:root {
    /* Light Theme Colors */
    --light-bg: #f5f5f5;
    --light-surface: #ffffff;
    --light-text: #333333;
    --light-text-secondary: #666666;
    --light-border: #e0e0e0;
    --light-accent: #4285f4; /* Google Blue */
    --light-accent-hover: #3367d6;
    --light-danger: #ea4335; /* Google Red */
    --light-success: #34a853; /* Google Green */
    --light-input-bg: #f8f8f8;
    
    /* Dark Theme Colors */
    --dark-bg: #121212;
    --dark-surface: #1e1e1e;
    --dark-text: #f5f5f5;
    --dark-text-secondary: #b0b0b0;
    --dark-border: #333333;
    --dark-accent: #4285f4;
    --dark-accent-hover: #5c9aff;
    --dark-danger: #ff6b6b;
    --dark-success: #4cd964;
    --dark-input-bg: #2a2a2a;
    
    /* Common Variables */
    --border-radius: 8px;
    --box-shadow: 0 4px 6px rgba(0, 0, 0, 0.1);
    --transition: all 0.3s ease;
}

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

body {
    transition: var(--transition);
}

.light-theme {
    background-color: var(--light-bg);
    color: var(--light-text);
}

.dark-theme {
    background-color: var(--dark-bg);
    color: var(--dark-text);
}

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

header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 30px;
    flex-wrap: wrap;
    gap: 20px;
}

header h1 {
    display: flex;
    align-items: center;
    gap: 10px;
    font-size: 28px;
}

.theme-toggle {
    cursor: pointer;
    width: 40px;
    height: 40px;
    display: flex;
    align-items: center;
    justify-content: center;
    border-radius: 50%;
    background-color: var(--light-surface);
    box-shadow: var(--box-shadow);
    transition: var(--transition);
}

.theme-toggle:hover {
    transform: translateY(-3px);
}

.dark-theme .theme-toggle {
    background-color: var(--dark-surface);
}

.theme-toggle i {
    font-size: 22px;
    color: var(--light-accent);
    transition: var(--transition);
}

.dark-theme .theme-toggle i {
    color: var(--dark-accent);
}

main {
    display: grid;
    grid-template-columns: 1fr;
    gap: 30px;
}

.upload-section, .files-section, .options-section, .status-section, .pages-section {
    background-color: var(--light-surface);
    border-radius: var(--border-radius);
    padding: 20px;
    box-shadow: var(--box-shadow);
    transition: var(--transition);
}

.dark-theme .upload-section,
.dark-theme .files-section,
.dark-theme .options-section,
.dark-theme .status-section,
.dark-theme .pages-section {
    background-color: var(--dark-surface);
}

.drop-area {
    border: 2px dashed var(--light-border);
    border-radius: var(--border-radius);
    padding: 40px 20px;
    text-align: center;
    cursor: pointer;
    transition: var(--transition);
    background-color: var(--light-input-bg);
}

.dark-theme .drop-area {
    border-color: var(--dark-border);
    background-color: var(--dark-input-bg);
}

.drop-area.highlight {
    border-color: var(--light-accent);
    background-color: rgba(66, 133, 244, 0.05);
}

.dark-theme .drop-area.highlight {
    border-color: var(--dark-accent);
    background-color: rgba(92, 154, 255, 0.1);
}

.upload-icon {
    font-size: 48px;
    color: var(--light-accent);
    margin-bottom: 10px;
}

.dark-theme .upload-icon {
    color: var(--dark-accent);
}

.file-input-button {
    display: inline-flex;
    align-items: center;
    gap: 8px;
    background-color: var(--light-accent);
    color: white;
    border: none;
    border-radius: var(--border-radius);
    padding: 10px 20px;
    cursor: pointer;
    margin-top: 15px;
    transition: var(--transition);
    font-weight: 500;
}

.file-input-button:hover {
    background-color: var(--light-accent-hover);
    transform: translateY(-2px);
    box-shadow: 0 4px 8px rgba(0, 0, 0, 0.15);
}

.dark-theme .file-input-button {
    background-color: var(--dark-accent);
}

.dark-theme .file-input-button:hover {
    background-color: var(--dark-accent-hover);
}

.files-section h2, .options-section h2, .pages-section h2 {
    margin-bottom: 15px;
    font-size: 20px;
    display: flex;
    align-items: center;
    gap: 10px;
}

.files-section h2::before {
    content: "\e2c7";
    font-family: 'Material Icons';
    color: var(--light-accent);
}

.options-section h2::before {
    content: "\e8b8";
    font-family: 'Material Icons';
    color: var(--light-accent);
}

.pages-section h2::before {
    content: "\e3f4";
    font-family: 'Material Icons';
    color: var(--light-accent);
}

.dark-theme .files-section h2::before,
.dark-theme .options-section h2::before,
.dark-theme .pages-section h2::before {
    color: var(--dark-accent);
}

.file-list {
    display: flex;
    flex-direction: column;
    gap: 10px;
    margin-bottom: 20px;
}

.file-item {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 10px 15px;
    background-color: var(--light-input-bg);
    border-radius: var(--border-radius);
    transition: var(--transition);
}

.file-item:hover {
    transform: translateX(5px);
    box-shadow: 0 2px 5px rgba(0, 0, 0, 0.1);
}

.dark-theme .file-item {
    background-color: var(--dark-input-bg);
}

.file-info {
    display: flex;
    align-items: center;
    gap: 10px;
}

.file-icon {
    color: var(--light-accent);
}

.dark-theme .file-icon {
    color: var(--dark-accent);
}

.file-name {
    word-break: break-all;
}

.delete-file {
    color: var(--light-danger);
    cursor: pointer;
    transition: var(--transition);
}

.delete-file:hover {
    transform: scale(1.1);
}

.dark-theme .delete-file {
    color: var(--dark-danger);
}

.pages-container {
    max-height: 600px;
    overflow-y: auto;
    margin-bottom: 20px;
    padding-right: 10px;
}

.pages-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(200px, 1fr));
    gap: 20px;
}

.page-card {
    background-color: var(--light-input-bg);
    border-radius: var(--border-radius);
    overflow: hidden;
    transition: var(--transition);
    box-shadow: 0 2px 4px rgba(0, 0, 0, 0.1);
}

.dark-theme .page-card {
    background-color: var(--dark-input-bg);
}

.page-card:hover {
    transform: translateY(-5px);
    box-shadow: 0 5px 15px rgba(0, 0, 0, 0.1);
}

.page-image {
    width: 100%;
    height: 250px;
    object-fit: contain;
    background-color: white;
    border-bottom: 1px solid var(--light-border);
}

.dark-theme .page-image {
    background-color: #2a2a2a;
    border-color: var(--dark-border);
}

.page-details {
    padding: 12px;
}

.page-title {
    font-weight: 500;
    margin-bottom: 5px;
    font-size: 14px;
}

.page-subtitle {
    font-size: 12px;
    color: var(--light-text-secondary);
    margin-bottom: 10px;
}

.dark-theme .page-subtitle {
    color: var(--dark-text-secondary);
}

.download-btn {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 5px;
    width: 100%;
    padding: 8px;
    background-color: var(--light-accent);
    color: white;
    border: none;
    border-radius: var(--border-radius);
    cursor: pointer;
    transition: var(--transition);
    font-size: 13px;
}

.download-btn:hover {
    background-color: var(--light-accent-hover);
    transform: translateY(-2px);
}

.dark-theme .download-btn {
    background-color: var(--dark-accent);
}

.dark-theme .download-btn:hover {
    background-color: var(--dark-accent-hover);
}

.option-group {
    display: flex;
    align-items: center;
    gap: 15px;
    margin-bottom: 20px;
}

select {
    padding: 10px 12px;
    border-radius: var(--border-radius);
    border: 1px solid var(--light-border);
    background-color: var(--light-input-bg);
    color: var(--light-text);
    transition: var(--transition);
    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%23666%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, repeat;
    background-position: right 10px top 50%, 0 0;
    background-size: 12px auto, 100%;
    padding-right: 30px;
    cursor: pointer;
}

select:focus {
    outline: none;
    border-color: var(--light-accent);
    box-shadow: 0 0 0 2px rgba(66, 133, 244, 0.2);
}

.dark-theme select {
    background-color: var(--dark-input-bg);
    border-color: var(--dark-border);
    color: var(--dark-text);
    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%23b0b0b0%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");
}

.dark-theme select:focus {
    border-color: var(--dark-accent);
    box-shadow: 0 0 0 2px rgba(66, 133, 244, 0.3);
}

.primary-btn, .secondary-btn {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 8px;
    border: none;
    border-radius: var(--border-radius);
    padding: 12px 20px;
    cursor: pointer;
    transition: var(--transition);
    font-weight: 500;
    width: 100%;
}

.primary-btn {
    background-color: var(--light-accent);
    color: white;
}

.secondary-btn {
    background-color: var(--light-input-bg);
    color: var(--light-text);
    border: 1px solid var(--light-border);
}

.primary-btn:hover, .secondary-btn:hover {
    transform: translateY(-3px);
    box-shadow: 0 4px 8px rgba(0, 0, 0, 0.15);
}

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

.secondary-btn:hover {
    background-color: var(--light-bg);
}

.primary-btn:disabled, .secondary-btn:disabled {
    background-color: var(--light-border);
    cursor: not-allowed;
    opacity: 0.7;
    transform: none;
    box-shadow: none;
}

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

.dark-theme .secondary-btn {
    background-color: var(--dark-input-bg);
    color: var(--dark-text);
    border-color: var(--dark-border);
}

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

.dark-theme .secondary-btn:hover {
    background-color: var(--dark-bg);
}

.dark-theme .primary-btn:disabled, .dark-theme .secondary-btn:disabled {
    background-color: var(--dark-border);
}

.status-section, .pages-section {
    display: none;
}

.status-message {
    text-align: center;
    margin-bottom: 15px;
    font-weight: 500;
    padding: 10px;
    border-radius: var(--border-radius);
    background-color: var(--light-input-bg);
}

.dark-theme .status-message {
    background-color: var(--dark-input-bg);
}

.progress-bar {
    height: 10px;
    background-color: var(--light-border);
    border-radius: 5px;
    overflow: hidden;
}

.dark-theme .progress-bar {
    background-color: var(--dark-border);
}

.progress {
    height: 100%;
    background-color: var(--light-success);
    width: 0%;
    transition: width 0.3s ease;
}

.dark-theme .progress {
    background-color: var(--dark-success);
}

/* File group header */
.file-group-header {
    grid-column: 1 / -1;
    background-color: var(--light-input-bg);
    padding: 10px 15px;
    border-radius: var(--border-radius);
    margin-bottom: 10px;
    font-weight: 500;
    display: flex;
    align-items: center;
    gap: 10px;
}

.dark-theme .file-group-header {
    background-color: var(--dark-input-bg);
}

/* Custom scrollbar for pages container */
.pages-container::-webkit-scrollbar {
    width: 8px;
}

.pages-container::-webkit-scrollbar-track {
    background: var(--light-bg);
    border-radius: 4px;
}

.pages-container::-webkit-scrollbar-thumb {
    background-color: var(--light-border);
    border-radius: 4px;
}

.pages-container::-webkit-scrollbar-thumb:hover {
    background-color: var(--light-text-secondary);
}

.dark-theme .pages-container::-webkit-scrollbar-track {
    background: var(--dark-bg);
}

.dark-theme .pages-container::-webkit-scrollbar-thumb {
    background-color: var(--dark-border);
}

.dark-theme .pages-container::-webkit-scrollbar-thumb:hover {
    background-color: var(--dark-text-secondary);
}

/* Responsive Design */
@media (max-width: 768px) {
    .container {
        padding: 15px;
    }
    
    header h1 {
        font-size: 22px;
    }
    
    .drop-area {
        padding: 30px 15px;
    }
    
    .upload-icon {
        font-size: 36px;
    }
    
    .option-group {
        flex-direction: column;
        align-items: flex-start;
        gap: 8px;
    }
    
    select {
        width: 100%;
    }
    
    .pages-grid {
        grid-template-columns: repeat(auto-fill, minmax(150px, 1fr));
        gap: 15px;
    }
    
    .page-image {
        height: 200px;
    }
}

@media (min-width: 992px) {
    main {
        grid-template-columns: 1fr 1fr;
        grid-template-areas: 
            "upload options"
            "files files"
            "status status"
            "pages pages";
        gap: 20px;
    }
    
    .upload-section {
        grid-area: upload;
    }
    
    .options-section {
        grid-area: options;
    }
    
    .files-section {
        grid-area: files;
    }
    
    .status-section {
        grid-area: status;
    }
    
    .pages-section {
        grid-area: pages;
    }
}

/* Animation effects */
@keyframes fadeIn {
    from { opacity: 0; transform: translateY(10px); }
    to { opacity: 1; transform: translateY(0); }
}

.upload-section, .files-section, .options-section, .status-section, .pages-section {
    animation: fadeIn 0.5s ease-out;
}