.activity-detail {
  max-width: 1200px;
  margin: 20px auto 0;
  padding: 30px;
  background: #fff;
  border-radius: 8px;
  box-shadow: 0 2px 10px rgba(0, 0, 0, 0.1);
}

.activity-header {
  display: flex;
  align-items: flex-start;
  gap: 30px;
  border-bottom: 2px solid #f0f0f0;
  padding-bottom: 30px;
  margin-bottom: 30px;
}

.activity-info {
  flex: 1;
}

.activity-image-container {
  flex-shrink: 0;
}

.activity-title {
  display: flex;
  align-items: center;
  font-size: 28px;
  font-weight: bold;
  color: #333;
  margin-bottom: 15px;
  line-height: 1.4;
}

.activity-status {
  display: inline-block;
  padding: 4px 12px;
  border-radius: 20px;
  font-size: 12px;
  font-weight: bold;
  margin-left: 20px;
}

.activity-meta {
  display: flex;
  flex-direction: column;
  gap: 12px;
}

.meta-item {
  display: flex;
  align-items: center;
  color: #666;
  font-size: 14px;
}

.meta-item i {
  margin-right: 8px;
  color: #007bff;
}

.status-upcoming {
  background: #e3f2fd;
  color: #1976d2;
}

.status-ongoing {
  background: #e8f5e8;
  color: #388e3c;
}

.status-completed {
  background: #f5f5f5;
  color: #666;
}

.activity-image {
  width: 327px;
  height: 180px;
  object-fit: cover;
  border-radius: 8px;
  margin-bottom: 30px;
}

.activity-content {
  line-height: 1.8;
  color: #333;
  font-size: 16px;
}

.signup-section {
  background: #f8f9fa;
  border: 1px solid #e9ecef;
  border-radius: 8px;
  padding: 20px;
  margin: 20px 0;
  text-align: center;
}

.signup-btn {
  background: #007bff;
  color: white;
  border: none;
  padding: 12px 30px;
  border-radius: 5px;
  font-size: 16px;
  cursor: pointer;
  transition: background-color 0.3s;
}

.signup-btn:hover {
  background: #0056b3;
}

.signup-status {
  color: #28a745;
  font-weight: bold;
  font-size: 16px;
}

/* 报名弹窗样式 */
.signup-modal {
  display: none;
  position: fixed;
  z-index: 1000;
  left: 0;
  top: 0;
  width: 100%;
  height: 100%;
  background-color: rgba(0, 0, 0, 0.5);
}

.signup-modal-content {
  background-color: #fff;
  margin: calc(50vh - 256px) auto 0;
  padding: 30px;
  border-radius: 8px;
  width: 90%;
  max-width: 500px;
  position: relative;
}

.signup-modal h3 {
  margin-top: 0;
  margin-bottom: 20px;
  color: #333;
  text-align: center;
}

.signup-form {
  display: flex;
  flex-direction: column;
  gap: 15px;
}

.form-group {
  display: flex;
  flex-direction: column;
}

.form-group label {
  margin-bottom: 5px;
  font-weight: bold;
  color: #333;
}

.form-group input {
  padding: 10px;
  border: 1px solid #ddd;
  border-radius: 4px;
  font-size: 14px;
}

.form-group input:focus {
  outline: none;
  border-color: #007bff;
  box-shadow: 0 0 0 2px rgba(0, 123, 255, 0.25);
}

.form-actions {
  display: flex;
  gap: 10px;
  justify-content: center;
  margin-top: 20px;
}

.form-actions button {
  padding: 10px 20px;
  border: none;
  border-radius: 4px;
  cursor: pointer;
  font-size: 14px;
}

.btn-primary {
  background: #007bff;
  color: white;
}

.btn-primary:hover {
  background: #0056b3;
}

.btn-secondary {
  background: #6c757d;
  color: white;
}

.btn-secondary:hover {
  background: #545b62;
}

.close-btn {
  position: absolute;
  right: 15px;
  top: 15px;
  font-size: 24px;
  font-weight: bold;
  color: #aaa;
  cursor: pointer;
}

.close-btn:hover {
  color: #000;
}

.activity-content h1,
.activity-content h2,
.activity-content h3 {
  margin-top: 30px;
  margin-bottom: 15px;
  color: #333;
}

.activity-content p {
  margin-bottom: 15px;
}

.activity-content img {
  max-width: 100%;
  height: auto;
  border-radius: 4px;
  margin: 15px 0;
}

.loading {
  text-align: center;
  padding: 50px;
  color: #666;
}

.error {
  text-align: center;
  padding: 50px;
  color: #d32f2f;
}

@media (max-width: 768px) {
  .activity-detail {
    margin: 10px;
    padding: 15px;
  }

  .activity-header {
    flex-direction: column;
    gap: 20px;
  }

  .activity-title {
    font-size: 24px;
  }

  .activity-meta {
    gap: 10px;
  }

  .activity-image {
    width: 100%;
    max-width: 327px;
    height: 180px;
  }
}