/* CSS Variables */
:root {
    --primary-color: #4f46e5;
    --primary-hover: #4338ca;
    --secondary-color: #6b7280;
    --success-color: #10b981;
    --error-color: #ef4444;
    --background: #f8fafc;
    --surface: #ffffff;
    --text-primary: #1e293b;
    --text-secondary: #64748b;
    --border-color: #e2e8f0;
    --shadow-sm: 0 1px 2px 0 rgb(0 0 0 / 0.05);
    --shadow-md: 0 4px 6px -1px rgb(0 0 0 / 0.1), 0 2px 4px -2px rgb(0 0 0 / 0.1);
    --shadow-lg: 0 10px 15px -3px rgb(0 0 0 / 0.1), 0 4px 6px -4px rgb(0 0 0 / 0.1);
    --radius-sm: 6px;
    --radius-md: 10px;
    --radius-lg: 16px;
    --transition: all 0.2s ease;
}

/* Reset & Base */
*, *::before, *::after {
    box-sizing: border-box;
    margin: 0;
    padding: 0;
}

html {
    font-size: 16px;
    scroll-behavior: smooth;
}

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen, Ubuntu, Cantarell, sans-serif;
    background: var(--background);
    color: var(--text-primary);
    line-height: 1.6;
    min-height: 100vh;
}

/* Container */
.container {
    max-width: 900px;
    margin: 0 auto;
    padding: 2rem 1.5rem;
    min-height: 100vh;
    display: flex;
    flex-direction: column;
}

/* Header */
header {
    text-align: center;
    margin-bottom: 2.5rem;
}

header h1 {
    font-size: 2.25rem;
    font-weight: 700;
    color: var(--text-primary);
    margin-bottom: 0.5rem;
}

.subtitle {
    color: var(--text-secondary);
    font-size: 1.125rem;
}

/* Main Content */
main {
    flex: 1;
    display: flex;
    flex-direction: column;
    gap: 2rem;
}

/* Upload Section */
.upload-section {
    width: 100%;
}

.upload-area {
    background: var(--surface);
    border: 2px dashed var(--border-color);
    border-radius: var(--radius-lg);
    padding: 3rem 2rem;
    text-align: center;
    cursor: pointer;
    transition: var(--transition);
}

.upload-area:hover,
.upload-area.dragover {
    border-color: var(--primary-color);
    background: #f0f0ff;
}

.upload-icon {
    color: var(--primary-color);
    margin-bottom: 1rem;
}

.upload-text {
    font-size: 1.25rem;
    font-weight: 600;
    color: var(--text-primary);
    margin-bottom: 0.5rem;
}

.upload-subtext {
    color: var(--text-secondary);
    font-size: 0.875rem;
}

.file-info {
    display: flex;
    align-items: center;
    justify-content: space-between;
    background: var(--surface);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-md);
    padding: 1rem 1.25rem;
    margin-top: 1rem;
    box-shadow: var(--shadow-sm);
}

.file-name {
    font-weight: 500;
    color: var(--text-primary);
    word-break: break-all;
}

.btn-clear {
    background: none;
    border: none;
    color: var(--text-secondary);
    cursor: pointer;
    padding: 0.25rem;
    border-radius: var(--radius-sm);
    transition: var(--transition);
    display: flex;
    align-items: center;
    justify-content: center;
}

.btn-clear:hover {
    color: var(--error-color);
    background: #fef2f2;
}

/* Options Section */
.options-section {
    background: var(--surface);
    border-radius: var(--radius-lg);
    padding: 1.75rem;
    box-shadow: var(--shadow-md);
}

.options-section h2 {
    font-size: 1.125rem;
    font-weight: 600;
    margin-bottom: 1.25rem;
    color: var(--text-primary);
}

.options-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 1.5rem;
    margin-bottom: 1.5rem;
}

.option-group {
    display: flex;
    flex-direction: column;
    gap: 0.5rem;
}

.option-group label {
    font-weight: 500;
    font-size: 0.875rem;
    color: var(--text-secondary);
}

.option-group select,
.option-group input {
    padding: 0.75rem 1rem;
    border: 1px solid var(--border-color);
    border-radius: var(--radius-sm);
    font-size: 1rem;
    background: var(--surface);
    color: var(--text-primary);
    transition: var(--transition);
}

.option-group select:focus,
.option-group input:focus {
    outline: none;
    border-color: var(--primary-color);
    box-shadow: 0 0 0 3px rgba(79, 70, 229, 0.1);
}

.page-range-inputs {
    display: flex;
    flex-direction: column;
    gap: 0.75rem;
}

.custom-range {
    display: flex;
    align-items: center;
    gap: 0.75rem;
}

.custom-range input {
    width: 80px;
    text-align: center;
}

.custom-range span {
    color: var(--text-secondary);
    font-size: 0.875rem;
}

.page-info {
    font-size: 0.75rem;
    color: var(--text-secondary);
}

/* Buttons */
.btn-primary {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: 0.5rem;
    background: var(--primary-color);
    color: white;
    border: none;
    border-radius: var(--radius-md);
    padding: 0.875rem 1.75rem;
    font-size: 1rem;
    font-weight: 600;
    cursor: pointer;
    transition: var(--transition);
    width: 100%;
}

.btn-primary:hover:not(:disabled) {
    background: var(--primary-hover);
    transform: translateY(-1px);
}

.btn-primary:disabled {
    opacity: 0.6;
    cursor: not-allowed;
}

.btn-secondary {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: 0.375rem;
    background: var(--surface);
    color: var(--text-primary);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-sm);
    padding: 0.625rem 1rem;
    font-size: 0.875rem;
    font-weight: 500;
    cursor: pointer;
    transition: var(--transition);
}

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

/* Progress Section */
.progress-section {
    background: var(--surface);
    border-radius: var(--radius-lg);
    padding: 2rem;
    box-shadow: var(--shadow-md);
    text-align: center;
}

.progress-bar {
    width: 100%;
    height: 8px;
    background: var(--border-color);
    border-radius: 4px;
    overflow: hidden;
    margin-bottom: 1rem;
}

.progress-fill {
    height: 100%;
    background: linear-gradient(90deg, var(--primary-color), #818cf8);
    border-radius: 4px;
    transition: width 0.3s ease;
    width: 0%;
}

.progress-text {
    color: var(--text-secondary);
    font-size: 0.875rem;
}

/* Results Section */
.results-section {
    background: var(--surface);
    border-radius: var(--radius-lg);
    padding: 1.75rem;
    box-shadow: var(--shadow-md);
}

.results-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    flex-wrap: wrap;
    gap: 1rem;
    margin-bottom: 1rem;
}

.results-header h2 {
    font-size: 1.125rem;
    font-weight: 600;
    color: var(--text-primary);
}

.results-actions {
    display: flex;
    gap: 0.75rem;
}

.results-stats {
    font-size: 0.875rem;
    color: var(--text-secondary);
    margin-bottom: 1rem;
    padding-bottom: 1rem;
    border-bottom: 1px solid var(--border-color);
}

.text-output-container {
    position: relative;
}

.text-output {
    width: 100%;
    min-height: 300px;
    max-height: 500px;
    padding: 1.25rem;
    border: 1px solid var(--border-color);
    border-radius: var(--radius-md);
    font-family: 'Monaco', 'Menlo', 'Ubuntu Mono', monospace;
    font-size: 0.875rem;
    line-height: 1.7;
    resize: vertical;
    background: #fafafa;
    color: var(--text-primary);
}

.text-output:focus {
    outline: none;
    border-color: var(--primary-color);
}

/* Footer */
footer {
    margin-top: 3rem;
    padding-top: 2rem;
    border-top: 1px solid var(--border-color);
    text-align: center;
}

footer p {
    color: var(--text-secondary);
    font-size: 0.875rem;
}

footer a {
    color: var(--primary-color);
    text-decoration: none;
    font-weight: 500;
    transition: var(--transition);
}

footer a:hover {
    text-decoration: underline;
}

/* Toast Notification */
.toast {
    position: fixed;
    bottom: 2rem;
    left: 50%;
    transform: translateX(-50%) translateY(100px);
    background: var(--text-primary);
    color: white;
    padding: 0.875rem 1.5rem;
    border-radius: var(--radius-md);
    font-size: 0.875rem;
    font-weight: 500;
    box-shadow: var(--shadow-lg);
    opacity: 0;
    transition: all 0.3s ease;
    z-index: 1000;
}

.toast.show {
    transform: translateX(-50%) translateY(0);
    opacity: 1;
}

.toast.success {
    background: var(--success-color);
}

.toast.error {
    background: var(--error-color);
}

/* Hidden utility */
[hidden] {
    display: none !important;
}

/* Mobile Responsiveness */
@media (max-width: 768px) {
    .container {
        padding: 1.5rem 1rem;
    }

    header h1 {
        font-size: 1.75rem;
    }

    .subtitle {
        font-size: 1rem;
    }

    .upload-area {
        padding: 2rem 1.5rem;
    }

    .upload-icon svg {
        width: 48px;
        height: 48px;
    }

    .upload-text {
        font-size: 1.125rem;
    }

    .options-section,
    .progress-section,
    .results-section {
        padding: 1.25rem;
    }

    .options-grid {
        grid-template-columns: 1fr;
    }

    .results-header {
        flex-direction: column;
        align-items: flex-start;
    }

    .results-actions {
        width: 100%;
    }

    .results-actions .btn-secondary {
        flex: 1;
    }

    .text-output {
        min-height: 200px;
        font-size: 0.8125rem;
    }

    .custom-range {
        flex-wrap: wrap;
    }

    .custom-range input {
        width: 70px;
    }
}

@media (max-width: 480px) {
    header h1 {
        font-size: 1.5rem;
    }

    .upload-area {
        padding: 1.5rem 1rem;
    }

    .btn-primary {
        padding: 0.75rem 1.25rem;
        font-size: 0.9375rem;
    }
}

/* Print styles */
@media print {
    .upload-section,
    .options-section,
    .progress-section,
    .results-header,
    footer {
        display: none;
    }

    .results-section {
        box-shadow: none;
        padding: 0;
    }

    .text-output {
        border: none;
        max-height: none;
        background: white;
    }
}