* { 
    box-sizing: border-box; 
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif; 
}

body { 
    background-color: #f4f7f6; 
    display: flex; 
    justify-content: center; 
    align-items: center; 
    height: 100vh; 
    margin: 0; 
}

.container { 
    background: white; 
    padding: 2rem; 
    border-radius: 16px; 
    box-shadow: 0 4px 15px rgba(0,0,0,0.05); 
    text-align: center; 
    width: 90%; 
    max-width: 400px; 
}

h1 { 
    color: #2c3e50; 
    margin-top: 0;
    margin-bottom: 8px; 
}

p { 
    color: #7f8c8d; 
    font-size: 0.95rem; 
    margin-bottom: 24px; 
}

input { 
    width: 100%; 
    padding: 15px; 
    margin-bottom: 20px; 
    border: 1px solid #dcdde1; 
    border-radius: 8px; 
    font-size: 1.1rem; 
    text-align: center;
    transition: border-color 0.3s;
}

input:focus {
    outline: none;
    border-color: #3498db;
}

.button-group { 
    display: flex; 
    gap: 12px; 
}

.btn { 
    flex: 1; 
    padding: 16px; 
    border: none; 
    border-radius: 8px; 
    font-size: 1.2rem; 
    font-weight: bold; 
    cursor: pointer; 
    color: white; 
}

.btn:active { 
    transform: scale(0.98); 
}

.btn-in { 
    background-color: #2ecc71; /* 출근 - 초록색 */
}

.btn-out { 
    background-color: #e74c3c; /* 퇴근 - 빨간색 */
}

.message { 
    margin-top: 15px; 
    font-size: 0.95rem; 
    min-height: 20px;
    font-weight: bold;
}