/* Tinder-Style Russian Learning App */

* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
    -webkit-tap-highlight-color: transparent;
}

:root {
    --primary-color: #FF6B6B;
    --success-color: #51CF66;
    --bg-gradient-1: #667eea;
    --bg-gradient-2: #764ba2;
    --card-bg: #FFFFFF;
    --text-dark: #2C3E50;
    --text-light: #7F8C8D;
    --shadow: 0 8px 16px rgba(0, 0, 0, 0.15);
    --shadow-lg: 0 20px 40px rgba(0, 0, 0, 0.25);
}

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen, Ubuntu, Cantarell, sans-serif;
    background: linear-gradient(135deg, var(--bg-gradient-1) 0%, var(--bg-gradient-2) 100%);
    min-height: 100vh;
    color: var(--text-dark);
    overflow-x: hidden;
    touch-action: pan-y;
}

/* Progress Bar */
.progress-container {
    position: sticky;
    top: 0;
    background: white;
    padding: 15px;
    box-shadow: var(--shadow);
    z-index: 100;
}

.progress-info {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 10px;
}

.progress-text {
    font-size: 18px;
    font-weight: bold;
    color: var(--text-dark);
}

.stats {
    display: flex;
    gap: 15px;
}

.stat {
    display: flex;
    align-items: center;
    gap: 5px;
    font-weight: bold;
}

.stat-icon {
    font-size: 18px;
}

.progress-bar {
    width: 100%;
    height: 8px;
    background: #E0E0E0;
    border-radius: 10px;
    overflow: hidden;
}

.progress-fill {
    height: 100%;
    background: linear-gradient(90deg, var(--success-color), var(--bg-gradient-1));
    border-radius: 10px;
    transition: width 0.5s ease;
    width: 0%;
}

/* Container */
.container {
    max-width: 500px;
    margin: 0 auto;
    padding: 20px;
    min-height: calc(100vh - 120px);
}

/* Screens */
.screen {
    animation: fadeIn 0.5s ease;
}

.screen.hidden {
    display: none;
}

/* Welcome Screen */
.welcome-content {
    text-align: center;
    padding: 40px 20px;
}

.welcome-content h1 {
    font-size: 48px;
    color: white;
    margin-bottom: 10px;
    text-shadow: 2px 2px 4px rgba(0, 0, 0, 0.2);
}

.welcome-subtitle {
    font-size: 18px;
    color: rgba(255, 255, 255, 0.9);
    margin-bottom: 50px;
}

.mode-selection {
    display: flex;
    flex-direction: column;
    gap: 20px;
}

.mode-select-btn {
    background: white;
    border: none;
    border-radius: 20px;
    padding: 30px;
    cursor: pointer;
    transition: all 0.3s ease;
    box-shadow: var(--shadow);
}

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

.mode-icon {
    font-size: 48px;
    margin-bottom: 10px;
}

.mode-title {
    font-size: 24px;
    font-weight: bold;
    color: var(--text-dark);
    margin-bottom: 5px;
}

.mode-desc {
    font-size: 14px;
    color: var(--text-light);
}

/* Learning Screen */
.mode-indicator {
    text-align: center;
    color: white;
    font-size: 18px;
    font-weight: bold;
    padding: 10px;
    margin-bottom: 10px;
    background: rgba(255, 255, 255, 0.2);
    border-radius: 15px;
}

.swipe-instructions {
    display: flex;
    justify-content: space-between;
    margin-bottom: 20px;
    padding: 0 20px;
}

.instruction {
    display: flex;
    align-items: center;
    gap: 8px;
    font-weight: bold;
    color: white;
    font-size: 14px;
}

.instruction.left {
    color: rgba(255, 107, 107, 1);
}

.instruction.right {
    color: rgba(81, 207, 102, 1);
}

.arrow {
    font-size: 24px;
}

/* Cards Container */
.cards-container {
    position: relative;
    width: 100%;
    height: 550px;
    margin-bottom: 30px;
}

.swipe-card {
    position: absolute;
    width: 100%;
    height: 100%;
    background: white;
    border-radius: 25px;
    padding: 40px 30px;
    box-shadow: var(--shadow-lg);
    cursor: grab;
    user-select: none;
    transition: transform 0.3s ease, opacity 0.3s ease;
}

.swipe-card:active {
    cursor: grabbing;
}

.swipe-card.top-card {
    z-index: 10;
}

.swipe-card.next-card {
    z-index: 5;
    transform: scale(0.95);
    opacity: 0.8;
}

.swipe-card.third-card {
    z-index: 1;
    transform: scale(0.9);
    opacity: 0.5;
}

/* Card swiping animations */
.swipe-card.swipe-left {
    transform: translateX(-150%) rotate(-30deg);
    opacity: 0;
}

.swipe-card.swipe-right {
    transform: translateX(150%) rotate(30deg);
    opacity: 0;
}

.swipe-card.removing {
    transition: transform 0.3s ease, opacity 0.3s ease;
}

/* Swipe indicators */
.swipe-indicator {
    position: absolute;
    top: 30px;
    font-size: 64px;
    font-weight: bold;
    opacity: 0;
    transition: opacity 0.2s;
    pointer-events: none;
}

.swipe-indicator.left {
    left: 30px;
    color: var(--primary-color);
}

.swipe-indicator.right {
    right: 30px;
    color: var(--success-color);
}

.swipe-card.show-left .swipe-indicator.left {
    opacity: 1;
}

.swipe-card.show-right .swipe-indicator.right {
    opacity: 1;
}

/* Card Content */
.card-sound-btn {
    position: absolute;
    top: 20px;
    right: 20px;
    background: linear-gradient(135deg, var(--bg-gradient-1), var(--bg-gradient-2));
    border: none;
    border-radius: 50%;
    width: 50px;
    height: 50px;
    font-size: 24px;
    cursor: pointer;
    box-shadow: 0 4px 8px rgba(0, 0, 0, 0.2);
    transition: all 0.3s ease;
}

.card-sound-btn:active {
    transform: scale(0.9);
}

.card-russian {
    text-align: center;
    font-size: 56px;
    font-weight: bold;
    color: var(--text-dark);
    margin: 60px 0 40px 0;
}

.card-question {
    text-align: center;
    font-size: 20px;
    color: var(--text-light);
    margin-bottom: 20px;
}

.card-answer {
    text-align: center;
    font-size: 32px;
    font-weight: bold;
    color: var(--success-color);
    margin-bottom: 20px;
    padding: 20px;
    background: rgba(81, 207, 102, 0.1);
    border-radius: 15px;
    border: 2px solid var(--success-color);
}

.card-options {
    display: flex;
    flex-direction: column;
    gap: 15px;
}

.card-option {
    padding: 18px 20px;
    background: #F8F9FA;
    border: 2px solid #E9ECEF;
    border-radius: 15px;
    font-size: 18px;
    font-weight: 600;
    color: var(--text-dark);
    text-align: center;
    transition: all 0.2s ease;
}

.card-option.correct {
    background: var(--success-color);
    color: white;
    border-color: var(--success-color);
}

.card-option.wrong {
    background: var(--primary-color);
    color: white;
    border-color: var(--primary-color);
}

/* Complete Message */
.complete-message {
    background: white;
    border-radius: 25px;
    padding: 40px;
    text-align: center;
    box-shadow: var(--shadow-lg);
}

.complete-message.hidden {
    display: none;
}

.complete-message h2 {
    font-size: 36px;
    color: var(--text-dark);
    margin-bottom: 15px;
}

.complete-message p {
    font-size: 18px;
    color: var(--text-light);
    margin-bottom: 30px;
}

.score-summary {
    display: flex;
    flex-direction: column;
    gap: 15px;
    margin-bottom: 30px;
}

.score-item {
    display: flex;
    justify-content: space-between;
    padding: 15px 20px;
    background: #F8F9FA;
    border-radius: 12px;
    font-size: 18px;
}

.score-label {
    font-weight: 600;
    color: var(--text-light);
}

.score-value {
    font-weight: bold;
    font-size: 24px;
    color: var(--text-dark);
}

.exam-btn {
    width: 100%;
    padding: 18px;
    border: none;
    background: linear-gradient(135deg, var(--bg-gradient-1), var(--bg-gradient-2));
    color: white;
    border-radius: 15px;
    font-size: 20px;
    font-weight: bold;
    cursor: pointer;
    transition: all 0.3s ease;
}

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

/* Exam Screen */
.exam-header {
    text-align: center;
    margin-bottom: 30px;
    color: white;
}

.exam-header h2 {
    font-size: 32px;
    margin-bottom: 10px;
}

.exam-progress {
    font-size: 18px;
    font-weight: 600;
}

.exam-card {
    background: white;
    border-radius: 25px;
    padding: 40px 30px;
    box-shadow: var(--shadow-lg);
    margin-bottom: 30px;
    position: relative;
}

.sound-btn-exam {
    position: absolute;
    top: 20px;
    right: 20px;
    background: linear-gradient(135deg, var(--bg-gradient-1), var(--bg-gradient-2));
    border: none;
    border-radius: 50%;
    width: 50px;
    height: 50px;
    font-size: 24px;
    cursor: pointer;
    box-shadow: 0 4px 8px rgba(0, 0, 0, 0.2);
    transition: all 0.3s ease;
}

.sound-btn-exam:active {
    transform: scale(0.9);
}

.exam-question {
    text-align: center;
    font-size: 32px;
    font-weight: bold;
    color: var(--text-dark);
    margin-bottom: 40px;
    padding-right: 60px;
}

.exam-options {
    display: flex;
    flex-direction: column;
    gap: 15px;
}

.exam-option {
    padding: 18px 20px;
    background: #F8F9FA;
    border: 2px solid #E9ECEF;
    border-radius: 15px;
    font-size: 18px;
    font-weight: 600;
    color: var(--text-dark);
    text-align: center;
    cursor: pointer;
    transition: all 0.2s ease;
}

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

.exam-option.correct {
    background: var(--success-color);
    color: white;
    border-color: var(--success-color);
}

.exam-option.wrong {
    background: var(--primary-color);
    color: white;
    border-color: var(--primary-color);
}

.exam-option.disabled {
    cursor: not-allowed;
    opacity: 0.6;
}

/* Exam Complete */
.exam-complete {
    background: white;
    border-radius: 25px;
    padding: 40px;
    text-align: center;
    box-shadow: var(--shadow-lg);
}

.exam-complete.hidden {
    display: none;
}

.exam-result h2 {
    font-size: 32px;
    color: var(--text-dark);
    margin-bottom: 30px;
}

.exam-score {
    margin-bottom: 30px;
}

.big-score {
    font-size: 72px;
    font-weight: bold;
    color: var(--text-dark);
    margin-bottom: 10px;
}

.exam-percentage {
    font-size: 36px;
    font-weight: 600;
    color: var(--success-color);
}

.exam-message {
    font-size: 20px;
    color: var(--text-light);
    margin-bottom: 30px;
    line-height: 1.6;
}

.restart-btn {
    width: 100%;
    padding: 18px;
    border: none;
    background: linear-gradient(135deg, var(--bg-gradient-1), var(--bg-gradient-2));
    color: white;
    border-radius: 15px;
    font-size: 20px;
    font-weight: bold;
    cursor: pointer;
    transition: all 0.3s ease;
}

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

/* Animations */
@keyframes fadeIn {
    from {
        opacity: 0;
    }
    to {
        opacity: 1;
    }
}

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

/* Utility */
.hidden {
    display: none !important;
}

/* Responsive */
@media (max-width: 480px) {
    .card-russian {
        font-size: 48px;
    }

    .exam-question {
        font-size: 28px;
    }

    .big-score {
        font-size: 56px;
    }
}