/* Global Styles */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
    font-family: 'Poppins', sans-serif;
}

:root {
    --primary-color: #2196F3;
    --primary-dark: #1976D2;
    --secondary-color: #9E9E9E;
    --success-color: #4CAF50;
    --danger-color: #F44336;
    --warning-color: #FFC107;
    --light-color: #f8f9fa;
    --dark-color: #333333;
    --border-radius: 12px;
    --box-shadow: 0 8px 32px rgba(0, 0, 0, 0.1);
    --transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
    /* New variables for better theming */
    --btn-gradient-start: #2196F3;
    --btn-gradient-end: #4CAF50;
    --btn-hover-shade: rgba(0,0,0,0.06);
    --correct-color: #2e7d32; /* text color for correct */
    --correct-bg: #e8f5e9; /* background for correct */
    --incorrect-color: #c62828; /* text color for incorrect */
    --incorrect-bg: #ffebee; /* background for incorrect */
    --feedback-success-bg: #d4edda;
    --feedback-success-text: #155724;
    --feedback-error-bg: #f8d7da;
    --feedback-error-text: #721c24;
}

/* Base Styles */
html, body {
    height: 100%;
    margin: 0;
    padding: 0;
    -webkit-text-size-adjust: 100%;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
}

body {
    background: linear-gradient(135deg, #f5f7fa 0%, #c3cfe2 100%);
    min-height: 100vh;
    margin: 0;
    padding: 0;
    font-family: 'Poppins', sans-serif;
    color: var(--dark-color);
    line-height: 1.6;
    overflow-x: hidden;
}

.container {
    background: white;
    border-radius: var(--border-radius);
    box-shadow: var(--box-shadow);
    width: 100%;
    max-width: 800px;
    min-height: 100vh;
    margin: 0 auto;
    padding: 0;
    position: relative;
    overflow: hidden;
    border: 1px solid rgba(255, 255, 255, 0.5);
}

.screen {
    display: none;
    animation: fadeIn 0.5s ease;
}

.screen.active {
    display: block;
}

h1 {
    color: white;
    text-align: center;
    margin: 0;
    padding: 1.5rem;
    font-size: 2rem;
    font-weight: 700;
    background: linear-gradient(135deg, #2196F3 0%, #1976D2 100%);
    position: relative;
    box-shadow: 0 2px 10px rgba(0, 0, 0, 0.1);
}

h2 {
    color: var(--dark-color);
    margin: 1.5rem 2rem;
    font-size: 1.5rem;
    font-weight: 600;
    line-height: 1.4;
}

#start-btn {
    margin-top: 2rem;
    padding: 1rem 3rem;
    font-size: 1.2rem;
    font-weight: 600;
    min-width: 200px;
    height: auto;
    min-height: 50px;
    display: inline-flex;
    align-items: center;
    justify-content: center;
}

#submit-btn, #next-btn {
    padding: 12px 24px;
    font-size: 1rem;
    font-weight: 600;
    border-radius: 50px;
    cursor: pointer;
    transition: all 0.3s ease;
    min-width: 120px;
    min-height: 50px;
    text-align: center;
    border: none;
    flex: 1;
    display: inline-flex;
    align-items: center;
    justify-content: center;
    white-space: nowrap;
}

/* Start Screen */
#start-screen {
    text-align: center;
    padding: 2rem;
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    min-height: 100vh;
    box-sizing: border-box;
}

.category-selector {
    margin: 2rem 0 3rem;
    padding: 0 1.5rem;
}

#category {
    padding: 1rem;
    border-radius: 50px;
    border: 2px solid #e1e5ee;
    font-size: 1rem;
    margin-top: 1rem;
    width: 100%;
    max-width: 400px;
    transition: var(--transition);
    background: white;
    appearance: none;
    -webkit-appearance: none;
    -moz-appearance: none;
    background-image: url("data:image/svg+xml;charset=US-ASCII,%3Csvg%20xmlns%3D%22http%3A%2F%2Fwww.w3.org%2F2000%2Fsvg%22%20width%3D%22292.4%22%20height%3D%22292.4%22%3E%3Cpath%20fill%3D%22%232196F3%22%20d%3D%22M287%2069.4a17.6%2017.6%200%200%200-13-5.4H18.4c-5%200-9.3%201.8-12.9%205.4A17.6%2017.6%200%200%200%200%2082.2c0%205%201.8%209.3%205.4%2012.9l128%20127.9c3.6%203.6%207.8%205.4%2012.8%205.4s9.2-1.8%2012.8-5.4L287%2095c3.5-3.5%205.4-7.8%205.4-12.8%200-5-1.9-9.2-5.5-12.8z%22%2F%3E%3C%2Fsvg%3E");
    background-repeat: no-repeat;
    background-position: right 1rem top 50%;
    background-size: 12px auto;
    padding-right: 2.5rem;
    cursor: pointer;
    text-align: center;
    font-weight: 500;
}

#category:focus {
    outline: none;
    border-color: var(--primary-color);
    box-shadow: 0 0 0 3px rgba(33, 150, 243, 0.2);
}

/* Quiz Screen */
#quiz-screen {
    padding-bottom: 100px; /* Space for fixed navigation */
    min-height: 100vh;
    box-sizing: border-box;
    position: relative;
    overflow-y: auto;
}

.quiz-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 1.5rem 2rem;
    background: #f8f9fa;
    border-bottom: 1px solid #e9ecef;
}

.timer, .score {
    background: white;
    padding: 0.5rem 1.2rem;
    border-radius: 50px;
    font-weight: 600;
    box-shadow: 0 2px 8px rgba(0, 0, 0, 0.08);
    display: flex;
    align-items: center;
    gap: 0.5rem;
    font-size: 1rem;
}

.timer {
    color: var(--danger-color);
    border: 1px solid #ffebee;
}

.score {
    color: var(--primary-color);
    border: 1px solid #e3f2fd;
}

.progress-container {
    position: relative;
    height: 8px;
    background: #e9ecef;
    overflow: hidden;
    margin: 0;
    border-radius: 0;
    width: 100%;
}

#progress-bar {
    height: 100%;
    width: 0%;
    background: linear-gradient(90deg, var(--primary-color) 0%, var(--primary-dark) 100%);
    transition: width 0.5s ease, box-shadow 0.3s ease;
    position: relative;
    overflow: hidden;
    border-radius: 8px;
    box-shadow: 0 4px 12px rgba(33, 150, 243, 0.12) inset;
}

#progress-bar::after {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: linear-gradient(90deg, 
        transparent 0%, 
        rgba(255, 255, 255, 0.25) 50%, 
        transparent 100%);
    animation: shimmer 2s infinite;
}

@keyframes shimmer {
    0% { transform: translateX(-100%); }
    100% { transform: translateX(100%); }
}

#question-container {
    padding: 2rem;
    margin-bottom: 20px; /* Add margin to prevent content from being hidden */
}

.options {
    display: grid;
    grid-template-columns: 1fr;
    gap: 1rem;
    margin: 2rem 0;
}

.option {
    background: white;
    border: 2px solid #e9ecef;
    border-radius: 12px;
    padding: 1.2rem 1.5rem;
    cursor: pointer;
    transition: var(--transition);
    text-align: left;
    font-size: 1rem;
    font-weight: 500;
    color: #495057;
    position: relative;
    overflow: hidden;
    box-shadow: 0 2px 8px rgba(0, 0, 0, 0.05);
}

.option::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    width: 4px;
    height: 100%;
    background: transparent;
    transition: var(--transition);
}

.option:hover {
    background: #f8f9fa;
    border-color: #b3d7ff;
    transform: translateY(-2px);
    box-shadow: 0 4px 12px rgba(0, 0, 0, 0.1);
}

.option.selected {
    background: linear-gradient(90deg, rgba(33,150,243,0.06), rgba(76,175,80,0.03));
    border-color: var(--primary-color);
    color: var(--primary-dark);
    font-weight: 600;
}

.option.selected::before {
    background: var(--primary-color);
}

.option.correct {
    background: var(--correct-bg);
    border-color: var(--success-color);
    color: var(--correct-color);
    font-weight: 700;
    box-shadow: 0 6px 18px rgba(76,175,80,0.08);
}

.option.correct::before {
    background: var(--success-color);
}

.option.wrong {
    background: var(--incorrect-bg);
    border-color: var(--danger-color);
    color: var(--incorrect-color);
    text-decoration: none;
    opacity: 1;
    box-shadow: 0 6px 18px rgba(244,67,54,0.06);
}

.option.wrong::before {
    background: var(--danger-color);
}

/* Navigation Buttons */
.navigation {
    display: flex;
    justify-content: center;
    align-items: center;
    gap: 1.5rem;
    padding: 1.5rem 2rem;
    background: rgba(248,249,250,0.95);
    border-top: 1px solid #e9ecef;
    position: fixed;
    bottom: 0;
    left: 0;
    right: 0;
    z-index: 1000;
    box-shadow: 0 -4px 24px rgba(33, 150, 243, 0.10);
    backdrop-filter: blur(8px);
    border-radius: 16px 16px 0 0;
    transition: background 0.3s;
}

/* Mobile Styles */
@media (max-width: 768px) {
    body {
        padding: 10px;
    }
    
    .container {
        border-radius: 8px;
        overflow: hidden;
        margin: 0;
    }
    
    h1 {
        font-size: 1.5rem;
        padding: 1.2rem;
    }
    
    h2 {
        font-size: 1.3rem;
        margin: 1.2rem 1.5rem;
    }
    
    .quiz-header {
        flex-direction: column;
        align-items: stretch;
        gap: 1rem;
        padding: 1.2rem;
    }
    
    #question-container {
        padding: 1.5rem;
    }
    
    .options {
        gap: 0.8rem;
        margin: 1.5rem 0;
    }
    
    .option {
        padding: 1rem 1.2rem;
    }
    
    .navigation {
        flex-direction: column;
        gap: 12px;
        padding: 15px 10px;
        border-radius: 16px 16px 0 0;
        box-shadow: 0 -4px 24px rgba(33, 150, 243, 0.12);
    }
    
    #submit-btn, #next-btn {
        width: 100%;
        margin: 5px 0;
    }
    
    #quiz-screen {
        padding-bottom: 180px; /* Extra space for stacked buttons */
    }
}

.btn {
    min-width: 180px;
    max-width: 260px;
    width: 100%;
    margin: 0 8px;
    background: linear-gradient(135deg, var(--btn-gradient-start) 60%, var(--btn-gradient-end) 100%);
    box-shadow: 0 8px 32px rgba(33, 150, 243, 0.18), 0 1.5px 8px rgba(76,175,80,0.08);
    border-radius: 16px;
    font-size: 1.08rem;
    font-weight: 700;
    letter-spacing: 0.5px;
    transition: var(--transition), box-shadow 0.3s, transform 0.2s;
    position: relative;
    overflow: hidden;
    outline: none;
}

.btn:hover, .btn:focus {
    transform: scale(1.04);
    box-shadow: 0 16px 40px rgba(33, 150, 243, 0.22), 0 2px 12px rgba(76,175,80,0.12);
    background: linear-gradient(135deg, var(--btn-gradient-end) 0%, var(--btn-gradient-start) 100%);
}

.btn:active {
    transform: scale(0.98);
    box-shadow: 0 4px 12px rgba(33, 150, 243, 0.14);
}

.btn:focus {
    animation: btn-pulse 0.7s;
}

@keyframes btn-pulse {
    0% { box-shadow: 0 0 0 0 rgba(33,150,243,0.18); }
    50% { box-shadow: 0 0 0 12px rgba(33,150,243,0.10); }
    100% { box-shadow: 0 0 0 0 rgba(33,150,243,0.18); }
}

/* Feedback */
.feedback {
    margin-top: 1rem;
    padding: 1rem;
    border-radius: 12px;
    font-weight: 600;
    animation: feedback-pop 0.35s cubic-bezier(0.2, 0.8, 0.2, 1);
    box-shadow: 0 8px 24px rgba(0,0,0,0.06);
}

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

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

@keyframes feedback-pop {
    0% { transform: translateY(6px) scale(0.98); opacity: 0; }
    100% { transform: translateY(0) scale(1); opacity: 1; }
}

/* Score circle improvements */
.score-circle {
    width: 180px;
    height: 180px;
    border-radius: 50%;
    background: conic-gradient(#e9ecef 0% 100%);
    margin: 0 auto 2.5rem;
    display: flex;
    align-items: center;
    justify-content: center;
    position: relative;
    box-shadow: 0 12px 40px rgba(0, 0, 0, 0.09);
    transition: transform 0.3s ease, box-shadow 0.3s ease;
}

.score-circle-inner {
    width: 150px;
    height: 150px;
    border-radius: 50%;
    background: linear-gradient(180deg, #ffffff, #fbfdff);
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    z-index: 1;
    box-shadow: inset 0 0 0 8px #f8f9fa;
}

.score-percent {
    font-size: 2.6rem;
    font-weight: 800;
    background: linear-gradient(135deg, var(--primary-color), var(--success-color));
    -webkit-background-clip: text;
    background-clip: text; /* added standard property for compatibility */
    -webkit-text-fill-color: transparent;
    line-height: 1.1;
    margin-bottom: 0.2rem;
    transition: transform 0.4s ease;
}

/* Subtle pulse when high score */
.score-circle.high { animation: pulse 1.2s ease-in-out infinite; }

/* Animations */
@keyframes fadeIn {
    from { opacity: 0; transform: translateY(20px); }
    to { opacity: 1; transform: translateY(0); }
}

/* Responsive Design */
@media (max-width: 768px) {
    body {
        padding: 10px 10px 80px; /* Add bottom padding for fixed navigation */
    }
    
    .container {
        border-radius: 8px;
        overflow: hidden;
        margin: 0;
    }
    
    h1 {
        font-size: 1.5rem;
        padding: 1.2rem;
    }
    
    h2 {
        font-size: 1.3rem;
        margin: 1.2rem 1.5rem;
    }
    
    .quiz-header {
        flex-direction: column;
        align-items: stretch;
        gap: 1rem;
        padding: 1.2rem;
    }
    
    .timer, .score {
        width: 100%;
        justify-content: center;
    }
    
    #question-container {
        padding: 1.5rem;
    }
    
    .options {
        gap: 0.8rem;
        margin: 1.5rem 0;
    }
    
    .option {
        padding: 1rem 1.2rem;
    }
    
    .navigation {
        flex-direction: column;
        gap: 0.8rem;
        padding: 1.2rem;
        position: fixed;
        bottom: 0;
        left: 0;
        right: 0;
        border-radius: 16px 16px 0 0;
        box-shadow: 0 -4px 24px rgba(33, 150, 243, 0.08);
    }
    
    .btn {
        width: 100%;
        padding: 0.9rem;
    }
    
    .result-details {
        padding: 1.5rem;
        margin: 1.5rem 0;
    }
    
    .score-circle {
        width: 130px;
        height: 130px;
    }
    
    .score-circle-inner {
        width: 110px;
        height: 110px;
    }
    
    .score-percent {
        font-size: 2rem;
    }
}

/* Additional Feedback */
.feedback {
    margin-top: 1rem;
    padding: 1rem;
    border-radius: var(--border-radius);
    font-weight: 500;
    animation: fadeIn 0.3s ease;
}

.feedback.correct {
    background: #d4edda;
    color: #155724;
}

.feedback.incorrect {
    background: #f8d7da;
    color: #721c24;
}