:root {
    --primary-color: #4361ee;
    --secondary-color: #3f37c9;
    --success-color: #4cc9f0;
    --error-color: #f72585;
    --light-color: #f8f9fa;
    --dark-color: #212529;
    --border-radius: 12px;
    --box-shadow: 0 10px 20px rgba(0, 0, 0, 0.1);
    --transition: all 0.3s ease;
}

* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
}

body {
    display: flex;
    flex-direction: column;
    align-items: center;
    min-height: 100vh;
    background: linear-gradient(135deg, #f5f7fa 0%, #c3cfe2 100%);
    padding: 20px;
}

.container {
    width: 100%;
    max-width: 500px;
    margin-top: 130px;
    background: white;
    border-radius: var(--border-radius);
    box-shadow: var(--box-shadow);
    padding: 40px;
    text-align: center;
    position: relative;
    overflow: hidden;
}

.container::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 8px;
    background: linear-gradient(90deg, var(--primary-color), var(--success-color));
}

body > i {
    font-size: 200px;
    position: absolute;
    top: 40px;
    z-index: 100;
}

h1 {
    color: var(--dark-color);
    margin-bottom: 10px;
    font-weight: 600;
    margin-top: 100px;
}

.subtitle {
    color: #6c757d;
    margin-bottom: 30px;
    font-size: 16px;
}

.pin-container {
    display: flex;
    justify-content: center;
    gap: 15px;
    margin: 30px 0;
}

.pin-input {
    width: 60px;
    height: 70px;
    text-align: center;
    font-size: 32px;
    font-weight: bold;
    border: 2px solid #e9ecef;
    border-radius: var(--border-radius);
    outline: none;
    transition: var(--transition);
    caret-color: transparent;
}

.pin-input:focus {
    border-color: var(--primary-color);
    box-shadow: 0 0 0 3px rgba(67, 97, 238, 0.2);
}

.pin-input.filled {
    border-color: var(--success-color);
    background-color: rgba(76, 201, 240, 0.05);
}

.pin-input.error {
    border-color: var(--error-color);
    animation: shake 0.5s;
}

@keyframes shake {
    0%, 100% { transform: translateX(0); }
    20%, 60% { transform: translateX(-5px); }
    40%, 80% { transform: translateX(5px); }
}

.actions {
    display: flex;
    justify-content: center;
    gap: 15px;
    margin-top: 30px;
}

.btn {
    padding: 12px 24px;
    border: none;
    border-radius: var(--border-radius);
    font-size: 16px;
    font-weight: 500;
    cursor: pointer;
    transition: var(--transition);
    display: flex;
    align-items: center;
    gap: 8px;
}

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

.btn-primary:hover {
    background: var(--secondary-color);
    transform: translateY(-2px);
}

.btn-secondary {
    background: #e9ecef;
    color: var(--dark-color);
}

.btn-secondary:hover {
    background: #dee2e6;
}

.toggle-visibility {
    margin-top: 15px;
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 8px;
    color: #6c757d;
    font-size: 14px;
    cursor: pointer;
    user-select: none;
}

.toggle-visibility i {
    font-size: 16px;
}

.success-message {
    background: rgba(76, 201, 240, 0.1);
    border: 1px solid var(--success-color);
    color: var(--success-color);
    padding: 15px;
    border-radius: var(--border-radius);
    margin-top: 20px;
    display: none;
}

.error-message {
    background: rgba(247, 37, 133, 0.1);
    border: 1px solid var(--error-color);
    color: var(--error-color);
    padding: 15px;
    border-radius: var(--border-radius);
    margin-top: 20px;
    display: none;
}

.biometric-option {
    margin-top: 20px;
    padding-top: 20px;
    border-top: 1px solid #e9ecef;
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 15px;
}

.biometric-btn {
    background: none;
    border: 2px solid #e9ecef;
    border-radius: 50%;
    width: 50px;
    height: 50px;
    display: flex;
    align-items: center;
    justify-content: center;
    cursor: pointer;
    transition: var(--transition);
}

.biometric-btn:hover {
    border-color: var(--primary-color);
    color: var(--primary-color);
}

.biometric-btn i {
    font-size: 20px;
}

.fas {
    line-height: 1.6;
}

@media (max-width: 480px) {
    .container {
        padding: 30px 20px;
    }
    
    .pin-input {
        width: 50px;
        height: 60px;
        font-size: 28px;
    }
    
    h1 {
        font-size: 24px;
    }
}