
}

.shortcuts {
    margin-top: var(--spacing-sm);
    font-size: 0.85rem;
    opacity: 0.9;
}

kbd {
    background: rgba(255, 255, 255, 0.2);
    padding: 0.2rem 0.5rem;
    border-radius: var(--radius-sm);
    font-family: monospace;
}

/* ============================================
   RESPONSIVE DESIGN
   ============================================ */
@media (max-width: 768px) {
    header h1 {
        font-size: 2rem;
    }

    .quiz-container {
        padding: var(--spacing-md);
    }

    .quiz-header {
        flex-direction: column;
        align-items: flex-start;
    }

    .question-text {
        font-size: 1.25rem;
    }

    .option-text {
        font-size: 1rem;
    }

    .quiz-navigation {
        flex-direction: column;
    }

    .nav-buttons {
        width: 100%;
        flex-direction: column;
    }

    .nav-buttons .btn {
        width: 100%;
    }

    .score-breakdown {
        grid-template-columns: 1fr;
    }

    .results-actions {
        flex-direction: column;
    }

    .results-actions .btn {
        width: 100%;
    }

    .toast {
        bottom: 1rem;
        right: 1rem;
        left: 1rem;
    }
}

@media (max-width: 480px) {
    .welcome-icon {
        font-size: 3rem;
    }

    .welcome-section h2 {
        font-size: 1.5rem;
    }

    .score-value {
        font-size: 3rem;
    }

    .results-animation {
        font-size: 4rem;
    }

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

    .toggle-option {
        width: 100%;
    }
}