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

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

.container {
    max-width: 1200px;
    margin: 0 auto;
    background: white;
    border-radius: 12px;
    box-shadow: 0 10px 40px rgba(0, 0, 0, 0.1);
    padding: 40px;
}

header {
    text-align: center;
    margin-bottom: 40px;
    padding-bottom: 20px;
    border-bottom: 2px solid #f0f0f0;
}

header h1 {
    font-size: 2.5em;
    color: #667eea;
    margin-bottom: 10px;
}

.subtitle {
    color: #666;
    font-size: 1.1em;
}

.form-section {
    background: #f8f9fa;
    padding: 30px;
    border-radius: 8px;
    margin-bottom: 30px;
}

.form-section h2 {
    margin-bottom: 20px;
    color: #333;
}

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

.form-row {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 20px;
}

label {
    display: block;
    margin-bottom: 8px;
    font-weight: 600;
    color: #555;
}

input[type="text"],
input[type="date"],
select {
    width: 100%;
    padding: 12px;
    border: 2px solid #e0e0e0;
    border-radius: 6px;
    font-size: 16px;
    transition: border-color 0.3s;
}

input[type="text"]:focus,
input[type="date"]:focus,
select:focus {
    outline: none;
    border-color: #667eea;
}

.btn-primary {
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    color: white;
    padding: 14px 30px;
    border: none;
    border-radius: 6px;
    font-size: 16px;
    font-weight: 600;
    cursor: pointer;
    transition: transform 0.2s, box-shadow 0.2s;
    width: 100%;
    margin-top: 10px;
}

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

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

.loading {
    text-align: center;
    padding: 40px;
}

.spinner {
    border: 4px solid #f3f3f3;
    border-top: 4px solid #667eea;
    border-radius: 50%;
    width: 50px;
    height: 50px;
    animation: spin 1s linear infinite;
    margin: 0 auto 20px;
}

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

.error {
    background: #fee;
    color: #c33;
    padding: 15px;
    border-radius: 6px;
    border-left: 4px solid #c33;
    margin-bottom: 20px;
}

.results-header {
    margin-bottom: 30px;
}

.results-header h2 {
    color: #333;
    margin-bottom: 10px;
}

.period-info {
    color: #666;
    font-size: 0.95em;
}

.stats-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: 20px;
    margin-bottom: 40px;
}

.stat-card {
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    color: white;
    padding: 25px;
    border-radius: 8px;
    text-align: center;
    box-shadow: 0 4px 15px rgba(102, 126, 234, 0.3);
}

.stat-value {
    font-size: 2.5em;
    font-weight: bold;
    margin-bottom: 8px;
}

.stat-label {
    font-size: 0.9em;
    opacity: 0.9;
}

.categories-section,
.top-commits-section {
    margin-top: 40px;
}

.categories-section h3,
.top-commits-section h3 {
    margin-bottom: 20px;
    color: #333;
}

.category-card {
    background: #f8f9fa;
    padding: 20px;
    border-radius: 8px;
    margin-bottom: 15px;
    border-left: 4px solid #667eea;
}

.category-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 10px;
}

.category-name {
    font-weight: 600;
    font-size: 1.1em;
    color: #333;
}

.category-count {
    background: #667eea;
    color: white;
    padding: 4px 12px;
    border-radius: 12px;
    font-size: 0.9em;
}

.category-description {
    color: #666;
    margin-bottom: 10px;
    font-size: 0.95em;
}

.key-changes {
    margin-top: 10px;
}

.key-changes-title {
    font-weight: 600;
    margin-bottom: 8px;
    color: #555;
    font-size: 0.9em;
}

.key-change-item {
    background: white;
    padding: 8px 12px;
    margin-bottom: 5px;
    border-radius: 4px;
    font-size: 0.9em;
    color: #444;
}

.commit-item {
    background: #f8f9fa;
    padding: 15px;
    border-radius: 6px;
    margin-bottom: 10px;
    border-left: 3px solid #667eea;
}

.commit-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 8px;
}

.commit-message {
    font-weight: 600;
    color: #333;
}

.commit-sha {
    font-family: monospace;
    font-size: 0.85em;
    color: #666;
    background: white;
    padding: 2px 6px;
    border-radius: 3px;
}

.commit-meta {
    display: flex;
    gap: 15px;
    font-size: 0.9em;
    color: #666;
    flex-wrap: wrap;
}

.commit-author {
    font-weight: 500;
}

.commit-author-info {
    color: #888;
    font-size: 0.9em;
    font-style: italic;
}

.commit-date {
    color: #888;
}

.commit-stats {
    display: flex;
    gap: 10px;
    margin-top: 8px;
}

.stat-badge {
    padding: 4px 8px;
    border-radius: 4px;
    font-size: 0.85em;
    font-weight: 500;
}

.stat-badge.files {
    background: #e3f2fd;
    color: #1976d2;
}

.stat-badge.additions {
    background: #e8f5e9;
    color: #388e3c;
}

.stat-badge.deletions {
    background: #ffebee;
    color: #d32f2f;
}

.tabs {
    display: flex;
    gap: 10px;
    margin-bottom: 20px;
    border-bottom: 2px solid #e0e0e0;
}

.tab-button {
    padding: 12px 20px;
    border: none;
    background: transparent;
    color: #666;
    font-size: 16px;
    font-weight: 600;
    cursor: pointer;
    border-bottom: 3px solid transparent;
    transition: all 0.3s;
}

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

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

.tab-content {
    display: none;
}

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

.ai-summary-box {
    background: linear-gradient(135deg, #f0f4ff 0%, #f5f0ff 100%);
    border: 2px solid #667eea;
    border-radius: 8px;
    padding: 25px;
    margin-bottom: 30px;
}

.ai-summary-box h3 {
    color: #667eea;
    margin-bottom: 15px;
    font-size: 1.3em;
}

.ai-summary-text {
    background: white;
    padding: 20px;
    border-radius: 6px;
    line-height: 1.8;
    color: #333;
    font-size: 1em;
}

.commits-count {
    margin-top: 15px;
    text-align: right;
    color: #666;
    font-size: 0.95em;
}

@media (max-width: 768px) {
    .container {
        padding: 20px;
    }

    header h1 {
        font-size: 2em;
    }

    .form-row {
        grid-template-columns: 1fr;
    }

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

    .tabs {
        flex-direction: column;
    }

    .tab-button {
        border-bottom: 2px solid #e0e0e0;
    }

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