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

/* Screen reader only content */
.sr-only {
    position: absolute;
    width: 1px;
    height: 1px;
    padding: 0;
    margin: -1px;
    overflow: hidden;
    clip: rect(0, 0, 0, 0);
    white-space: nowrap;
    border: 0;
}

body {
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    line-height: 1.6;
    color: #333;
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    min-height: 100vh;
}

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

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

header h1 {
    font-size: 2.5rem;
    margin-bottom: 10px;
    text-shadow: 2px 2px 4px rgba(0,0,0,0.3);
}

header p {
    font-size: 1.1rem;
    opacity: 0.9;
}

/* Main Content */
main {
    background: white;
    border-radius: 15px;
    padding: 30px;
    box-shadow: 0 10px 30px rgba(0,0,0,0.2);
    margin-bottom: 20px;
}

/* Input Section */
.input-section {
    margin-bottom: 30px;
}

.input-section h2 {
    color: #4a5568;
    margin-bottom: 10px;
    font-size: 1.5rem;
}

.input-section p {
    color: #666;
    margin-bottom: 15px;
}

#dataInput {
    width: 100%;
    padding: 15px;
    border: 2px solid #e2e8f0;
    border-radius: 8px;
    font-family: 'Courier New', monospace;
    font-size: 14px;
    resize: vertical;
    transition: border-color 0.3s ease;
}

#dataInput:focus {
    outline: none;
    border-color: #667eea;
    box-shadow: 0 0 0 3px rgba(102, 126, 234, 0.1);
}

/* Settings Section */
.settings-section {
    margin-bottom: 30px;
    padding: 20px;
    background: #f7fafc;
    border-radius: 8px;
    border-left: 4px solid #667eea;
}

.settings-section h2 {
    color: #4a5568;
    margin-bottom: 15px;
    font-size: 1.5rem;
}

.input-group {
    margin-bottom: 20px;
}

.input-group label {
    display: block;
    margin-bottom: 8px;
    font-weight: 600;
    color: #4a5568;
}

#columnCount {
    width: 120px;
    padding: 10px;
    border: 2px solid #e2e8f0;
    border-radius: 6px;
    font-size: 16px;
    transition: border-color 0.3s ease;
}

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

/* Buttons */
.convert-btn, .clear-btn, .download-btn {
    padding: 12px 24px;
    border: none;
    border-radius: 6px;
    font-size: 16px;
    font-weight: 600;
    cursor: pointer;
    transition: all 0.3s ease;
    margin-right: 10px;
    margin-bottom: 10px;
}

.convert-btn {
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    color: white;
}

.convert-btn:hover {
    transform: translateY(-2px);
    box-shadow: 0 5px 15px rgba(102, 126, 234, 0.4);
}

.clear-btn {
    background: #e53e3e;
    color: white;
}

.clear-btn:hover {
    background: #c53030;
    transform: translateY(-2px);
}

.download-btn {
    background: #38a169;
    color: white;
}

.download-btn:hover {
    background: #2f855a;
    transform: translateY(-2px);
}

/* Results Section */
.results-section {
    margin-top: 30px;
    padding: 20px;
    background: #f7fafc;
    border-radius: 8px;
    border-left: 4px solid #38a169;
}

.results-section h2 {
    color: #4a5568;
    margin-bottom: 20px;
    font-size: 1.5rem;
}

.table-container {
    overflow-x: auto;
    margin-bottom: 20px;
    border-radius: 8px;
    box-shadow: 0 2px 10px rgba(0,0,0,0.1);
}

#resultTable {
    width: 100%;
    border-collapse: collapse;
    background: white;
    font-size: 14px;
}

#resultTable td {
    padding: 12px;
    text-align: left;
    border: 1px solid #e2e8f0;
}

#resultTable tr:nth-child(even) {
    background: #f8f9fa;
}

#resultTable tr:hover {
    background: #e6fffa;
}

/* Download Section */
.download-section {
    margin-top: 20px;
    padding-top: 20px;
    border-top: 2px solid #e2e8f0;
}

.download-section h3 {
    color: #4a5568;
    margin-bottom: 15px;
}

/* Footer */
footer {
    text-align: center;
    color: white;
    opacity: 0.8;
}

/* Ad Overlay */
.ad-overlay {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: rgba(0, 0, 0, 0.8);
    z-index: 1000;
    display: flex;
    justify-content: center;
    align-items: center;
}

.ad-content {
    background: white;
    border-radius: 15px;
    padding: 30px;
    max-width: 500px;
    width: 90%;
    text-align: center;
    box-shadow: 0 20px 40px rgba(0,0,0,0.3);
}

.ad-header {
    margin-bottom: 20px;
}

.ad-header h3 {
    color: #4a5568;
    margin-bottom: 10px;
}

.countdown {
    font-size: 2rem;
    font-weight: bold;
    color: #667eea;
    background: #f7fafc;
    border-radius: 50%;
    width: 60px;
    height: 60px;
    display: flex;
    align-items: center;
    justify-content: center;
    margin: 0 auto;
    border: 3px solid #667eea;
}

.ad-placeholder {
    background: #f7fafc;
    border: 2px dashed #cbd5e0;
    border-radius: 8px;
    padding: 40px 20px;
    margin: 20px 0;
    color: #666;
}

.loading-spinner {
    width: 40px;
    height: 40px;
    border: 4px solid #e2e8f0;
    border-top: 4px solid #667eea;
    border-radius: 50%;
    animation: spin 1s linear infinite;
    margin: 20px auto;
}

@keyframes spin {
    0% { transform: rotate(0deg); }
    100% { transform: rotate(360deg); }
}

.ad-footer {
    color: #666;
    font-size: 14px;
}

/* Responsive Design */
@media (max-width: 768px) {
    .container {
        padding: 10px;
    }
    
    header h1 {
        font-size: 2rem;
    }
    
    main {
        padding: 20px;
    }
    
    .convert-btn, .clear-btn, .download-btn {
        width: 100%;
        margin-right: 0;
        margin-bottom: 10px;
    }
    
    .ad-content {
        margin: 20px;
        padding: 20px;
    }
}