* {
  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);
  }
}