/* Reset and Base Styles */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen, Ubuntu, Cantarell, sans-serif;
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    min-height: 100vh;
    padding: 20px;
    color: #333;
}

.container {
    max-width: 900px;
    margin: 0 auto;
}

/* Header */
header {
    text-align: center;
    color: white;
    margin-bottom: 40px;
}

header h1 {
    font-size: 2.5rem;
    margin-bottom: 10px;
    text-shadow: 2px 2px 4px rgba(0, 0, 0, 0.2);
}

.subtitle {
    font-size: 1.1rem;
    opacity: 0.9;
}

/* Main Content */
main {
    background: white;
    border-radius: 16px;
    padding: 40px;
    box-shadow: 0 20px 60px rgba(0, 0, 0, 0.3);
}

/* Tabs */
.input-method-tabs {
    display: flex;
    gap: 10px;
    margin-bottom: 30px;
    border-bottom: 2px solid #e0e0e0;
}

.tab-btn {
    padding: 12px 24px;
    background: none;
    border: none;
    cursor: pointer;
    font-size: 1rem;
    font-weight: 500;
    color: #666;
    transition: all 0.3s ease;
    border-bottom: 3px solid transparent;
    margin-bottom: -2px;
}

.tab-btn.active {
    color: #667eea;
    border-bottom-color: #667eea;
}

.tab-btn:hover {
    color: #667eea;
}

/* Tab Content */
.tab-content {
    display: none;
}

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

/* Upload Area */
.upload-area {
    border: 3px dashed #d0d0d0;
    border-radius: 12px;
    padding: 60px 20px;
    text-align: center;
    transition: all 0.3s ease;
    cursor: pointer;
}

.upload-area:hover,
.upload-area.drag-over {
    border-color: #667eea;
    background-color: #f8f9ff;
}

.upload-icon {
    width: 80px;
    height: 80px;
    color: #667eea;
    margin-bottom: 20px;
}

.upload-text {
    font-size: 1.1rem;
    color: #666;
    margin-bottom: 20px;
}

.browse-btn {
    background: #667eea;
    color: white;
    border: none;
    padding: 12px 32px;
    font-size: 1rem;
    border-radius: 8px;
    cursor: pointer;
    transition: all 0.3s ease;
    font-weight: 500;
}

.browse-btn:hover {
    background: #5568d3;
    transform: translateY(-2px);
    box-shadow: 0 4px 12px rgba(102, 126, 234, 0.4);
}

/* Paste Area */
#jsonInput {
    width: 100%;
    min-height: 300px;
    padding: 20px;
    border: 2px solid #e0e0e0;
    border-radius: 8px;
    font-family: 'Courier New', monospace;
    font-size: 0.9rem;
    resize: vertical;
    transition: border-color 0.3s ease;
}

#jsonInput:focus {
    outline: none;
    border-color: #667eea;
}

.convert-btn {
    margin-top: 20px;
    background: #667eea;
    color: white;
    border: none;
    padding: 14px 40px;
    font-size: 1.1rem;
    border-radius: 8px;
    cursor: pointer;
    transition: all 0.3s ease;
    font-weight: 500;
    width: 100%;
}

.convert-btn:hover {
    background: #5568d3;
    transform: translateY(-2px);
    box-shadow: 0 4px 12px rgba(102, 126, 234, 0.4);
}

.convert-btn:disabled {
    background: #ccc;
    cursor: not-allowed;
    transform: none;
}

/* Status Messages */
.status-message {
    margin-top: 20px;
    padding: 16px;
    border-radius: 8px;
    font-weight: 500;
    text-align: center;
    transition: all 0.3s ease;
}

.status-message.hidden {
    display: none;
}

.status-message.success {
    background-color: #d4edda;
    color: #155724;
    border: 1px solid #c3e6cb;
}

.status-message.error {
    background-color: #f8d7da;
    color: #721c24;
    border: 1px solid #f5c6cb;
}

.status-message.info {
    background-color: #d1ecf1;
    color: #0c5460;
    border: 1px solid #bee5eb;
}

/* Preview Section */
.preview-section {
    margin-top: 30px;
    padding: 20px;
    background: #f8f9fa;
    border-radius: 8px;
}

.preview-section.hidden {
    display: none;
}

.preview-section h3 {
    margin-bottom: 15px;
    color: #333;
}

#previewContent {
    overflow-x: auto;
}

/* Features */
.features {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 30px;
    margin-top: 50px;
    padding-top: 40px;
    border-top: 2px solid #e0e0e0;
}

.feature {
    text-align: center;
}

.feature-icon {
    font-size: 3rem;
    display: block;
    margin-bottom: 15px;
}

.feature h3 {
    font-size: 1.2rem;
    margin-bottom: 10px;
    color: #333;
}

.feature p {
    color: #666;
    line-height: 1.6;
}

/* Footer */
footer {
    text-align: center;
    color: white;
    margin-top: 40px;
    padding: 20px;
    opacity: 0.9;
}

/* Responsive */
@media (max-width: 768px) {
    header h1 {
        font-size: 2rem;
    }

    main {
        padding: 25px;
    }

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

/* Loading Spinner */
@keyframes spin {
    to { transform: rotate(360deg); }
}

.loading {
    display: inline-block;
    width: 20px;
    height: 20px;
    border: 3px solid rgba(255, 255, 255, 0.3);
    border-radius: 50%;
    border-top-color: white;
    animation: spin 0.8s linear infinite;
    margin-left: 10px;
    vertical-align: middle;
}