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

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

.login-container {
    background: white;
    border-radius: 16px;
    box-shadow: 0 20px 60px rgba(0, 0, 0, 0.3);
    padding: 40px;
    max-width: 400px;
    width: 100%;
}

.login-header {
    text-align: center;
    margin-bottom: 30px;
}

.login-icon {
    font-size: 60px;
    margin-bottom: 15px;
}

h1 {
    color: #333;
    font-size: 24px;
    margin-bottom: 10px;
}

.subtitle {
    color: #666;
    font-size: 14px;
}

.pin-input-group {
    display: flex;
    gap: 10px;
    justify-content: center;
    margin: 30px 0;
}

.pin-digit {
    width: 60px;
    min-width: 0;
    flex: 0 1 60px;
    height: 70px;
    font-size: 32px;
    text-align: center;
    border: 2px solid #ddd;
    border-radius: 12px;
    outline: none;
    transition: all 0.3s;
    font-weight: 600;
}

.pin-digit:focus {
    border-color: #667eea;
    box-shadow: 0 0 0 3px rgba(102, 126, 234, 0.1);
}

.pin-digit.error {
    border-color: #dc3545;
    animation: shake 0.5s;
}

@keyframes shake {
    0%, 100% { transform: translateX(0); }
    25% { transform: translateX(-10px); }
    75% { transform: translateX(10px); }
}

.error-message {
    color: #dc3545;
    text-align: center;
    margin-top: 15px;
    font-size: 14px;
    font-weight: 500;
    display: none;
}

.error-message.show {
    display: block;
}

.login-btn {
    width: 100%;
    padding: 15px;
    background: #667eea;
    color: white;
    border: none;
    border-radius: 10px;
    font-size: 16px;
    font-weight: 600;
    cursor: pointer;
    transition: all 0.3s;
    margin-top: 20px;
}

.login-btn:hover:not(:disabled) {
    background: #5568d3;
    transform: translateY(-2px);
    box-shadow: 0 5px 15px rgba(102, 126, 234, 0.3);
}

.login-btn:active:not(:disabled) {
    transform: translateY(0);
}

.login-btn:disabled {
    background: #ccc;
    cursor: not-allowed;
    transform: none;
}

@media (max-width: 480px) {
    .login-container {
        padding: 30px 20px;
    }

    .pin-digit {
        height: 60px;
        font-size: 28px;
    }

    .pin-input-group {
        gap: 8px;
    }
}