/* =========================================================
   清晨教育 - 关于我们 页面样式
   基于 style.css 蓝白色调扩展
   ========================================================= */

/* ---------- 导航搜索框（与参考页面一致） ---------- */
.main-nav { display: flex; align-items: center; gap: 12px; }
.main-nav ul { flex: 1; justify-content: flex-end; }
.nav-search {
  display: flex;
  align-items: center;
  flex-shrink: 0;
  border: 1px solid var(--border);
  border-radius: 999px;
  overflow: hidden;
  background: var(--bg-alt);
  transition: var(--transition);
}
.nav-search:focus-within { border-color: var(--blue); background: var(--white); }
.nav-search input {
  border: none;
  outline: none;
  background: transparent;
  padding: 8px 4px 8px 16px;
  font-size: 14px;
  width: 150px;
  font-family: inherit;
  color: var(--text);
}
.nav-search button {
  border: none;
  background: transparent;
  cursor: pointer;
  padding: 8px 12px 8px 6px;
  font-size: 14px;
}

/* ---------- Banner 满屏大图 ---------- */
.about-banner {
  position: relative;
  width: 100%;
  height: 700px;
  overflow: hidden;
  display: flex;
  align-items: center;
}
.about-banner-bg,
.about-banner-bg img {
  position: absolute;
  inset: 0;
  width: 100%;
  height: 100%;
}
.about-banner-bg img {
  object-fit: cover;
  object-position: center;
}
.about-banner-mask {
  position: absolute;
  inset: 0;
  background: linear-gradient(100deg, rgba(10, 37, 64, 0.88) 0%, rgba(10, 76, 176, 0.62) 45%, rgba(11, 99, 229, 0.25) 100%);
}
.about-banner-inner {
  position: relative;
  z-index: 2;
  color: var(--white);
}
.about-banner-inner .hero-tag {
  background: rgba(255, 255, 255, 0.14);
  color: var(--white);
  border: 1px solid rgba(255, 255, 255, 0.35);
  backdrop-filter: blur(4px);
}
.about-banner-inner h1 {
  font-size: 42px;
  line-height: 1.35;
  letter-spacing: 2px;
  margin-bottom: 16px;
  text-shadow: 0 4px 24px rgba(10, 37, 64, 0.45);
}
.about-banner-inner p {
  font-size: 18px;
  color: rgba(255, 255, 255, 0.88);
}

/* ---------- Tab 切换（关于我们整页切换） ---------- */
.about-tab-btns {
  margin-top: 44px;
  margin-bottom: 0;
}
/* 覆盖 style.css 中 .tab-panel 的卡片式布局，改为整页内容容器 */
.about-tabs > .tab-panel {
  display: none;
  grid-template-columns: none;
  gap: 0;
  align-items: initial;
  background: transparent;
  border: none;
  border-radius: 0;
  padding: 0;
  box-shadow: none;
}
.about-tabs > .tab-panel.active {
  display: block;
  animation: fadeUp 0.45s ease;
}
.about-tabs > .tab-panel .section:first-child {
  padding-top: 64px;
}
.about-tabs > .tab-panel .section:last-child {
  padding-bottom: 88px;
}

/* ---------- 公司简介 ---------- */
.about-intro-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 48px;
  align-items: center;
}
.about-intro-media {
  width: 100%;
  max-width: 627px;
  margin: 0;
}
.about-intro-media img {
  border-radius: var(--radius);
  box-shadow: var(--shadow-hover);
  width: 100%;
  aspect-ratio: 3/2;
  object-fit: cover;
}
.about-intro-media video {
  display: block;
  width: 100%;
  max-width: 627px;
  height: auto;
  aspect-ratio: 16 / 10;
  object-fit: cover;
  cursor: pointer;
  background: #000;
  border-radius: var(--radius);
  box-shadow: var(--shadow-hover);
}
.about-intro-body h3 {
  font-size: 24px;
  color: var(--blue-deep);
  margin-bottom: 16px;
}
.about-intro-body p {
  color: var(--text-sub);
  font-size: 16px;
  line-height: 2;
  text-align: justify;
  text-indent: 2em;
}

/* ---------- 数据统计（4 项） ---------- */
.about-stats { margin: 56px 0 0; }
.about-stats-list {
  display: grid;
  grid-template-columns: repeat(5, 1fr);
  gap: 20px;
  text-align: center;
}
.about-stats-item strong {
  display: block;
  font-size: 22px;
  color: #5ea2ff;
  line-height: 1.2;
}
.about-stats-item span {
  font-size: 13px;
  color: rgba(255, 255, 255, 0.78);
}

/* ---------- 服务特色 Bento 网格（左 2 右 1） ---------- */
.service-bento {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 24px;
  align-items: start;
}
.service-bento-col {
  display: grid;
  grid-template-rows: auto auto;
  gap: 24px;
}
.service-card {
  display: flex;
  flex-direction: column;
  border-radius: 20px;
  overflow: hidden;
  transition: var(--transition);
}
.service-card:hover { box-shadow: var(--shadow-hover); transform: translateY(-6px); }
.service-card-light {
  background: var(--white);
  border: 1px solid var(--border);
}
.service-card-feature {
  background: linear-gradient(150deg, var(--blue) 0%, var(--blue-dark) 55%, var(--blue-deep) 100%);
  color: var(--white);
}
.service-card-text { padding: 28px 28px 0; }
.service-card-text h3 {
  font-size: 21px;
  color: var(--blue-deep);
  margin-bottom: 8px;
  line-height: 1.4;
}
.service-card-text p { font-size: 14px; color: var(--text-sub); line-height: 1.7; }
.service-card-feature .service-card-text h3 { color: var(--white); }
.service-card-feature .service-card-text p { color: rgba(255, 255, 255, 0.85); }
.service-card img {
  width: 100%;
  flex: none;
  object-fit: cover;
  display: block;
}
.service-card-light img { width: 100%;
  flex: none;
  object-fit: cover;
  display: block;
}
.service-card-feature img {width: 100%;
  -webkit-mask-image: linear-gradient(180deg, #000 82%, #000 100%);

 
}

/* ---------- 师资团队卡片间距 ---------- */
.teacher-grid .teacher-card img {
  width: 100%;
  aspect-ratio: 1/1;
  object-fit: cover;
}

/* ---------- 课程特色 / 覆盖行业 ---------- */
.industry-layout {
  display: grid;
  grid-template-columns: 1.05fr 1fr;
  gap: 48px;
  align-items: center;
}
.industry-subtitle {
  font-size: 20px;
  color: var(--blue-deep);
  margin-bottom: 20px;
}
.industry-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 14px;
}
.industry-grid li {
  display: flex;
  align-items: center;
  gap: 10px;
  background: var(--white);
  border: 1px solid var(--border);
  border-radius: 10px;
  padding: 14px 14px;
  font-size: 15px;
  font-weight: 600;
  color: var(--text);
  transition: var(--transition);
}
.industry-grid li:hover {
  box-shadow: var(--shadow-hover);
  transform: translateY(-4px);
  border-color: transparent;
  color: var(--blue);
}
.industry-icon {
  flex-shrink: 0;
  width: 38px;
  height: 38px;
  display: flex;
  align-items: center;
  justify-content: center;
  background: var(--blue-light);
  border-radius: 10px;
  color: var(--blue);
}
.industry-icon svg { width: 20px; height: 20px; }
.industry-note {
  margin-top: 20px;
  font-size: 16px;
  font-weight: 600;
  color: var(--blue-deep);
  background: var(--blue-light);
  border-radius: 999px;
  padding: 14px 24px;
  text-align: center;
}
.industry-media img {
  border-radius: var(--radius);
  box-shadow: var(--shadow-hover);
  width: 100%;
  aspect-ratio: 4/3;
  object-fit: cover;
}

/* ---------- 授课模式流程 ---------- */
.teach-flow {
  display: flex;
  align-items: stretch;
  justify-content: center;
  gap: 12px;
  flex-wrap: wrap;
  margin-bottom: 56px;
}
.teach-flow li:not(.teach-flow-arrow) {
  background: var(--white);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 20px 24px;
  text-align: center;
  min-width: 160px;
  font-size: 16px;
  font-weight: 600;
  color: var(--blue-deep);
  box-shadow: var(--shadow);
  transition: var(--transition);
}
.teach-flow li:not(.teach-flow-arrow):hover {
  box-shadow: var(--shadow-hover);
  transform: translateY(-4px);
}
.teach-flow-num {
  display: block;
  font-size: 22px;
  font-weight: 800;
  color: var(--blue);
  margin-bottom: 6px;
}
.teach-flow-arrow {
  align-self: center;
  color: var(--blue);
  font-size: 22px;
  font-weight: 700;
}

/* ---------- 01-04 步骤卡片 ---------- */
.about-steps { align-items: stretch; }
.step-card {
  background: var(--white);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 30px 26px;
  transition: var(--transition);
  position: relative;
  overflow: hidden;
}
.step-card::before {
  content: "";
  position: absolute;
  top: 0; left: 0;
  width: 100%; height: 4px;
  background: linear-gradient(90deg, var(--blue), #5ea2ff);
  transform: scaleX(0);
  transform-origin: left;
  transition: var(--transition);
}
.step-card:hover { box-shadow: var(--shadow-hover); transform: translateY(-6px); }
.step-card:hover::before { transform: scaleX(1); }
.step-num {
  font-size: 34px;
  font-weight: 800;
  color: var(--blue-light);
  -webkit-text-stroke: 1px var(--blue);
  display: block;
  margin-bottom: 12px;
}
.step-card h3 {
  font-size: 20px;
  color: var(--blue-deep);
  margin-bottom: 12px;
}
.step-card .check-list { margin-bottom: 0; }

/* ---------- 加入我们 ---------- */
.join-grid {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 24px;
  margin-bottom: 48px;
}
.join-benefits {
  display: grid;
  grid-template-columns: minmax(0, 1fr) 330px;
  gap: 48px;
  align-items: center;
  background: var(--white);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  box-shadow: var(--shadow);
  padding: 40px;
}
.join-benefits-copy { min-width: 0; }
.join-benefits h3 {
  font-size: 22px;
  color: var(--blue-deep);
  margin-bottom: 20px;
  text-align: left;
}
.join-benefits .check-list { max-width: 720px; margin: 0; }
.join-benefit-list {
  display: grid;
  grid-template-columns: 1fr;
  gap: 10px;
}
.join-contact {
  position: relative;
  display: flex;
  flex-direction: column;
  align-items: flex-start;
  width: 100%;
  min-height: 236px;
  margin: 0;
  padding: 28px;
  overflow: hidden;
  border: 1px solid #cddff5;
  border-radius: 14px;
  background:
    radial-gradient(circle at 100% 0, rgba(11, 99, 229, .12), transparent 44%),
    linear-gradient(145deg, #f7fbff 0%, #eef5ff 100%);
  box-shadow: 0 12px 30px rgba(10, 37, 64, .09);
}
.join-contact::after {
  content: "";
  position: absolute;
  right: -24px;
  bottom: -36px;
  width: 120px;
  height: 120px;
  border: 18px solid rgba(11, 99, 229, .055);
  border-radius: 50%;
  pointer-events: none;
}
.join-contact-icon {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 46px;
  height: 46px;
  margin-bottom: 22px;
  border-radius: 12px;
  background: var(--blue);
  color: var(--white);
  box-shadow: 0 8px 20px rgba(11, 99, 229, .22);
}
.join-contact-icon svg {
  width: 23px;
  height: 23px;
}
.join-contact-label {
  margin-bottom: 7px;
  color: var(--text-sub);
  font-size: 12px;
  font-weight: 650;
  letter-spacing: .12em;
}
.join-contact-email {
  position: relative;
  z-index: 1;
  display: block;
  max-width: 100%;
  color: var(--blue-deep);
  font-size: 16px;
  font-weight: 700;
  line-height: 1.45;
  overflow-wrap: anywhere;
  text-decoration: none;
  transition: color .2s ease;
}
.join-contact-email:hover {
  color: var(--blue);
  text-decoration: underline;
  text-underline-offset: 4px;
}
.join-contact-email:focus-visible {
  outline: 3px solid rgba(11, 99, 229, .24);
  outline-offset: 5px;
  border-radius: 3px;
}
.join-contact-hint {
  position: relative;
  z-index: 1;
  margin-top: auto;
  padding-top: 20px;
  color: #72849a;
  font-size: 12px;
  line-height: 1.6;
}

/* ---------- 联系我们 ---------- */
.contact-grid {
  display: grid;
  grid-template-columns: 1.2fr 1fr;
  gap: 48px;
  align-items: center;
  background: var(--white);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  box-shadow: var(--shadow);
  padding: 48px;
}
.contact-list li {
  padding: 14px 0;
  border-bottom: 1px dashed var(--border);
  display: flex;
  align-items: baseline;
  gap: 20px;
}
.contact-list li:last-child { border-bottom: none; }
.contact-label {
  flex-shrink: 0;
  width: 76px;
  font-size: 14px;
  color: var(--text-sub);
}
.contact-list strong { font-size: 16px; color: var(--blue-deep); }
.contact-qr {
  display: flex;
  gap: 32px;
  justify-content: center;
}
.contact-qr-item { text-align: center; }
.contact-qr-item img {
  width: 128px;
  height: 128px;
  background: #fff;
  border: 1px solid var(--border);
  border-radius: 12px;
  padding: 8px;
  margin-bottom: 10px;
}
.contact-qr-item p { font-size: 13px; color: var(--text-sub); line-height: 1.6; }

/* ---------- 校长信箱 ---------- */
.principal-mailbox {
  position: relative;
  overflow: hidden;
  background:
    radial-gradient(circle at 8% 18%, rgba(11, 99, 229, 0.08), transparent 28%),
    #f3f7fc;
}
.principal-mailbox [hidden] { display: none !important; }
.principal-mailbox-layout {
  display: grid;
  grid-template-columns: minmax(0, 0.92fr) minmax(0, 1.08fr);
  max-width: 1120px;
  margin: 0 auto;
  overflow: hidden;
  border: 1px solid #dbe6f3;
  border-radius: 18px;
  background: var(--white);
  box-shadow: 0 18px 50px rgba(10, 37, 64, 0.1);
}
.principal-mailbox-intro {
  position: relative;
  min-width: 0;
  padding: 54px 48px 48px;
  overflow: hidden;
  color: var(--white);
  background: linear-gradient(145deg, #0a2d52 0%, #0a2540 60%, #071b2e 100%);
}
.principal-mailbox-intro::before {
  position: absolute;
  inset: 0;
  background-image:
    linear-gradient(rgba(255, 255, 255, 0.045) 1px, transparent 1px),
    linear-gradient(90deg, rgba(255, 255, 255, 0.045) 1px, transparent 1px);
  background-size: 32px 32px;
  content: "";
  pointer-events: none;
}
.principal-mailbox-intro::after {
  position: absolute;
  right: -88px;
  bottom: -94px;
  width: 250px;
  height: 250px;
  border: 1px solid rgba(255, 255, 255, 0.11);
  border-radius: 50%;
  box-shadow:
    0 0 0 36px rgba(255, 255, 255, 0.025),
    0 0 0 72px rgba(255, 255, 255, 0.018);
  content: "";
  pointer-events: none;
}
.principal-mailbox-intro > * {
  position: relative;
  z-index: 1;
}
.principal-mailbox-seal {
  display: flex;
  align-items: center;
  justify-content: center;
  width: 62px;
  height: 62px;
  margin-bottom: 26px;
  border: 1px solid rgba(240, 170, 69, 0.55);
  border-radius: 50%;
  background: rgba(240, 170, 69, 0.1);
  color: #f0aa45;
  box-shadow: 0 0 0 7px rgba(240, 170, 69, 0.05);
}
.principal-mailbox-seal svg { width: 34px; height: 34px; }
.principal-mailbox-eyebrow {
  margin-bottom: 12px;
  color: #93bdee;
  font-size: 12px;
  font-weight: 600;
  letter-spacing: 0.12em;
  line-height: 1.6;
}
.principal-mailbox-intro h2 {
  margin: 0 0 18px;
  color: var(--white);
  font-size: 34px;
  font-weight: 700;
  letter-spacing: 0.01em;
  line-height: 1.38;
}
.principal-mailbox-lead {
  margin: 0;
  color: rgba(255, 255, 255, 0.74);
  font-size: 15px;
  line-height: 1.9;
}
.principal-mailbox-points {
  display: grid;
  gap: 11px;
  margin: 28px 0 0;
}
.principal-mailbox-points li {
  position: relative;
  padding-left: 24px;
  color: rgba(255, 255, 255, 0.9);
  font-size: 14px;
  line-height: 1.65;
}
.principal-mailbox-points li::before {
  position: absolute;
  top: 0.52em;
  left: 2px;
  width: 9px;
  height: 9px;
  border: 1px solid #f0aa45;
  border-radius: 50%;
  box-shadow: inset 0 0 0 2px #0a2540;
  background: #f0aa45;
  content: "";
}
.principal-mailbox-privacy {
  margin: 28px 0 0;
  padding-top: 20px;
  border-top: 1px solid rgba(255, 255, 255, 0.13);
  color: rgba(255, 255, 255, 0.49);
  font-size: 12px;
  line-height: 1.7;
}
.principal-mailbox-card {
  display: flex;
  flex-direction: column;
  justify-content: center;
  min-width: 0;
  padding: 42px 46px;
  background: var(--white);
}
.principal-mailbox-card-head {
  display: flex;
  align-items: flex-start;
  justify-content: space-between;
  gap: 20px;
  margin-bottom: 26px;
}
.principal-mailbox-card-label {
  display: block;
  margin-bottom: 7px;
  color: var(--blue);
  font-size: 12px;
  font-weight: 700;
  letter-spacing: 0.12em;
}
.principal-mailbox-card-head h3 {
  margin: 0;
  color: var(--blue-deep);
  font-size: 22px;
  font-weight: 700;
  line-height: 1.45;
}
.principal-mailbox-required-note {
  flex-shrink: 0;
  padding-top: 2px;
  color: #8391a2;
  font-size: 12px;
  line-height: 1.6;
}
.principal-mailbox-required-note i { color: #d44b3d; font-style: normal; }
.principal-mailbox-form {
  display: grid;
  gap: 18px;
}
.principal-mailbox-field {
  min-width: 0;
}
.principal-mailbox-field label {
  display: inline-block;
  margin-bottom: 7px;
  color: #354b65;
  font-size: 14px;
  font-weight: 600;
  line-height: 1.5;
}
.principal-mailbox-field label > span { color: #d44b3d; }
.principal-mailbox-label-row {
  display: flex;
  align-items: baseline;
  justify-content: space-between;
  gap: 16px;
}
.principal-mailbox-label-row > span {
  color: #93a1b1;
  font-size: 12px;
  line-height: 1.5;
}
.principal-mailbox-field > input,
.principal-mailbox-field > textarea,
.principal-mailbox-field > .principal-mailbox-select-wrap .principal-mailbox-select-trigger {
  display: block;
  width: 100%;
  min-height: 46px;
  margin: 0;
  padding: 11px 13px;
  border: 1px solid #d5e0eb;
  border-radius: 6px;
  outline: none;
  background: #fbfdff;
  color: var(--blue-deep);
  font-family: inherit;
  font-size: 16px;
  line-height: 1.5;
  transition: border-color 0.18s ease, box-shadow 0.18s ease, background-color 0.18s ease;
}
.principal-mailbox-field > input::placeholder,
.principal-mailbox-field > textarea::placeholder {
  color: #9aa8b8;
}
.principal-mailbox-field > input:hover,
.principal-mailbox-field > textarea:hover,
.principal-mailbox-field > .principal-mailbox-select-wrap .principal-mailbox-select-trigger:hover {
  border-color: #adc0d5;
}
.principal-mailbox-field > input:focus,
.principal-mailbox-field > textarea:focus,
.principal-mailbox-field > .principal-mailbox-select-wrap .principal-mailbox-select-trigger:focus {
  border-color: var(--blue);
  background: var(--white);
  box-shadow: 0 0 0 3px rgba(11, 99, 229, 0.1);
}
.principal-mailbox-field > textarea {
  min-height: 158px;
  resize: vertical;
}
.principal-mailbox-select-wrap {
  position: relative;
}
.principal-mailbox-select-trigger {
  display: flex !important;
  align-items: center;
  justify-content: space-between;
  gap: 12px;
  text-align: left;
  cursor: pointer;
}
.principal-mailbox-select-trigger .is-placeholder { color: #9aa8b8; }
.principal-mailbox-select-trigger svg {
  flex: 0 0 16px;
  width: 16px;
  height: 16px;
  color: #70839a;
  transition: transform 0.18s ease;
  pointer-events: none;
}
.principal-mailbox-select-trigger[aria-expanded="true"] svg { transform: rotate(180deg); }
.principal-mailbox-options {
  position: absolute;
  z-index: 30;
  top: calc(100% + 6px);
  right: 0;
  left: 0;
  max-height: 238px;
  margin: 0;
  padding: 6px;
  overflow-y: auto;
  border: 1px solid #cfdae7;
  border-radius: 7px;
  background: var(--white);
  box-shadow: 0 14px 32px rgba(10, 37, 64, 0.16);
}
.principal-mailbox-options [role="option"] {
  position: relative;
  margin: 0;
  padding: 10px 38px 10px 12px;
  border-radius: 5px;
  outline: none;
  color: #40546b;
  font-size: 15px;
  line-height: 1.5;
  cursor: pointer;
}
.principal-mailbox-options [role="option"]:hover,
.principal-mailbox-options [role="option"]:focus {
  background: #eef5ff;
  color: var(--blue);
}
.principal-mailbox-options [role="option"][aria-selected="true"] {
  background: var(--blue-light);
  color: var(--blue);
  font-weight: 600;
}
.principal-mailbox-options [role="option"][aria-selected="true"]::after {
  position: absolute;
  top: 50%;
  right: 13px;
  content: "✓";
  font-size: 14px;
  font-weight: 700;
  transform: translateY(-50%);
}
.principal-mailbox-hint {
  margin: 7px 0 0;
  color: #8493a5;
  font-size: 12px;
  line-height: 1.6;
}
.principal-mailbox-status {
  padding: 11px 13px;
  border: 1px solid #efc9c4;
  border-radius: 6px;
  background: #fff6f5;
  color: #a4362c;
  font-size: 13px;
  line-height: 1.6;
}
.principal-mailbox-submit {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 9px;
  width: 100%;
  min-height: 50px;
  padding: 13px 24px;
  border: 1px solid var(--blue);
  border-radius: 6px;
  background: var(--blue);
  color: var(--white);
  font-family: inherit;
  font-weight: 600;
  cursor: pointer;
  box-shadow: 0 8px 20px rgba(11, 99, 229, 0.19);
  transition: background-color 0.18s ease, transform 0.18s ease, box-shadow 0.18s ease;
}
.principal-mailbox-submit svg {
  width: 19px;
  height: 19px;
  transition: transform 0.18s ease;
}
.principal-mailbox-submit:hover {
  border-color: var(--blue-dark);
  background: var(--blue-dark);
  transform: translateY(-1px);
  box-shadow: 0 10px 24px rgba(11, 99, 229, 0.24);
}
.principal-mailbox-submit:hover svg { transform: translateX(3px); }
.principal-mailbox-submit:focus-visible,
.principal-mailbox-again:focus-visible {
  outline: 3px solid rgba(11, 99, 229, 0.25);
  outline-offset: 3px;
}
.principal-mailbox-submit:disabled {
  cursor: wait;
  opacity: 0.7;
  transform: none;
}
.principal-mailbox-success {
  padding: 26px 0 10px;
  text-align: center;
}
.principal-mailbox-success-icon {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 64px;
  height: 64px;
  margin-bottom: 18px;
  border: 1px solid #b8d7c4;
  border-radius: 50%;
  background: #edf8f1;
  color: #26864b;
}
.principal-mailbox-success-icon svg { width: 32px; height: 32px; }
.principal-mailbox-success h3 {
  margin: 0 0 10px;
  color: var(--blue-deep);
  font-size: 23px;
  line-height: 1.45;
}
.principal-mailbox-success p {
  max-width: 390px;
  margin: 0 auto;
  color: var(--text-sub);
  font-size: 14px;
  line-height: 1.8;
}
.principal-mailbox-again {
  margin-top: 22px;
  padding: 9px 20px;
  border: 1px solid #bfd3e9;
  border-radius: 999px;
  background: var(--white);
  color: var(--blue);
  font-family: inherit;
  font-size: 14px;
  cursor: pointer;
  transition: border-color 0.18s ease, background-color 0.18s ease;
}
.principal-mailbox-again:hover { border-color: var(--blue); background: var(--blue-light); }

/* =========================================================
   响应式
   ========================================================= */
@media (max-width: 1024px) {
  /* 头部空间收窄时保持搜索框与导航同行 */
  .header-inner { gap: 16px; }
  .main-nav a { padding: 8px 10px; font-size: 14px; }
  .nav-search input { width: 110px; }
  .about-banner { height: 420px; }
  .about-banner-inner h1 { font-size: 34px; }
  .about-intro-grid { grid-template-columns: 1fr; gap: 32px; }
  .industry-layout { grid-template-columns: 1fr; gap: 36px; }
  .about-stats-list { grid-template-columns: repeat(2, 1fr); row-gap: 28px; }
  .contact-grid { grid-template-columns: 1fr; gap: 36px; padding: 36px; }
  .principal-mailbox-layout { grid-template-columns: 1fr; }
  .principal-mailbox-intro { padding: 44px 42px 40px; }
  .principal-mailbox-card { padding: 40px 42px 44px; }
}

@media (max-width: 768px) {
  .main-nav { top: 100%; flex-direction: column; align-items: stretch; gap: 0; }
  .main-nav ul { justify-content: flex-start; }
  .main-nav.open { max-height: 560px; }
  .nav-search { width: calc(100% - 32px); margin: 0 16px 14px; }
  .nav-search input { flex: 1; width: auto; }
  .service-bento { grid-template-columns: 1fr; }
  .service-card-light img { height: 280px; }
  .service-card-feature img { height: 320px; }
  .about-banner { height: 320px; }
  .about-banner-inner h1 { font-size: 27px; letter-spacing: 1px; }
  .about-banner-inner p { font-size: 15px; }
  .about-tab-btns { margin-top: 36px; }
  .about-tabs > .tab-panel .section:first-child { padding-top: 40px; }
  .about-tabs > .tab-panel .section:last-child { padding-bottom: 56px; }
  .about-intro-sec .section-head { margin-bottom: 30px; }
  .about-intro-grid { gap: 24px; }
  .about-intro-body h3 { margin-bottom: 12px; font-size: 20px; }
  .about-intro-body p.type-body {
    font-size: 15px;
    line-height: 1.75;
    text-align: left;
  }
  .about-stats-item strong { font-size: 26px; }
  .about-stats { margin-top: 40px; }
  .about-stats-list { gap: 12px 16px; }
  .about-stats-item:last-child { grid-column: 1 / -1; }

  /* 手机端：五步流程改为紧凑时间线 */
  .teach-system-sec { padding: 24px 0; }
  .teach-system-sec .section-head { margin-bottom: 18px; }
  .teach-system-sec .section-head h2::after { margin-top: 8px; }
  .teach-flow {
    position: relative;
    flex-direction: column;
    align-items: stretch;
    gap: 0;
    margin-bottom: 12px;
  }
  .teach-flow::before {
    content: "";
    position: absolute;
    top: 16px;
    bottom: 16px;
    left: 15px;
    width: 2px;
    background: #d9e6f8;
  }
  .teach-flow li:not(.teach-flow-arrow) {
    display: flex;
    align-items: center;
    gap: 12px;
    width: 100%;
    max-width: none;
    min-width: 0;
    min-height: 40px;
    padding: 4px 0;
    background: transparent;
    border: 0;
    border-radius: 0;
    box-shadow: none;
    text-align: left;
    font-size: 15px;
  }
  .teach-flow li:not(.teach-flow-arrow):hover {
    box-shadow: none;
    transform: none;
  }
  .teach-flow-num {
    position: relative;
    z-index: 1;
    flex: 0 0 32px;
    width: 32px;
    height: 32px;
    margin: 0;
    display: flex;
    align-items: center;
    justify-content: center;
    border: 2px solid var(--blue);
    border-radius: 50%;
    background: var(--white);
    box-shadow: 0 0 0 4px var(--white);
    font-size: 11px;
    line-height: 1;
  }
  .teach-flow-arrow { display: none; }

  /* 四张说明卡两列换行，避免小屏横向滑动 */
  .about-steps {
    display: grid;
    grid-template-columns: repeat(2, minmax(0, 1fr));
    grid-auto-flow: row;
    gap: 10px;
  }
  .about-steps .step-card {
    min-width: 0;
    padding: 14px 12px;
  }
  .about-steps .step-card::before { transform: scaleX(1); }
  .about-steps .step-num {
    margin-bottom: 4px;
    font-size: 20px;
    line-height: 1;
  }
  .about-steps .step-card h3 { margin-bottom: 8px; }
  .about-steps .check-list li {
    padding-left: 16px;
    font-size: 12px;
    line-height: 1.5;
  }

  .join-grid { grid-template-columns: 1fr; gap: 16px; margin-bottom: 32px; }
  .join-grid .why-card { padding: 22px 18px; }
  .join-grid .card-footer {
    justify-content: stretch;
    margin-top: 14px;
  }
  .join-grid .toggle-btn {
    width: 100%;
    min-height: 44px;
    padding: 10px 18px;
  }
  .join-benefits {
    grid-template-columns: 1fr;
    gap: 0;
    padding: 28px 22px;
  }
  .join-benefits h3 { text-align: center; }
  .join-benefits .check-list { margin: 0 auto; }
  .join-contact {
    width: min(100%, 340px);
    margin: 20px auto 0;
    padding: 24px 20px;
    justify-self: center;
  }
  .join-contact-email {
    font-size: 14px;
  }
  .contact-grid { padding: 28px 22px; }
  .principal-mailbox-layout { border-radius: 14px; }
  .principal-mailbox-intro { padding: 34px 24px 30px; }
  .principal-mailbox-seal {
    width: 54px;
    height: 54px;
    margin-bottom: 22px;
  }
  .principal-mailbox-seal svg { width: 29px; height: 29px; }
  .principal-mailbox-intro h2 { font-size: 28px; }
  .principal-mailbox-points { margin-top: 23px; }
  .principal-mailbox-privacy { margin-top: 23px; }
  .principal-mailbox-card { padding: 30px 22px 34px; }
  .principal-mailbox-card-head {
    gap: 12px;
    margin-bottom: 22px;
  }
  .principal-mailbox-card-head h3 { font-size: 20px; }
  .principal-mailbox-form { gap: 16px; }
}

@media (max-width: 480px) {
  .about-banner { height: 260px; }
  .about-banner-inner h1 { font-size: 22px; }
  .industry-grid {
    grid-template-columns: repeat(auto-fit, minmax(128px, 1fr));
    gap: 10px;
  }
  .join-grid .why-card { padding: 20px 16px; }
  .join-benefits { padding: 24px 18px; }
  .contact-qr { gap: 20px; }
  .principal-mailbox-intro h2 { font-size: 25px; }
  .principal-mailbox-lead { font-size: 14px; }
  .principal-mailbox-card-head { flex-direction: column; gap: 5px; }
  .principal-mailbox-required-note { padding-top: 0; }
  .principal-mailbox-field > textarea { min-height: 170px; }
}

/* ---------- 加入我们（展开效果） ---------- */
  /* ============ 卡片 ============ */
  .why-card{
    position: relative;          /* 给悬浮按钮留定位参照 */
  }

  /* ============ 折叠区 ============ */
  .job-content{
    position: relative;
    overflow: hidden;
    max-height: 160px;           /* ★ 收起时显示的高度，按需调整 */
    transition: max-height .35s ease;
  }
  .job-content.expanded{
    max-height: none;
  }

  /* 底部渐隐遮罩 */
  .job-content::after{
    content: "";
    position: absolute;
    left: 0;
    right: 0;
    bottom: 0;
    height: 56px;
    background: linear-gradient(to bottom, rgba(255,255,255,0), #fff);
    pointer-events: none;
    opacity: 1;
    transition: opacity .3s;
  }
  .job-content.expanded::after{
    opacity: 0;
  }

  .job-content p{
    margin: 0 0 10px;
    line-height: 1.8;
  }
  .job-content p:last-child{
    margin-bottom: 0;
  }

  /* ============ 按钮行：靠右对齐 ============ */
  .card-footer{
    display: flex;
    justify-content: flex-end;   /* ★ 按钮靠右 */
    margin-top: 12px;
  }

  /* ============ 按钮样式 ============ */
  .toggle-btn{
    display: inline-block;
    padding: 6px 18px;
    border: 1px solid #1e6fd9;
    border-radius: 20px;
    background: transparent;
    color: #1e6fd9;
    font-size: 14px;
    line-height: 1.4;
    cursor: pointer;
    transition: background .25s, color .25s;
  }
  .toggle-btn:hover{
    background: #1e6fd9;
    color: #fff;
  }
  .toggle-btn:focus-visible {
    outline: 3px solid rgba(30, 111, 217, 0.35);
    outline-offset: 3px;
  }