/* CSS Variables */
:root {
    --primary-color: #6366f1;
    --primary-hover: #4f46e5;
    --secondary-color: #8b5cf6;
    --success-color: #10b981;
    --error-color: #ef4444;
    --warning-color: #f59e0b;
    --background: #0f172a;
    --surface: #1e293b;
    --surface-hover: #334155;
    --border: #334155;
    --text-primary: #f1f5f9;
    --text-secondary: #94a3b8;
    --text-muted: #64748b;
    --code-bg: #0d1117;
    --shadow: 0 4px 6px -1px rgba(0, 0, 0, 0.3), 0 2px 4px -2px rgba(0, 0, 0, 0.2);
    --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.3), 0 4px 6px -4px rgba(0, 0, 0, 0.2);
    --radius: 12px;
    --radius-sm: 8px;
    --transition: all 0.2s ease;
}

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

/* Base */
html {
    font-size: 16px;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
}

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

/* 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: 2.5rem;
    font-weight: 700;
    background: linear-gradient(135deg, var(--primary-color), var(--secondary-color));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
    margin-bottom: 0.5rem;
}

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

/* Main Content */
main {
    flex: 1;
}

/* Tabs */
.tabs {
    display: flex;
    gap: 0.5rem;
    margin-bottom: 1.5rem;
    background: var(--surface);
    padding: 0.5rem;
    border-radius: var(--radius);
}

.tab-btn {
    flex: 1;
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 0.5rem;
    padding: 0.875rem 1.5rem;
    border: none;
    background: transparent;
    color: var(--text-secondary);
    font-size: 1rem;
    font-weight: 500;
    cursor: pointer;
    border-radius: var(--radius-sm);
    transition: var(--transition);
}

.tab-btn:hover {
    color: var(--text-primary);
    background: var(--surface-hover);
}

.tab-btn.active {
    background: var(--primary-color);
    color: white;
}

.tab-btn svg {
    flex-shrink: 0;
}

/* Tab Panels */
.tab-panel {
    display: none;
}

.tab-panel.active {
    display: block;
}

/* Upload Zone */
.upload-zone {
    border: 2px dashed var(--border);
    border-radius: var(--radius);
    padding: 3rem 2rem;
    text-align: center;
    cursor: pointer;
    transition: var(--transition);
    background: var(--surface);
}

.upload-zone:hover,
.upload-zone.dragover {
    border-color: var(--primary-color);
    background: rgba(99, 102, 241, 0.1);
}

.upload-zone svg {
    color: var(--text-muted);
    margin-bottom: 1rem;
}

.upload-zone p {
    color: var(--text-primary);
    font-size: 1.125rem;
    margin-bottom: 0.5rem;
}

.upload-zone .file-types {
    color: var(--text-muted);
    font-size: 0.875rem;
}

/* File Info */
.file-info {
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 1rem;
    padding: 1rem 1.25rem;
    background: var(--surface);
    border-radius: var(--radius);
    margin-top: 1rem;
}

.file-details {
    display: flex;
    flex-wrap: wrap;
    gap: 0.5rem 1.5rem;
}

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

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

.btn-clear {
    display: flex;
    align-items: center;
    justify-content: center;
    width: 36px;
    height: 36px;
    border: none;
    background: var(--surface-hover);
    color: var(--text-secondary);
    border-radius: var(--radius-sm);
    cursor: pointer;
    transition: var(--transition);
    flex-shrink: 0;
}

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

/* Output Section */
.output-section {
    margin-top: 1.5rem;
    background: var(--surface);
    border-radius: var(--radius);
    overflow: hidden;
}

.output-header {
    display: flex;
    align-items: center;
    justify-content: space-between;
    flex-wrap: wrap;
    gap: 1rem;
    padding: 1rem 1.25rem;
    border-bottom: 1px solid var(--border);
}

.output-header h3 {
    font-size: 1rem;
    font-weight: 600;
    color: var(--text-primary);
}

.output-actions {
    display: flex;
    gap: 0.5rem;
}

.btn-action {
    display: flex;
    align-items: center;
    gap: 0.375rem;
    padding: 0.5rem 0.875rem;
    border: 1px solid var(--border);
    background: transparent;
    color: var(--text-secondary);
    font-size: 0.875rem;
    font-weight: 500;
    border-radius: var(--radius-sm);
    cursor: pointer;
    transition: var(--transition);
}

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

/* Code Container */
.code-container {
    background: var(--code-bg);
    overflow-x: auto;
}

.code-container pre {
    margin: 0;
    padding: 1.25rem;
}

.code-container code {
    font-family: 'SF Mono', Monaco, 'Cascadia Code', 'Consolas', monospace;
    font-size: 0.8125rem;
    line-height: 1.7;
    color: var(--text-primary);
    word-break: break-all;
    white-space: pre-wrap;
}

/* Syntax Highlighting */
.code-container code .uri-scheme {
    color: #ff7b72;
}

.code-container code .uri-mime {
    color: #79c0ff;
}

.code-container code .uri-encoding {
    color: #a5d6ff;
}

.code-container code .uri-separator {
    color: #8b949e;
}

.code-container code .uri-data {
    color: #7ee787;
}

/* URI Stats */
.uri-stats {
    padding: 0.75rem 1.25rem;
    border-top: 1px solid var(--border);
    font-size: 0.8125rem;
    color: var(--text-muted);
}

/* Preview Section */
.preview-section {
    margin-top: 1.5rem;
    background: var(--surface);
    border-radius: var(--radius);
    padding: 1.25rem;
}

.preview-section h3 {
    font-size: 1rem;
    font-weight: 600;
    color: var(--text-primary);
    margin-bottom: 1rem;
}

.preview-container {
    background: var(--code-bg);
    border-radius: var(--radius-sm);
    padding: 1rem;
    display: flex;
    align-items: center;
    justify-content: center;
    min-height: 150px;
    overflow: hidden;
}

.preview-container img {
    max-width: 100%;
    max-height: 400px;
    object-fit: contain;
    border-radius: var(--radius-sm);
}

.preview-container video,
.preview-container audio {
    max-width: 100%;
    border-radius: var(--radius-sm);
}

.preview-container .preview-text {
    width: 100%;
    max-height: 300px;
    overflow: auto;
    font-family: 'SF Mono', Monaco, 'Cascadia Code', 'Consolas', monospace;
    font-size: 0.8125rem;
    color: var(--text-primary);
    white-space: pre-wrap;
    word-break: break-word;
}

.preview-container .preview-icon {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 0.75rem;
    color: var(--text-muted);
}

.preview-container .preview-icon svg {
    opacity: 0.5;
}

/* Input Section (Decode) */
.input-section {
    margin-bottom: 1.5rem;
}

.input-section label {
    display: block;
    font-size: 0.875rem;
    font-weight: 500;
    color: var(--text-secondary);
    margin-bottom: 0.5rem;
}

.input-section textarea {
    width: 100%;
    min-height: 200px;
    padding: 1rem;
    border: 1px solid var(--border);
    background: var(--surface);
    color: var(--text-primary);
    font-family: 'SF Mono', Monaco, 'Cascadia Code', 'Consolas', monospace;
    font-size: 0.8125rem;
    line-height: 1.6;
    border-radius: var(--radius);
    resize: vertical;
    transition: var(--transition);
}

.input-section textarea:focus {
    outline: none;
    border-color: var(--primary-color);
    box-shadow: 0 0 0 3px rgba(99, 102, 241, 0.2);
}

.input-section textarea::placeholder {
    color: var(--text-muted);
}

/* Primary Button */
.btn-primary {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 0.5rem;
    width: 100%;
    padding: 1rem 1.5rem;
    border: none;
    background: var(--primary-color);
    color: white;
    font-size: 1rem;
    font-weight: 600;
    border-radius: var(--radius);
    cursor: pointer;
    transition: var(--transition);
}

.btn-primary:hover {
    background: var(--primary-hover);
    transform: translateY(-1px);
    box-shadow: var(--shadow-lg);
}

.btn-primary:active {
    transform: translateY(0);
}

/* Decode Output */
.decode-output {
    margin-top: 1.5rem;
}

.decode-info {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(150px, 1fr));
    gap: 1rem;
    padding: 1.25rem;
    background: var(--surface);
    border-radius: var(--radius);
    margin-bottom: 1.5rem;
}

.info-item {
    display: flex;
    flex-direction: column;
    gap: 0.25rem;
}

.info-label {
    font-size: 0.75rem;
    font-weight: 500;
    color: var(--text-muted);
    text-transform: uppercase;
    letter-spacing: 0.05em;
}

.info-value {
    font-size: 0.9375rem;
    color: var(--text-primary);
    word-break: break-all;
}

.decode-output .preview-section {
    margin-top: 0;
    margin-bottom: 1.5rem;
}

/* Footer */
footer {
    margin-top: 3rem;
    padding-top: 1.5rem;
    border-top: 1px solid var(--border);
    text-align: center;
}

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

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

footer a:hover {
    color: var(--secondary-color);
    text-decoration: underline;
}

/* Toast Notification */
.toast {
    position: fixed;
    bottom: 2rem;
    left: 50%;
    transform: translateX(-50%) translateY(100px);
    padding: 0.875rem 1.5rem;
    background: var(--surface);
    color: var(--text-primary);
    border-radius: var(--radius);
    box-shadow: var(--shadow-lg);
    font-size: 0.9375rem;
    opacity: 0;
    transition: all 0.3s ease;
    z-index: 1000;
    pointer-events: none;
}

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

.toast.success {
    border-left: 4px solid var(--success-color);
}

.toast.error {
    border-left: 4px solid var(--error-color);
}

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

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

    header h1 {
        font-size: 2rem;
    }

    header .subtitle {
        font-size: 1rem;
    }

    .tabs {
        flex-direction: column;
    }

    .tab-btn {
        padding: 0.75rem 1rem;
    }

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

    .upload-zone svg {
        width: 40px;
        height: 40px;
    }

    .upload-zone p {
        font-size: 1rem;
    }

    .file-info {
        flex-direction: column;
        align-items: flex-start;
    }

    .btn-clear {
        align-self: flex-end;
    }

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

    .output-actions {
        width: 100%;
    }

    .btn-action {
        flex: 1;
        justify-content: center;
    }

    .decode-info {
        grid-template-columns: 1fr;
    }
}

@media (max-width: 480px) {
    header h1 {
        font-size: 1.75rem;
    }

    .code-container code {
        font-size: 0.75rem;
    }
}

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

.tab-panel.active {
    animation: fadeIn 0.3s ease;
}

/* Focus Styles */
button:focus-visible,
textarea:focus-visible {
    outline: 2px solid var(--primary-color);
    outline-offset: 2px;
}

/* Scrollbar Styles */
::-webkit-scrollbar {
    width: 8px;
    height: 8px;
}

::-webkit-scrollbar-track {
    background: var(--surface);
    border-radius: 4px;
}

::-webkit-scrollbar-thumb {
    background: var(--border);
    border-radius: 4px;
}

::-webkit-scrollbar-thumb:hover {
    background: var(--text-muted);
}