:root {
    --primary-color: #0052CC;
    --primary-hover: #0747A6;
    --secondary-color: #6B778C;
    --success-color: #36B37E;
    --danger-color: #DE350B;
    --warning-color: #FFAB00;
    --background-color: #FAFBFC;
    --surface-color: #FFFFFF;
    --text-primary: #172B4D;
    --text-secondary: #6B778C;
    --border-color: #DFE1E6;
    --shadow-sm: 0 1px 2px rgba(23, 43, 77, 0.08);
    --shadow-md: 0 4px 8px -2px rgba(23, 43, 77, 0.12);
    --shadow-lg: 0 8px 16px -4px rgba(23, 43, 77, 0.12);
    --radius-sm: 3px;
    --radius-md: 4px;
    --radius-lg: 8px;
    --font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', 'Roboto', 'Helvetica', 'Arial', sans-serif;
}

* {
    box-sizing: border-box;
}

body {
    margin: 0;
    padding: 0;
    font-family: var(--font-family);
    background-color: var(--background-color);
    color: var(--text-primary);
    line-height: 1.5;
}

.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 24px;
}

header {
    background-color: var(--surface-color);
    border-bottom: 1px solid var(--border-color);
    padding: 24px 0;
    box-shadow: var(--shadow-sm);
    position: relative;
}

h1 {
    margin: 0;
    font-size: 32px;
    font-weight: 600;
    color: var(--text-primary);
}

.subtitle {
    margin: 8px 0 0;
    font-size: 16px;
    color: var(--text-secondary);
}

.language-selector {
    position: absolute;
    top: 24px;
    right: 24px;
}

.language-selector select {
    padding: 8px 12px;
    border: 1px solid var(--border-color);
    border-radius: var(--radius-md);
    background-color: var(--surface-color);
    font-size: 14px;
    color: var(--text-primary);
    cursor: pointer;
}

main {
    padding: 32px 0;
}

.input-section {
    background-color: var(--surface-color);
    border-radius: var(--radius-lg);
    padding: 24px;
    margin-bottom: 24px;
    box-shadow: var(--shadow-md);
}

.pattern-input-container,
.test-string-container {
    margin-bottom: 20px;
}

label {
    display: block;
    margin-bottom: 8px;
    font-weight: 500;
    color: var(--text-primary);
}

.input-with-flags {
    display: flex;
    gap: 12px;
    align-items: center;
}

input[type="text"] {
    flex: 1;
    padding: 12px;
    border: 2px solid var(--border-color);
    border-radius: var(--radius-md);
    font-size: 16px;
    font-family: 'Consolas', 'Monaco', monospace;
    transition: border-color 0.2s;
}

input[type="text"]:focus {
    outline: none;
    border-color: var(--primary-color);
}

.flags-container {
    display: flex;
    gap: 12px;
    flex-wrap: wrap;
}

.flags-container label {
    display: flex;
    align-items: center;
    gap: 4px;
    margin: 0;
    font-size: 14px;
    font-weight: normal;
    cursor: pointer;
}

textarea {
    width: 100%;
    padding: 12px;
    border: 2px solid var(--border-color);
    border-radius: var(--radius-md);
    font-size: 16px;
    font-family: 'Consolas', 'Monaco', monospace;
    resize: vertical;
    transition: border-color 0.2s;
}

textarea:focus {
    outline: none;
    border-color: var(--primary-color);
}

.results-section {
    background-color: var(--surface-color);
    border-radius: var(--radius-lg);
    padding: 24px;
    box-shadow: var(--shadow-md);
}

.tabs {
    display: flex;
    gap: 4px;
    margin-bottom: 24px;
    border-bottom: 2px solid var(--border-color);
}

.tab-button {
    padding: 12px 20px;
    background: none;
    border: none;
    font-size: 16px;
    font-weight: 500;
    color: var(--text-secondary);
    cursor: pointer;
    position: relative;
    transition: color 0.2s;
}

.tab-button:hover {
    color: var(--text-primary);
}

.tab-button.active {
    color: var(--primary-color);
}

.tab-button.active::after {
    content: '';
    position: absolute;
    bottom: -2px;
    left: 0;
    right: 0;
    height: 2px;
    background-color: var(--primary-color);
}

.tab-content {
    min-height: 300px;
}

.tab-pane {
    display: none;
}

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

.match-count {
    font-size: 18px;
    font-weight: 500;
    color: var(--success-color);
    margin-bottom: 16px;
}

.no-matches {
    font-size: 16px;
    color: var(--text-secondary);
    text-align: center;
    padding: 40px;
}

.highlighted-text {
    background-color: var(--background-color);
    padding: 16px;
    border-radius: var(--radius-md);
    font-family: 'Consolas', 'Monaco', monospace;
    line-height: 1.6;
    white-space: pre-wrap;
    word-break: break-all;
    margin-bottom: 16px;
}

.match-highlight {
    background-color: #FFEB3B;
    padding: 2px 4px;
    border-radius: var(--radius-sm);
    font-weight: 600;
}

.match-details {
    border-top: 1px solid var(--border-color);
    padding-top: 16px;
}

.match-item {
    margin-bottom: 16px;
    padding: 12px;
    background-color: var(--background-color);
    border-radius: var(--radius-md);
}

.match-header {
    font-weight: 500;
    margin-bottom: 8px;
}

.match-groups {
    margin-left: 20px;
    font-size: 14px;
    color: var(--text-secondary);
}

.match-group {
    margin-bottom: 4px;
}

.error {
    color: var(--danger-color);
    padding: 12px;
    background-color: #FFEBE6;
    border-radius: var(--radius-md);
}

.pattern-part {
    background-color: var(--background-color);
    padding: 2px 6px;
    border-radius: var(--radius-sm);
    font-family: 'Consolas', 'Monaco', monospace;
    font-weight: 600;
    color: var(--primary-color);
}

.test-cases-controls {
    display: flex;
    gap: 12px;
    margin-bottom: 20px;
}

.test-case-item {
    display: grid;
    grid-template-columns: 1fr 150px 100px 100px;
    gap: 12px;
    align-items: center;
    margin-bottom: 12px;
    padding: 12px;
    background-color: var(--background-color);
    border-radius: var(--radius-md);
}

.test-case-string {
    padding: 8px 12px;
    border: 1px solid var(--border-color);
    border-radius: var(--radius-md);
    font-family: 'Consolas', 'Monaco', monospace;
}

.test-case-type {
    padding: 8px 12px;
    border: 1px solid var(--border-color);
    border-radius: var(--radius-md);
    background-color: var(--surface-color);
}

.test-case-result {
    text-align: center;
    font-weight: 500;
}

.test-pass {
    color: var(--success-color);
}

.test-fail {
    color: var(--danger-color);
}

.pattern-categories {
    display: flex;
    gap: 8px;
    margin-bottom: 20px;
    flex-wrap: wrap;
}

.category-button {
    padding: 8px 16px;
    background-color: var(--background-color);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-md);
    font-size: 14px;
    cursor: pointer;
    transition: all 0.2s;
}

.category-button:hover {
    background-color: var(--border-color);
}

.category-button.active {
    background-color: var(--primary-color);
    color: white;
    border-color: var(--primary-color);
}

.pattern-item {
    padding: 16px;
    margin-bottom: 12px;
    background-color: var(--background-color);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-md);
    cursor: pointer;
    transition: all 0.2s;
}

.pattern-item:hover {
    border-color: var(--primary-color);
    box-shadow: var(--shadow-md);
}

.pattern-name {
    font-weight: 500;
    margin-bottom: 4px;
}

.pattern-code {
    font-family: 'Consolas', 'Monaco', monospace;
    color: var(--primary-color);
    margin-bottom: 4px;
}

.pattern-description {
    font-size: 14px;
    color: var(--text-secondary);
}

.tools-section {
    margin-top: 24px;
    display: flex;
    gap: 12px;
    justify-content: center;
}

.button {
    padding: 12px 24px;
    border: none;
    border-radius: var(--radius-md);
    font-size: 16px;
    font-weight: 500;
    cursor: pointer;
    transition: all 0.2s;
}

.button-primary {
    background-color: var(--primary-color);
    color: white;
}

.button-primary:hover {
    background-color: var(--primary-hover);
}

.button-secondary {
    background-color: var(--background-color);
    color: var(--text-primary);
    border: 1px solid var(--border-color);
}

.button-secondary:hover {
    background-color: var(--border-color);
}

.button-danger {
    background-color: var(--danger-color);
    color: white;
    padding: 6px 12px;
    font-size: 14px;
}

.button-danger:hover {
    background-color: #BF2600;
}

footer {
    margin-top: 48px;
    padding: 24px 0;
    border-top: 1px solid var(--border-color);
    text-align: center;
    color: var(--text-secondary);
}

@media (max-width: 768px) {
    .container {
        padding: 0 16px;
    }
    
    h1 {
        font-size: 24px;
    }
    
    .language-selector {
        position: static;
        margin-top: 16px;
    }
    
    .input-with-flags {
        flex-direction: column;
        align-items: stretch;
    }
    
    .tabs {
        overflow-x: auto;
        -webkit-overflow-scrolling: touch;
    }
    
    .tab-button {
        white-space: nowrap;
    }
    
    .test-case-item {
        grid-template-columns: 1fr;
        gap: 8px;
    }
    
    .tools-section {
        flex-direction: column;
    }
    
    .pattern-categories {
        justify-content: center;
    }
}