/**
 * 诊断系统顶栏 - Burning Math Academy 品牌统一
 * 白/浅灰底、机构感、官网轻入口
 */
.diag-nav--brand {
  background: #ffffff !important;
  border-bottom: 1px solid var(--gray-200, #e5e7eb);
  box-shadow: 0 1px 3px rgba(16, 24, 40, 0.04);
  min-height: 56px;
}

.diag-nav__container {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: space-between;
  gap: var(--space-3, 12px);
  padding-top: 8px;
  padding-bottom: 8px;
}

.diag-nav__brand {
  display: inline-flex;
  align-items: center;
  gap: var(--space-3, 12px);
  text-decoration: none;
  color: var(--gray-900, #111827);
}
.diag-nav__brand:hover {
  color: var(--gray-900, #111827);
}

.diag-nav__logo {
  width: 36px;
  height: 36px;
  object-fit: contain;
}

.diag-nav__brand-text {
  display: flex;
  flex-direction: column;
  align-items: flex-start;
  gap: 0;
  line-height: 1.2;
}

.diag-nav__brand-name {
  font-size: 17px;
  font-weight: 700;
  color: var(--gray-900, #111827);
  letter-spacing: -0.02em;
}

.diag-nav__brand-sub {
  font-size: 11px;
  font-weight: 500;
  color: var(--gray-500, #6b7280);
  margin-top: 1px;
}

.diag-nav__toggler {
  display: none;
  width: 40px;
  height: 40px;
  padding: 0;
  border: 1px solid var(--gray-200);
  border-radius: var(--radius-md, 8px);
  background: #fff;
  cursor: pointer;
  align-items: center;
  justify-content: center;
}
.diag-nav__toggler-icon {
  display: block;
  width: 18px;
  height: 2px;
  background: var(--gray-700);
  box-shadow: 0 6px 0 var(--gray-700), 0 -6px 0 var(--gray-700);
}

.diag-nav__collapse {
  flex-grow: 1;
  justify-content: space-between;
  align-items: center;
}

@media (max-width: 991px) {
  .diag-nav__toggler { display: inline-flex; }
  .diag-nav__collapse {
    flex-basis: 100%;
    order: 3;
    margin-top: var(--space-2);
    padding-top: var(--space-3);
    border-top: 1px solid var(--gray-200);
  }
  .diag-nav__main,
  .diag-nav__right {
    flex-direction: column;
    align-items: flex-start;
    width: 100%;
  }
  .diag-nav__item { width: 100%; }
  .diag-nav__link,
  .diag-nav__user {
    display: block;
    padding: var(--space-2) 0;
    width: 100%;
  }
}

.diag-nav__main,
.diag-nav__right {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: var(--space-1, 4px) var(--space-4, 16px);
  list-style: none;
  margin: 0;
  padding: 0;
}

.diag-nav__link {
  font-size: 14px;
  font-weight: 500;
  color: var(--gray-600, #4b5563);
  text-decoration: none;
  padding: var(--space-2, 8px) var(--space-3, 12px);
  border-radius: var(--radius-sm, 6px);
  transition: color 0.2s, background 0.2s;
}
.diag-nav__link:hover {
  color: var(--primary, #2563eb);
  background: var(--gray-50, #f9fafb);
}
.diag-nav__link--active {
  color: var(--primary, #2563eb);
  font-weight: 600;
  position: relative;
}
.diag-nav__link--active::after {
  content: "";
  position: absolute;
  left: var(--space-3);
  right: var(--space-3);
  bottom: 4px;
  height: 2px;
  background: var(--primary, #2563eb);
  border-radius: 1px;
}

.diag-nav__link--light {
  color: var(--gray-500, #6b7280);
  font-weight: 500;
}
.diag-nav__link--light:hover {
  color: var(--primary, #2563eb);
}

.diag-nav__user {
  font-size: 13px;
  color: var(--gray-600, #4b5563);
  padding: var(--space-2) var(--space-3);
}

/* 登录/注册页顶栏保持同风格，不额外加类 */
.diag-nav.auth-page-nav {
  background: #ffffff !important;
}