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

body {
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    min-height: 100vh;
    display: flex;
    align-items: center;
    justify-content: center;
    padding: 20px;
}

.container {
    background: white;
    border-radius: 20px;
    padding: 40px;
    box-shadow: 0 20px 40px rgba(0, 0, 0, 0.1);
    max-width: 500px;
    width: 100%;
    position: relative;
}

.lang-select {
    position: absolute;
    top: 20px;
    right: 20px;
    display: flex;
    align-items: center;
    gap: 8px;
}

.lang-select select {
    padding: 5px 10px;
    border: 1px solid #ddd;
    border-radius: 8px;
    background: white;
    font-size: 14px;
    cursor: pointer;
}

h1 {
    text-align: center;
    color: #333;
    margin-bottom: 30px;
    font-size: 2.5em;
    font-weight: 700;
}

.password-box {
    display: flex;
    gap: 10px;
    margin-bottom: 30px;
    position: relative;
}

#password {
    flex: 1;
    padding: 15px 20px;
    border: 2px solid #e1e5e9;
    border-radius: 12px;
    font-size: 18px;
    font-family: 'Courier New', monospace;
    background: #f8f9fa;
    color: #333;
    transition: all 0.3s ease;
}

#password:focus {
    outline: none;
    border-color: #667eea;
    background: white;
    box-shadow: 0 0 0 3px rgba(102, 126, 234, 0.1);
}

.copy-btn {
    padding: 15px 20px;
    background: #667eea;
    color: white;
    border: none;
    border-radius: 12px;
    cursor: pointer;
    font-size: 18px;
    transition: all 0.3s ease;
    min-width: 60px;
}

.copy-btn:hover {
    background: #5a6fd8;
    transform: translateY(-2px);
    box-shadow: 0 5px 15px rgba(102, 126, 234, 0.3);
}

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

.options {
    margin-bottom: 30px;
}

.option {
    margin-bottom: 20px;
    display: flex;
    align-items: center;
    gap: 15px;
}

.option label {
    display: flex;
    align-items: center;
    gap: 10px;
    cursor: pointer;
    font-size: 16px;
    color: #555;
    flex: 1;
}

.option input[type="checkbox"] {
    width: 20px;
    height: 20px;
    accent-color: #667eea;
    cursor: pointer;
}

.option input[type="range"] {
    flex: 1;
    height: 6px;
    border-radius: 3px;
    background: #e1e5e9;
    outline: none;
    cursor: pointer;
    -webkit-appearance: none;
}

.option input[type="range"]::-webkit-slider-thumb {
    -webkit-appearance: none;
    appearance: none;
    width: 20px;
    height: 20px;
    border-radius: 50%;
    background: #667eea;
    cursor: pointer;
    box-shadow: 0 2px 6px rgba(0, 0, 0, 0.2);
}

.option input[type="range"]::-moz-range-thumb {
    width: 20px;
    height: 20px;
    border-radius: 50%;
    background: #667eea;
    cursor: pointer;
    border: none;
    box-shadow: 0 2px 6px rgba(0, 0, 0, 0.2);
}

#lengthValue {
    font-weight: 600;
    color: #667eea;
    min-width: 30px;
    text-align: center;
}

.label-text {
    font-weight: 500;
}

.generate-btn {
    width: 100%;
    padding: 18px;
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    color: white;
    border: none;
    border-radius: 12px;
    font-size: 18px;
    font-weight: 600;
    cursor: pointer;
    transition: all 0.3s ease;
    margin-bottom: 25px;
}

.generate-btn:hover {
    transform: translateY(-3px);
    box-shadow: 0 10px 25px rgba(102, 126, 234, 0.3);
}

.generate-btn:active {
    transform: translateY(-1px);
}

.strength-meter {
    display: flex;
    align-items: center;
    gap: 15px;
    padding: 20px;
    background: #f8f9fa;
    border-radius: 12px;
    border: 1px solid #e1e5e9;
}

.strength-label {
    font-weight: 600;
    color: #555;
    white-space: nowrap;
}

.strength-bar {
    flex: 1;
    height: 8px;
    background: #e1e5e9;
    border-radius: 4px;
    overflow: hidden;
}

.strength-fill {
    height: 100%;
    border-radius: 4px;
    transition: all 0.3s ease;
    width: 0%;
}

.strength-fill.weak {
    background: #ff6b6b;
    width: 33.33%;
}

.strength-fill.medium {
    background: #ffd93d;
    width: 66.66%;
}

.strength-fill.strong {
    background: #6bcf7f;
    width: 100%;
}

.strength-fill.very-strong {
    background: #4ecdc4;
    width: 100%;
}

#strengthText {
    font-weight: 600;
    min-width: 80px;
    text-align: center;
}

#strengthText.weak {
    color: #ff6b6b;
}

#strengthText.medium {
    color: #ffd93d;
}

#strengthText.strong {
    color: #6bcf7f;
}

#strengthText.very-strong {
    color: #4ecdc4;
}

/* 애니메이션 */
@keyframes fadeIn {
    from {
        opacity: 0;
        transform: translateY(20px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

.container {
    animation: fadeIn 0.6s ease-out;
}

/* 반응형 디자인 */
@media (max-width: 600px) {
    .container {
        padding: 30px 20px;
        margin: 10px;
    }
    
    h1 {
        font-size: 2em;
    }
    
    .password-box {
        flex-direction: column;
    }
    
    .copy-btn {
        width: 100%;
    }
    
    .strength-meter {
        flex-direction: column;
        gap: 10px;
        text-align: center;
    }
    
    .strength-bar {
        width: 100%;
    }
}

/* 다크 모드 지원 */
@media (prefers-color-scheme: dark) {
    body {
        background: linear-gradient(135deg, #2c3e50 0%, #34495e 100%);
    }
    
    .container {
        background: #2c3e50;
        color: white;
    }
    
    h1 {
        color: white;
    }
    
    #password {
        background: #34495e;
        color: white;
        border-color: #4a5568;
    }
    
    .option label {
        color: #e2e8f0;
    }
    
    .strength-meter {
        background: #34495e;
        border-color: #4a5568;
    }
    
    .strength-label {
        color: #e2e8f0;
    }
    
    .lang-select select {
        background: #34495e;
        color: white;
        border-color: #4a5568;
    }
}

/* 접근성 개선 */
@media (prefers-reduced-motion: reduce) {
    * {
        animation-duration: 0.01ms !important;
        animation-iteration-count: 1 !important;
        transition-duration: 0.01ms !important;
    }
}

/* 포커스 표시 개선 */
button:focus,
input:focus,
select:focus {
    outline: 2px solid #667eea;
    outline-offset: 2px;
}

/* 복사 성공 애니메이션 */
.copy-success {
    animation: copyPulse 0.6s ease-out;
}

@keyframes copyPulse {
    0% {
        transform: scale(1);
    }
    50% {
        transform: scale(1.1);
        background: #6bcf7f;
    }
    100% {
        transform: scale(1);
    }
}