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

body {
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "Noto Sans JP", Roboto, "Helvetica Neue", Arial, sans-serif;
    background: linear-gradient(135deg, #F8FAFC 0%, #E2E8F0 100%);
    min-height: 100vh;
    display: flex;
    align-items: center;
    justify-content: center;
    padding: 20px;
}

.login-container {
    width: 100%;
    max-width: 480px;
}

.login-card {
    background: white;
    border-radius: 16px;
    box-shadow: 0 8px 32px rgba(0, 0, 0, 0.1);
    overflow: hidden;
    animation: slideIn 0.5s ease-out;
    border: 1px solid #E2E8F0;
}

@keyframes slideIn {
    from {
        opacity: 0;
        transform: translateY(-20px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

.login-header {
    background: linear-gradient(135deg, #3B82F6 0%, #2563EB 100%);
    color: white;
    padding: 48px 40px;
    text-align: center;
    position: relative;
}

.login-header::after {
    content: '';
    position: absolute;
    bottom: 0;
    left: 0;
    right: 0;
    height: 4px;
    background: linear-gradient(90deg, #60A5FA, #3B82F6, #2563EB);
}

.logo {
    font-size: 72px;
    margin-bottom: 20px;
    filter: drop-shadow(0 4px 8px rgba(0, 0, 0, 0.2));
}

.login-header h1 {
    font-size: 32px;
    font-weight: 700;
    margin-bottom: 12px;
    letter-spacing: -0.5px;
}

.login-header p {
    font-size: 15px;
    opacity: 0.95;
    font-weight: 500;
}

.login-form {
    padding: 48px 40px;
}

.form-group {
    margin-bottom: 28px;
}

.form-group label {
    display: block;
    font-size: 14px;
    font-weight: 600;
    color: #1E293B;
    margin-bottom: 10px;
    letter-spacing: 0.3px;
}

.form-group input {
    width: 100%;
    padding: 14px 18px;
    border: 2px solid #E2E8F0;
    border-radius: 10px;
    font-size: 15px;
    transition: all 0.3s;
    background: #F8FAFC;
    color: #1E293B;
}

.form-group input:hover {
    border-color: #CBD5E1;
    background: white;
}

.form-group input:focus {
    outline: none;
    border-color: #3B82F6;
    background: white;
    box-shadow: 0 0 0 4px rgba(59, 130, 246, 0.1);
}

.error-message {
    background: #FEE2E2;
    border: 1px solid #FCA5A5;
    color: #991B1B;
    padding: 12px 16px;
    border-radius: 8px;
    font-size: 14px;
    margin-bottom: 20px;
    animation: shake 0.5s;
}

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

.btn-login {
    width: 100%;
    background: linear-gradient(135deg, #3B82F6 0%, #2563EB 100%);
    color: white;
    border: none;
    padding: 16px 24px;
    border-radius: 10px;
    font-size: 16px;
    font-weight: 600;
    cursor: pointer;
    transition: all 0.3s;
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 8px;
    box-shadow: 0 4px 12px rgba(59, 130, 246, 0.2);
}

.btn-login:hover {
    transform: translateY(-2px);
    box-shadow: 0 8px 24px rgba(59, 130, 246, 0.35);
    background: linear-gradient(135deg, #2563EB 0%, #1D4ED8 100%);
}

.btn-login:active {
    transform: translateY(0);
    box-shadow: 0 2px 8px rgba(59, 130, 246, 0.3);
}

.spinner {
    width: 16px;
    height: 16px;
    border: 2px solid rgba(255, 255, 255, 0.3);
    border-top: 2px solid white;
    border-radius: 50%;
    animation: spin 0.8s linear infinite;
}

@keyframes spin {
    to { transform: rotate(360deg); }
}

.login-footer {
    background: linear-gradient(135deg, #F8FAFC 0%, #F1F5F9 100%);
    padding: 24px 40px;
    text-align: center;
    color: #64748B;
    font-size: 13px;
    border-top: 1px solid #E2E8F0;
}

.login-info {
    background: #EFF6FF;
    border-left: 4px solid #3B82F6;
    padding: 16px 20px;
    margin-bottom: 24px;
    border-radius: 8px;
}

.login-info p {
    font-size: 13px;
    color: #1E40AF;
    margin: 0;
    line-height: 1.6;
}

/* レスポンシブ */
@media (max-width: 480px) {
    .login-card {
        border-radius: 12px;
    }

    .login-header {
        padding: 32px 24px;
    }

    .logo {
        font-size: 48px;
    }

    .login-header h1 {
        font-size: 24px;
    }

    .login-form {
        padding: 32px 24px;
    }

    .login-footer {
        padding: 16px 24px;
    }
}