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

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, 'Helvetica Neue', Arial, sans-serif;
    background-color: #f5f5f5;
    min-height: 100vh;
    display: flex;
    align-items: center;
    justify-content: center;
}

.container {
    text-align: center;
    padding: 1rem;
}

.logo {
    display: block;
    margin: 0 auto 3.5rem;
    width: 307px;
    height: 30px;
    object-fit: contain;
}

.login-button {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: 12px;
    background-color: #2F2F2F;
    color: white;
    padding: 16px;
    border: none;
    border-radius: 12px;
    font-family: 'Hiragino Kaku Gothic ProN', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
    font-size: 13px;
    font-weight: 600;
    line-height: 100%;
    letter-spacing: 0.02em;
    cursor: pointer;
    transition: background-color 0.2s ease;
    text-decoration: none;
    width: 289px;
    height: 56px;
}
.login-button:hover {
    background-color: #1a1a1a;
}

.login-button:active {
    background-color: #000000;
}

.login-button:disabled {
    background-color: #1a1a1a;
    cursor: not-allowed;
    opacity: 0.8;
}

.microsoft-icon {
    width: 24px;
    height: 24px;
    background: url('data:image/svg+xml;base64,PHN2ZyB3aWR0aD0iMjAiIGhlaWdodD0iMjAiIHZpZXdCb3g9IjAgMCAyMCAyMCIgZmlsbD0ibm9uZSIgeG1sbnM9Imh0dHA6Ly93d3cudzMub3JnLzIwMDAvc3ZnIj4KPHJlY3Qgd2lkdGg9IjkuNSIgaGVpZ2h0PSI5LjUiIGZpbGw9IiNGMjUwMjIiLz4KPHJlY3QgeD0iMTAuNSIgd2lkdGg9IjkuNSIgaGVpZ2h0PSI5LjUiIGZpbGw9IiM3RkJBMDAiLz4KPHJlY3QgeT0iMTAuNSIgd2lkdGg9IjkuNSIgaGVpZ2h0PSI5LjUiIGZpbGw9IiMwMEE0RUYiLz4KPHJlY3QgeD0iMTAuNSIgeT0iMTAuNSIgd2lkdGg9IjkuNSIgaGVpZ2h0PSI5LjUiIGZpbGw9IiNGRkI5MDAiLz4KPC9zdmc+') no-repeat center;
    background-size: contain;
}

.loader {
    width: 24px;
    height: 24px;
    border: 3px solid rgba(255, 255, 255, 0.3);
    border-top-color: white;
    border-radius: 50%;
    animation: spin 0.8s linear infinite;
}

/* PC (768px以上) */
@media (min-width: 768px) {
    .logo {
        width: 640px;
        height: 64px;
        margin: 0 auto 5rem;
    }

    .login-button {
        width: 326px;
        height: 64px;
        gap: 16px;
        border-radius: 16px;
        padding: 16px 20px;
        font-size: 14px;
    }

    .microsoft-icon {
        width: 32px;
        height: 32px;
    }

    .loader {
        width: 32px;
        height: 32px;
    }
}


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