:root {
    --primary: #4361ee;
    --primary-dark: #3a56d4;
    --secondary: #7209b7;
    --light: #f8f9fa;
    --dark: #212529;
    --gray: #6c757d;
    --light-gray: #e9ecef;
    --success: #4bb543;
    --success-light: #5bc754;
    --border-radius: 8px;
    --shadow: 0 4px 12px rgba(0, 0, 0, 0.1);
    --transition: all 0.3s ease;
}

[data-theme="dark"] {
    --light: #1e1e1e;
    --dark: #f0f0f0;
    --light-gray: #2a2a2a;
    --gray: #a0a0a0;
    --shadow: 0 4px 12px rgba(0, 0, 0, 0.4);
    --primary: #5a75f5;
    --primary-dark: #4a65e5;
    --file-card-bg: #3a3a3a;
    --results-bg: #252525;
}

* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
}

body {
    background-color: var(--light);
    color: var(--dark);
    line-height: 1.6;
    transition: var(--transition);
    min-height: 100vh;
}

.theme-toggle {
    position: absolute;
    top: 85px; /* Moved down by 10px */
    right: 1.5rem;
    background: none;
    border: none;
    color: var(--text-color);
    cursor: pointer;
    font-size: 1.5rem;
    padding: 0.5rem;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    width: 3rem;
    height: 3rem;
    box-shadow: var(--shadow);
    transition: var(--transition);
    background-color: var(--light);
    color: var(--dark);
    z-index: 100;
}

.theme-toggle:hover {
    /* No hover effect */
}

.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 20px;
}

.hero {
    padding: 60px 0 40px;
    text-align: center;
    max-width: 800px;
    margin: 0 auto;
}

.hero h1 {
    font-size: 3rem;
    margin-bottom: 20px;
    color: var(--primary);
}

.hero p {
    font-size: 1.2rem;
    color: var(--gray);
    margin-bottom: 40px;
}

.upload-area {
    border: 2px dashed var(--primary);
    border-radius: var(--border-radius);
    padding: 60px 20px;
    text-align: center;
    cursor: pointer;
    transition: var(--transition);
    background-color: rgba(67, 97, 238, 0.05);
    margin-bottom: 30px;
}

.upload-area:hover {
    background-color: rgba(67, 97, 238, 0.1);
}

.upload-area i {
    font-size: 3rem;
    color: var(--primary);
    margin-bottom: 20px;
}

.upload-area h3 {
    margin-bottom: 10px;
    color: var(--dark);
}

.upload-area p {
    color: var(--gray);
    margin-bottom: 20px;
}

.btn {
    background-color: var(--primary);
    color: white;
    border: none;
    padding: 12px 24px;
    border-radius: var(--border-radius);
    font-size: 1rem;
    font-weight: 600;
    cursor: pointer;
    transition: var(--transition);
    display: inline-flex;
    align-items: center;
    gap: 8px;
}

.btn:hover {
    background-color: var(--primary-dark);
}

.btn-success {
    background: linear-gradient(135deg, var(--success), var(--success-light));
    color: white;
}

.btn-success:hover {
    background: linear-gradient(135deg, var(--success-light), var(--success));
    transform: translateY(-2px);
    box-shadow: 0 6px 15px rgba(75, 181, 67, 0.4);
}

.btn-secondary {
    background-color: var(--light-gray);
    color: var(--dark);
}

.btn-secondary:hover {
    background-color: var(--gray);
    color: white;
}

.file-input {
    display: none;
}

.results {
    display: none;
    background-color: var(--light-gray);
    padding: 30px;
    border-radius: var(--border-radius);
    margin-top: 30px;
    box-shadow: var(--shadow);
}

[data-theme="dark"] .results {
    background-color: var(--results-bg);
}

.results.active {
    display: block;
}

.file-info {
    display: flex;
    justify-content: space-between;
    margin-bottom: 20px;
    flex-wrap: wrap;
    gap: 15px;
}

.file-card {
    background-color: var(--light);
    padding: 20px;
    border-radius: var(--border-radius);
    flex: 1;
    min-width: 200px;
    text-align: center;
    box-shadow: var(--shadow);
}

[data-theme="dark"] .file-card {
    background-color: var(--file-card-bg);
}

.file-card h4 {
    margin-bottom: 10px;
    color: var(--dark);
}

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

.compression-ratio {
    font-size: 1.2rem;
    color: var(--success);
    margin-top: 10px;
}

.action-buttons {
    display: flex;
    gap: 15px;
    justify-content: center;
    margin-top: 20px;
}

section {
    padding: 40px 0;
}

.section-title {
    text-align: center;
    margin-bottom: 40px;
    color: var(--dark);
}

.section-title h2 {
    font-size: 2rem;
    margin-bottom: 15px;
}

.section-title p {
    color: var(--gray);
    max-width: 600px;
    margin: 0 auto;
}

.features-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: 15px;
}

.feature-card {
    background-color: white;
    padding: 25px;
    border-radius: var(--border-radius);
    text-align: center;
    box-shadow: 0 8px 20px rgba(0, 0, 0, 0.15);
    transition: var(--transition);
}

[data-theme="dark"] .feature-card {
    background-color: var(--light-gray);
    box-shadow: var(--shadow);
}

.feature-card:hover {
    transform: translateY(-5px);
}

.feature-icon {
    font-size: 2.5rem;
    color: var(--primary);
    margin-bottom: 20px;
}

.feature-card h3 {
    margin-bottom: 15px;
    color: var(--dark);
}

.feature-card p {
    color: var(--gray);
}

.faq-item {
    margin-bottom: 15px;
    border-radius: var(--border-radius);
    overflow: hidden;
    box-shadow: var(--shadow);
}

.faq-question {
    background-color: var(--light-gray);
    padding: 20px;
    cursor: pointer;
    display: flex;
    justify-content: space-between;
    align-items: center;
    transition: var(--transition);
}

.faq-question:hover {
    background-color: var(--primary);
    color: white;
}

.faq-question h3 {
    font-size: 1.1rem;
    font-weight: 600;
}

.faq-answer {
    background-color: var(--light);
    padding: 0;
    max-height: 0;
    overflow: hidden;
    transition: max-height 0.3s ease, padding 0.3s ease;
}

.faq-answer.active {
    padding: 20px;
    max-height: 500px;
}

.faq-answer p {
    color: var(--gray);
}

.about-content {
    max-width: 800px;
    margin: 0 auto;
}

.about-content p {
    margin-bottom: 20px;
    color: var(--dark);
}

@media (max-width: 768px) {
    .hero h1 {
        font-size: 2.5rem;
    }
    
    .file-info {
        flex-direction: column;
    }
    
    .action-buttons {
        flex-direction: column;
    }
    
    .btn {
        width: 100%;
        justify-content: center;
    }
    
    .features-grid {
        gap: 15px;
    }
    
    .theme-toggle {
        top: 70px; /* Moved down by 10px for mobile */
    }
}