* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
    background: #f0f2f5;
    color: #1a1a2e;
    line-height: 1.6;
}

.container {
    max-width: 800px;
    margin: 0 auto;
    padding: 0 20px;
}

header {
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    color: white;
    padding: 40px 0 30px;
    text-align: center;
}

header h1 {
    font-size: 2rem;
    margin-bottom: 8px;
}

header .subtitle {
    opacity: 0.9;
    font-size: 1rem;
}

.tool-card {
    background: white;
    border-radius: 16px;
    box-shadow: 0 4px 24px rgba(0,0,0,0.08);
    margin-top: -30px;
    position: relative;
    z-index: 10;
    overflow: hidden;
}

.input-section {
    padding: 30px;
    border-bottom: 1px solid #eee;
}

.input-section label {
    display: block;
    font-weight: 600;
    margin-bottom: 8px;
    color: #333;
}

.input-section textarea {
    width: 100%;
    min-height: 120px;
    padding: 14px;
    border: 2px solid #e0e0e0;
    border-radius: 10px;
    font-size: 15px;
    resize: vertical;
    transition: border-color 0.3s;
    font-family: inherit;
}

.input-section textarea:focus {
    outline: none;
    border-color: #667eea;
}

.options-row {
    display: flex;
    gap: 16px;
    margin-top: 16px;
}

.option-group {
    flex: 1;
}

.option-group label {
    display: block;
    font-size: 13px;
    color: #666;
    margin-bottom: 4px;
}

.option-group select {
    width: 100%;
    padding: 10px 12px;
    border: 2px solid #e0e0e0;
    border-radius: 8px;
    font-size: 14px;
    background: white;
    cursor: pointer;
}

#generateBtn {
    width: 100%;
    margin-top: 18px;
    padding: 14px;
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    color: white;
    border: none;
    border-radius: 10px;
    font-size: 16px;
    font-weight: 600;
    cursor: pointer;
    transition: transform 0.2s, opacity 0.3s;
}

#generateBtn:hover:not(:disabled) {
    transform: translateY(-1px);
    opacity: 0.95;
}

#generateBtn:disabled {
    opacity: 0.7;
    cursor: not-allowed;
}

.output-section {
    padding: 24px 30px;
}

.output-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 12px;
}

.output-header span {
    font-weight: 600;
    color: #333;
}

#copyBtn {
    padding: 6px 14px;
    background: #f0f0f0;
    border: none;
    border-radius: 6px;
    cursor: pointer;
    font-size: 13px;
    transition: background 0.2s;
}

#copyBtn:hover {
    background: #e0e0e0;
}

.result-box {
    min-height: 200px;
    padding: 16px;
    background: #fafafa;
    border: 2px solid #e0e0e0;
    border-radius: 10px;
    font-size: 15px;
    line-height: 1.8;
    white-space: pre-wrap;
    word-wrap: break-word;
}

.result-box .placeholder-text {
    color: #aaa;
    text-align: center;
    padding: 60px 0;
}

.features {
    margin-top: 40px;
    text-align: center;
}

.features h2 {
    font-size: 1.5rem;
    margin-bottom: 24px;
    color: #333;
}

.feature-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(160px, 1fr));
    gap: 20px;
}

.feature-item {
    padding: 20px;
    background: white;
    border-radius: 12px;
    box-shadow: 0 2px 12px rgba(0,0,0,0.05);
}

.feature-icon {
    font-size: 2rem;
    margin-bottom: 8px;
}

.feature-item h3 {
    font-size: 1rem;
    margin-bottom: 6px;
    color: #333;
}

.feature-item p {
    font-size: 13px;
    color: #666;
}

.seo-content {
    margin-top: 40px;
    padding: 30px;
    background: white;
    border-radius: 12px;
}

.seo-content h2 {
    font-size: 1.3rem;
    margin-bottom: 16px;
    color: #333;
}

.seo-content h3 {
    font-size: 1.1rem;
    margin-top: 20px;
    margin-bottom: 10px;
    color: #444;
}

.seo-content p {
    margin-bottom: 12px;
    color: #555;
}

.seo-content ol,
.seo-content ul {
    margin-left: 20px;
    margin-bottom: 16px;
    color: #555;
}

.seo-content li {
    margin-bottom: 6px;
}

footer {
    text-align: center;
    padding: 30px 0;
    margin-top: 40px;
    color: #888;
    font-size: 13px;
    border-top: 1px solid #e0e0e0;
}

@media (max-width: 600px) {
    header h1 { font-size: 1.5rem; }
    .options-row { flex-direction: column; }
    .input-section { padding: 20px; }
    .output-section { padding: 16px 20px; }
}