/* Mobile-First Reset - Zero Padding for Maximum Screen Space */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
    -webkit-tap-highlight-color: transparent;
}

:root {
    --primary-color: #00796B;
    --primary-dark: #004D40;
    --success-color: #4CAF50;
    --error-color: #F44336;
    --warning-color: #FFC107;
    --text-dark: #212121;
    --text-light: #FFFFFF;
    --bg-light: #F5F5F5;
    --shadow: 0 2px 8px rgba(0, 0, 0, 0.1);
    --shadow-lg: 0 4px 16px rgba(0, 0, 0, 0.2);
}

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen, Ubuntu, Cantarell, sans-serif;
    background: linear-gradient(135deg, var(--primary-color) 0%, var(--primary-dark) 100%);
    color: var(--text-dark);
    height: 100vh;
    overflow: hidden;
    position: fixed;
    width: 100%;
    touch-action: manipulation;
}

/* Progress Bar - Fixed at Top */
#progress-container {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    height: 4px;
    background: rgba(255, 255, 255, 0.2);
    z-index: 1000;
}

#progress-bar {
    height: 100%;
    background: linear-gradient(90deg, var(--success-color), var(--warning-color));
    width: 0%;
    transition: width 0.3s ease;
    box-shadow: 0 0 10px rgba(76, 175, 80, 0.5);
}

#progress-text {
    position: fixed;
    top: 8px;
    right: 12px;
    color: var(--text-light);
    font-size: 0.75rem;
    font-weight: 600;
    z-index: 1001;
    background: rgba(0, 0, 0, 0.3);
    padding: 4px 8px;
    border-radius: 12px;
    backdrop-filter: blur(10px);
}

/* Score Display - Top Left */
#score-container {
    position: fixed;
    top: 8px;
    left: 8px;
    display: flex;
    gap: 6px;
    z-index: 1001;
}

.score-item {
    background: rgba(0, 0, 0, 0.3);
    backdrop-filter: blur(10px);
    padding: 6px 10px;
    border-radius: 12px;
    display: flex;
    align-items: center;
    gap: 4px;
    font-weight: 600;
    font-size: 0.85rem;
    color: var(--text-light);
    min-width: 50px;
    justify-content: center;
}

.score-item.correct {
    background: rgba(76, 175, 80, 0.3);
}

.score-item.incorrect {
    background: rgba(244, 67, 54, 0.3);
}

.score-item.percentage {
    background: rgba(255, 193, 7, 0.3);
    min-width: 60px;
}

.score-label {
    font-size: 1rem;
}

/* Quiz Container - Full Screen */
#quiz-container {
    height: 100vh;
    display: flex;
    align-items: center;
    justify-content: center;
    padding: 60px 0 80px 0;
}

/* Card Container - 3D Perspective */
#card-container {
    width: 100%;
    height: 100%;
    perspective: 1000px;
    padding: 12px;
}

/* Card - 3D Flip Effect */
.card {
    position: relative;
    width: 100%;
    height: 100%;
    transform-style: preserve-3d;
    transition: transform 0.6s cubic-bezier(0.4, 0, 0.2, 1);
}

.card.flipped {
    transform: rotateY(180deg);
}

.card-face {
    position: absolute;
    width: 100%;
    height: 100%;
    backface-visibility: hidden;
    border-radius: 20px;
    padding: 24px;
    display: flex;
    flex-direction: column;
    box-shadow: var(--shadow-lg);
    overflow-y: auto;
    -webkit-overflow-scrolling: touch;
}

.card-front {
    background: var(--text-light);
}

.card-back {
    background: var(--text-light);
    transform: rotateY(180deg);
    justify-content: center;
    align-items: center;
    text-align: center;
}

/* Card Back - Correct/Incorrect States */
.card.correct .card-back {
    background: linear-gradient(135deg, #4CAF50 0%, #45a049 100%);
    color: var(--text-light);
}

.card.incorrect .card-back {
    background: linear-gradient(135deg, #F44336 0%, #da190b 100%);
    color: var(--text-light);
}

/* Category Badge */
.category {
    display: inline-block;
    background: var(--primary-color);
    color: var(--text-light);
    padding: 6px 12px;
    border-radius: 20px;
    font-size: 0.75rem;
    font-weight: 600;
    margin-bottom: 12px;
    align-self: flex-start;
}

/* Question Number */
.question-number {
    font-size: 0.9rem;
    color: var(--primary-color);
    font-weight: 700;
    margin-bottom: 8px;
}

/* Question Text */
.question-text {
    font-size: 1.25rem;
    font-weight: 600;
    color: var(--text-dark);
    margin-bottom: 20px;
    line-height: 1.5;
    flex-shrink: 0;
}

/* Answers Container */
.answers-container {
    display: flex;
    flex-direction: column;
    gap: 12px;
    flex: 1;
    overflow-y: auto;
}

/* Answer Button */
.answer-option {
    background: var(--warning-color);
    color: var(--text-dark);
    padding: 16px;
    border-radius: 12px;
    border: none;
    font-size: 1rem;
    font-weight: 500;
    cursor: pointer;
    transition: all 0.2s ease;
    text-align: left;
    line-height: 1.4;
    box-shadow: var(--shadow);
    min-height: 56px;
    display: flex;
    align-items: center;
}

.answer-option:active {
    transform: scale(0.98);
}

.answer-option.selected {
    background: var(--primary-color);
    color: var(--text-light);
    box-shadow: 0 4px 12px rgba(0, 121, 107, 0.4);
    transform: scale(1.02);
}

.answer-option.correct {
    background: var(--success-color);
    color: var(--text-light);
    animation: pulse-correct 0.5s ease;
}

.answer-option.incorrect {
    background: var(--error-color);
    color: var(--text-light);
    animation: shake 0.4s ease;
}

/* Result Message */
.result-message {
    font-size: 2.5rem;
    font-weight: 700;
    margin-bottom: 24px;
    animation: fade-in 0.4s ease;
}

.correct-answer-display {
    font-size: 1.1rem;
    line-height: 1.6;
    max-width: 90%;
    animation: slide-up 0.4s ease 0.2s both;
}

.correct-answer-display strong {
    display: block;
    font-size: 0.9rem;
    margin-bottom: 12px;
    opacity: 0.9;
}

/* Action Buttons */
#action-buttons {
    position: fixed;
    bottom: 0;
    left: 0;
    right: 0;
    display: flex;
    gap: 0;
    background: rgba(0, 0, 0, 0.05);
    backdrop-filter: blur(10px);
    border-top: 1px solid rgba(255, 255, 255, 0.1);
}

.btn {
    flex: 1;
    padding: 16px;
    border: none;
    font-size: 0.95rem;
    font-weight: 600;
    cursor: pointer;
    transition: all 0.2s ease;
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 6px;
    color: var(--text-light);
}

.btn:active {
    transform: scale(0.97);
}

.btn-primary {
    background: rgba(76, 175, 80, 0.9);
}

.btn-secondary {
    background: rgba(244, 67, 54, 0.9);
}

.btn span {
    font-size: 1.2rem;
}

/* Modal */
.modal {
    display: none;
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: rgba(0, 0, 0, 0.8);
    z-index: 2000;
    align-items: center;
    justify-content: center;
    padding: 20px;
    animation: fade-in 0.3s ease;
}

.modal.show {
    display: flex;
}

.modal-content {
    background: var(--text-light);
    border-radius: 20px;
    width: 100%;
    max-width: 500px;
    max-height: 90vh;
    display: flex;
    flex-direction: column;
    box-shadow: var(--shadow-lg);
    animation: slide-up 0.3s ease;
}

.modal-header {
    padding: 20px;
    border-bottom: 1px solid #e0e0e0;
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.modal-header h2 {
    font-size: 1.5rem;
    color: var(--primary-color);
}

.close-btn {
    background: none;
    border: none;
    font-size: 2rem;
    color: #999;
    cursor: pointer;
    padding: 0;
    width: 36px;
    height: 36px;
    display: flex;
    align-items: center;
    justify-content: center;
    border-radius: 50%;
    transition: all 0.2s ease;
}

.close-btn:hover {
    background: #f0f0f0;
    color: var(--text-dark);
}

.modal-body {
    padding: 20px;
    overflow-y: auto;
}

.results-summary {
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: 12px;
    margin-bottom: 24px;
}

.summary-item {
    background: var(--bg-light);
    padding: 16px;
    border-radius: 12px;
    text-align: center;
}

.summary-item.highlight {
    grid-column: 1 / -1;
    background: var(--primary-color);
    color: var(--text-light);
}

.summary-label {
    font-size: 0.85rem;
    margin-bottom: 8px;
    opacity: 0.8;
}

.summary-value {
    font-size: 1.8rem;
    font-weight: 700;
}

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

.incorrect-text {
    color: var(--error-color);
}

.wrong-answers-list {
    margin-top: 20px;
}

.wrong-answers-list h3 {
    font-size: 1.1rem;
    margin-bottom: 12px;
    color: var(--primary-color);
}

.wrong-answer-item {
    background: #fff3e0;
    padding: 12px;
    border-radius: 8px;
    margin-bottom: 8px;
    border-left: 4px solid var(--warning-color);
}

.wrong-answer-item .question-id {
    font-weight: 700;
    color: var(--primary-color);
    margin-bottom: 4px;
}

.wrong-answer-item .correct-ans {
    font-size: 0.9rem;
    color: var(--text-dark);
}

/* Animations */
@keyframes pulse-correct {
    0%, 100% { transform: scale(1); }
    50% { transform: scale(1.05); }
}

@keyframes shake {
    0%, 100% { transform: translateX(0); }
    25% { transform: translateX(-10px); }
    75% { transform: translateX(10px); }
}

@keyframes fade-in {
    from {
        opacity: 0;
    }
    to {
        opacity: 1;
    }
}

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

/* Tablet and Desktop */
@media (min-width: 768px) {
    #card-container {
        padding: 40px;
        max-width: 800px;
        margin: 0 auto;
    }

    .question-text {
        font-size: 1.5rem;
    }

    .answer-option {
        font-size: 1.1rem;
        padding: 20px;
    }

    #progress-text {
        font-size: 0.9rem;
        padding: 6px 12px;
    }

    .score-item {
        font-size: 1rem;
        padding: 8px 14px;
    }

    .btn {
        max-width: 200px;
    }

    #action-buttons {
        justify-content: center;
        gap: 12px;
        padding: 12px;
    }
}

/* Loading State */
.loading .card-front {
    opacity: 0.5;
    pointer-events: none;
}

/* Completion Screen */
.completion-screen {
    text-align: center;
    padding: 40px 20px;
}

.completion-screen h1 {
    font-size: 2rem;
    color: var(--primary-color);
    margin-bottom: 16px;
}

.completion-screen .final-score {
    font-size: 3rem;
    font-weight: 700;
    color: var(--success-color);
    margin: 20px 0;
}

.completion-screen .message {
    font-size: 1.1rem;
    color: var(--text-dark);
    line-height: 1.6;
}