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

:root {
    --primary-color: #0052CC;
    --primary-hover: #0747A6;
    --success-color: #00875A;
    --error-color: #DE350B;
    --bg-color: #F4F5F7;
    --card-bg: #FFFFFF;
    --text-primary: #172B4D;
    --text-secondary: #6B778C;
    --border-color: #DFE1E6;
    --shadow-sm: 0 1px 2px rgba(0, 0, 0, 0.06);
    --shadow-md: 0 4px 6px rgba(0, 0, 0, 0.1);
    --shadow-lg: 0 10px 24px rgba(0, 0, 0, 0.1);
    --radius: 8px;
}

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', 'Helvetica Neue', Arial, sans-serif;
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    min-height: 100vh;
    color: var(--text-primary);
    line-height: 1.6;
}

.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 2rem;
}

header {
    text-align: center;
    margin-bottom: 3rem;
    color: white;
}

h1 {
    font-size: 2.5rem;
    font-weight: 700;
    margin-bottom: 0.5rem;
    text-shadow: 0 2px 4px rgba(0, 0, 0, 0.2);
}

.subtitle {
    font-size: 1.125rem;
    opacity: 0.95;
    margin-bottom: 1.5rem;
}

.lang-switcher {
    display: inline-flex;
    gap: 0.5rem;
    background: rgba(255, 255, 255, 0.2);
    padding: 0.25rem;
    border-radius: var(--radius);
    backdrop-filter: blur(10px);
}

.lang-btn {
    padding: 0.5rem 1rem;
    background: transparent;
    color: white;
    border: none;
    border-radius: 6px;
    cursor: pointer;
    font-size: 0.875rem;
    font-weight: 500;
    transition: all 0.2s;
}

.lang-btn:hover {
    background: rgba(255, 255, 255, 0.2);
}

.lang-btn.active {
    background: white;
    color: var(--primary-color);
}

.card {
    background: var(--card-bg);
    border-radius: var(--radius);
    padding: 2rem;
    box-shadow: var(--shadow-lg);
    margin-bottom: 2rem;
}

h2 {
    font-size: 1.5rem;
    font-weight: 600;
    margin-bottom: 1.5rem;
    color: var(--text-primary);
}

.current-time-display {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 1.5rem;
}

.time-item {
    padding: 1rem;
    background: var(--bg-color);
    border-radius: 6px;
    position: relative;
}

.time-label {
    font-size: 0.875rem;
    color: var(--text-secondary);
    margin-bottom: 0.5rem;
    font-weight: 500;
}

.time-value {
    font-size: 1.25rem;
    font-weight: 600;
    color: var(--text-primary);
    word-break: break-all;
}

.time-value.mono {
    font-family: 'Courier New', monospace;
}

.copy-btn {
    position: absolute;
    top: 1rem;
    right: 1rem;
    padding: 0.25rem 0.75rem;
    background: var(--primary-color);
    color: white;
    border: none;
    border-radius: 4px;
    font-size: 0.75rem;
    cursor: pointer;
    transition: all 0.2s;
}

.copy-btn:hover {
    background: var(--primary-hover);
    transform: translateY(-1px);
}

.copy-btn.copied {
    background: var(--success-color);
}

.input-group {
    display: flex;
    flex-direction: column;
    gap: 1rem;
}

.input-field {
    padding: 0.75rem 1rem;
    border: 2px solid var(--border-color);
    border-radius: 6px;
    font-size: 1rem;
    transition: all 0.2s;
    background: white;
}

.input-field:focus {
    outline: none;
    border-color: var(--primary-color);
    box-shadow: 0 0 0 3px rgba(0, 82, 204, 0.1);
}

.input-field.mono {
    font-family: 'Courier New', monospace;
}

.radio-group {
    display: flex;
    gap: 1.5rem;
}

.radio-label {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    cursor: pointer;
    font-size: 0.875rem;
}

.radio-label input[type="radio"] {
    width: 18px;
    height: 18px;
    accent-color: var(--primary-color);
}

.btn-primary {
    padding: 0.75rem 2rem;
    background: var(--primary-color);
    color: white;
    border: none;
    border-radius: 6px;
    font-size: 1rem;
    font-weight: 500;
    cursor: pointer;
    transition: all 0.2s;
}

.btn-primary:hover {
    background: var(--primary-hover);
    transform: translateY(-2px);
    box-shadow: var(--shadow-md);
}

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

.result-box {
    margin-top: 1.5rem;
    padding: 1.5rem;
    background: var(--bg-color);
    border-radius: 6px;
    min-height: 60px;
}

.result-item {
    display: flex;
    align-items: center;
    gap: 1rem;
    padding: 0.75rem 0;
    border-bottom: 1px solid var(--border-color);
}

.result-item:last-child {
    border-bottom: none;
}

.result-label {
    font-size: 0.875rem;
    color: var(--text-secondary);
    min-width: 120px;
    font-weight: 500;
}

.result-value {
    flex: 1;
    font-weight: 600;
    word-break: break-all;
}

.result-value.mono {
    font-family: 'Courier New', monospace;
}

.copy-btn-small {
    padding: 0.25rem 0.75rem;
    background: var(--primary-color);
    color: white;
    border: none;
    border-radius: 4px;
    font-size: 0.75rem;
    cursor: pointer;
    transition: all 0.2s;
}

.copy-btn-small:hover {
    background: var(--primary-hover);
}

.copy-btn-small.copied {
    background: var(--success-color);
}

.error {
    color: var(--error-color);
    padding: 0.75rem;
    background: rgba(222, 53, 11, 0.1);
    border-radius: 4px;
    font-size: 0.875rem;
}

.info-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: 1.5rem;
    margin-top: 1.5rem;
}

.info-item {
    padding: 1.25rem;
    background: var(--bg-color);
    border-radius: 6px;
    text-align: center;
}

.info-item h3 {
    font-size: 0.875rem;
    color: var(--text-secondary);
    margin-bottom: 0.5rem;
    font-weight: 500;
}

.info-item p {
    font-size: 0.875rem;
    color: var(--text-primary);
    margin-bottom: 0.5rem;
}

.info-item code {
    display: block;
    font-family: 'Courier New', monospace;
    font-size: 1.125rem;
    font-weight: 600;
    color: var(--primary-color);
    background: white;
    padding: 0.5rem;
    border-radius: 4px;
    margin-top: 0.5rem;
}

footer {
    text-align: center;
    padding: 2rem 0;
    color: white;
    opacity: 0.9;
}

@media (max-width: 768px) {
    .container {
        padding: 1rem;
    }
    
    h1 {
        font-size: 2rem;
    }
    
    .card {
        padding: 1.5rem;
    }
    
    .current-time-display {
        grid-template-columns: 1fr;
    }
    
    .info-grid {
        grid-template-columns: 1fr;
    }
    
    .time-item {
        position: relative;
        padding-bottom: 2.5rem;
    }
    
    .copy-btn {
        position: absolute;
        bottom: 0.5rem;
        right: 0.5rem;
        top: auto;
    }
}

@media (prefers-reduced-motion: reduce) {
    * {
        animation: none !important;
        transition: none !important;
    }
}