:root {
  color-scheme: light;
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "Microsoft YaHei UI", Arial, sans-serif;
  color: #20252b;
  background: #f6f7f8;
  font-synthesis: none;
}

* { box-sizing: border-box; }
body { margin: 0; min-width: 320px; background: #f6f7f8; }
a { color: inherit; text-decoration: none; }

.topbar {
  height: 66px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 0 max(24px, calc((100vw - 1040px) / 2));
  border-bottom: 1px solid #dfe3e8;
  background: #fff;
}

.brand { font-size: 15px; font-weight: 700; }
.back { color: #626d78; font-size: 13px; }
.back:hover { color: #20252b; }

.download-page {
  width: min(1040px, calc(100% - 40px));
  min-height: calc(100vh - 156px);
  margin: 0 auto;
  padding: 52px 0 64px;
}

.product-intro {
  display: grid;
  grid-template-columns: minmax(280px, .72fr) minmax(480px, 1.28fr);
  align-items: center;
  gap: 58px;
}

.product-copy > p { margin: 0 0 13px; color: #5275a6; font-size: 11px; font-weight: 750; }
.product-copy h1 { max-width: 360px; margin: 0; font-size: 40px; font-weight: 720; line-height: 1.12; }
.product-copy dl { display: grid; grid-template-columns: repeat(3, auto); justify-content: start; gap: 28px; margin: 28px 0; }
.product-copy dl > div { display: grid; gap: 5px; }
.product-copy dt { color: #7a8490; font-size: 11px; }
.product-copy dd { margin: 0; font-size: 13px; font-weight: 650; }
.product-copy > a { display: inline-flex; gap: 7px; align-items: center; padding-bottom: 4px; border-bottom: 1px solid #9ca6b0; color: #4e5965; font-size: 12px; }
.product-copy > a:hover { color: #20252b; border-color: #20252b; }

.product-media { min-width: 0; }
.preview-image { width: 100%; height: 310px; display: block; object-fit: cover; object-position: center 47%; border-radius: 6px; background: #dfe3e8; }
.preview-thumbs { display: grid; grid-template-columns: repeat(4, 1fr); gap: 8px; margin-top: 9px; }
.preview-thumbs button { height: 58px; overflow: hidden; padding: 0; border: 2px solid transparent; border-radius: 4px; background: #e4e7ea; cursor: pointer; opacity: .7; }
.preview-thumbs button:hover { opacity: 1; }
.preview-thumbs button.active { border-color: #5275a6; opacity: 1; }
.preview-thumbs img { width: 100%; height: 100%; display: block; object-fit: cover; }

.download-panel {
  margin-top: 42px;
  overflow: hidden;
  border: 1px solid #d8dde3;
  border-radius: 7px;
  background: #fff;
}

.recommended-heading {
  min-height: 86px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 28px;
  padding: 20px 24px;
  border-bottom: 1px solid #e3e7eb;
  color: #20252b;
  background: #fff;
}
.recommended-heading > div { min-width: 0; }
.recommended-heading h2 { margin: 0; font-size: 17px; line-height: 1.3; }
.recommended-heading h2 span {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-height: 22px;
  margin-left: 6px;
  padding: 0 8px;
  border-radius: 999px;
  color: #315f9b;
  background: #edf3fa;
  font-size: 11px;
  vertical-align: 2px;
}
.recommended-heading p { margin: 7px 0 0; color: #66717c; font-size: 12px; line-height: 1.55; }
.recommended-heading > strong { flex: 0 0 auto; color: #727d88; font-size: 12px; }

.download-steps { margin: 0; padding: 0; list-style: none; }
.download-steps li {
  min-height: 78px;
  display: grid;
  grid-template-columns: 22px minmax(0, 1fr) minmax(170px, 190px);
  align-items: center;
  gap: 14px;
  padding: 14px 24px;
  border-bottom: 1px solid #e3e7eb;
}
.step-number {
  color: #7a8490;
  font-size: 13px;
  font-weight: 650;
}
.step-number::after { content: "."; }
.step-copy { min-width: 0; display: grid; gap: 5px; }
.step-copy strong { font-size: 14px; }
.step-copy span { color: #727d88; font-size: 12px; }
.step-download {
  min-height: 44px;
  display: grid;
  place-content: center;
  gap: 2px;
  padding: 6px 14px;
  border-radius: 5px;
  color: #fff;
  background: #315f9b;
  font-size: 13px;
  font-weight: 650;
  text-align: center;
}
.step-download:hover { background: #244f87; }
.step-download:active { background: #1d4374; }
.step-download:focus-visible { outline: 3px solid rgba(49, 95, 155, .3); outline-offset: 3px; }
.step-download small { color: rgba(255, 255, 255, .82); font-size: 10px; font-weight: 550; }

.ordinary-download-tip {
  display: grid;
  grid-template-columns: 260px 1fr;
  align-items: center;
  gap: 18px;
  padding: 15px 24px;
  color: #46525e;
  background: #f6f7f8;
}
.ordinary-download-tip strong { color: #315f9b; font-size: 13px; }
.ordinary-download-tip span { font-size: 12px; line-height: 1.55; }

.install-note { display: grid; grid-template-columns: 112px 1fr; gap: 18px; padding: 17px 24px; background: #fff; }
.install-note strong { color: #303944; font-size: 13px; }
.install-note span { color: #59646f; font-size: 12px; line-height: 1.65; }
.install-note code { font-family: Consolas, monospace; font-size: 11px; }

.other-routes { border-top: 1px solid #e3e7eb; background: #f8f9fb; }
.other-routes summary {
  min-height: 52px;
  display: flex;
  align-items: center;
  gap: 12px;
  padding: 0 24px;
  color: #59646f;
  cursor: pointer;
  font-size: 13px;
  font-weight: 650;
}
.other-routes summary:hover { color: #303944; background: #f2f4f7; }
.other-routes summary:focus-visible { outline: 3px solid rgba(49, 95, 155, .26); outline-offset: -3px; }
.other-routes summary small { color: #7a8490; font-size: 11px; font-weight: 500; }
.download-file {
  min-height: 88px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 28px;
  padding: 18px 24px;
  border-top: 1px solid #e3e7eb;
  background: #fff;
}
.download-file > div:first-child { min-width: 0; display: grid; gap: 6px; }
.download-file strong { overflow: hidden; text-overflow: ellipsis; font-size: 14px; white-space: nowrap; }
.download-file span { color: #727d88; font-size: 12px; }
.download-actions { display: flex; align-items: center; gap: 9px; }
.primary-download,
.backup-download {
  min-height: 42px;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  padding: 0 18px;
  border: 1px solid #c8ced5;
  border-radius: 5px;
  color: #4c5864;
  background: #fff;
  font-size: 12px;
  font-weight: 650;
}
.primary-download:hover,
.backup-download:hover { border-color: #9ba7b4; background: #f3f5f7; }
.primary-download:focus-visible,
.backup-download:focus-visible { outline: 3px solid rgba(49, 95, 155, .26); outline-offset: 2px; }

.checksums { margin-top: 17px; color: #69747f; font-size: 12px; }
.checksums summary { width: fit-content; cursor: pointer; user-select: none; }
.checksums dl { margin: 14px 0 0; padding: 16px 19px; border: 1px solid #d8dde3; border-radius: 6px; background: #fff; }
.checksums dl > div { display: grid; grid-template-columns: 98px minmax(0, 1fr); gap: 16px; padding: 6px 0; }
.checksums dt { font-weight: 650; }
.checksums dd { min-width: 0; margin: 0; overflow-wrap: anywhere; font-family: Consolas, monospace; font-size: 11px; }

footer {
  width: min(1040px, calc(100% - 40px));
  min-height: 90px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin: 0 auto;
  border-top: 1px solid #dfe3e8;
  color: #7a8490;
  font-size: 11px;
}

@media (max-width: 760px) {
  .topbar { height: 62px; padding: 0 18px; }
  .download-page { width: calc(100% - 28px); padding: 30px 0 46px; }
  .product-intro { grid-template-columns: 1fr; gap: 25px; }
  .product-copy h1 { max-width: none; font-size: 31px; }
  .product-copy dl { margin: 20px 0; gap: 24px; }
  .product-copy > a { display: none; }
  .preview-image { height: auto; aspect-ratio: 16 / 9; }
  .preview-thumbs button { height: 44px; }
  .download-panel { margin-top: 28px; }
  .recommended-heading { min-height: 0; align-items: flex-start; flex-direction: column; gap: 11px; padding: 19px; }
  .recommended-heading h2 { font-size: 17px; }
  .recommended-heading h2 span { margin-left: 4px; vertical-align: 2px; }
  .recommended-heading > strong { font-size: 12px; }
  .download-steps li { grid-template-columns: 20px minmax(0, 1fr); gap: 10px; padding: 15px 19px 18px; }
  .step-download { grid-column: 1 / -1; min-height: 46px; }
  .ordinary-download-tip { grid-template-columns: 1fr; gap: 4px; padding: 15px 19px; }
  .install-note { grid-template-columns: 1fr; gap: 6px; padding: 18px 20px 21px; }
  .other-routes summary { align-items: flex-start; flex-direction: column; justify-content: center; gap: 3px; padding: 12px 20px; }
  .download-file { min-height: 0; align-items: stretch; flex-direction: column; gap: 17px; padding: 19px 20px; }
  .download-actions { display: grid; grid-template-columns: 1fr 1fr; }
  .primary-download,
  .backup-download { width: 100%; padding: 0 12px; }
  .checksums dl > div { grid-template-columns: 1fr; gap: 5px; }
  footer { width: calc(100% - 28px); }
}

@media (prefers-reduced-motion: reduce) {
  *, *::before, *::after { transition-duration: .01ms !important; }
}

/* 教学管理说明与留言验证弹窗 */
.cs-modal-backdrop {
  position: fixed;
  top: 0;
  left: 0;
  width: 100vw;
  height: 100vh;
  background: rgba(15, 23, 42, 0.65);
  backdrop-filter: blur(4px);
  z-index: 9999;
  display: flex;
  align-items: center;
  justify-content: center;
  padding: 20px;
}

.cs-modal-card {
  background: #ffffff;
  border-radius: 6px;
  box-shadow: 0 12px 36px rgba(0, 0, 0, 0.22);
  width: min(520px, 100%);
  border: 1px solid #dfe3e8;
  overflow: hidden;
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "Microsoft YaHei UI", Arial, sans-serif;
}

.cs-modal-header {
  padding: 16px 20px;
  background: #f8f9fa;
  border-bottom: 1px solid #dfe3e8;
  font-size: 15px;
  font-weight: 700;
  color: #20252b;
}

.cs-modal-body {
  padding: 18px 20px;
  font-size: 13.5px;
  line-height: 1.65;
  color: #3c444e;
}

.cs-modal-body p {
  margin: 0 0 12px;
}

.cs-modal-body p:last-child {
  margin-bottom: 0;
}

.cs-modal-body strong {
  color: #1a1f24;
}

.cs-modal-footer {
  padding: 14px 20px;
  display: flex;
  justify-content: flex-end;
  gap: 12px;
  background: #fafbfc;
  border-top: 1px solid #f0f2f5;
}

.cs-modal-btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  padding: 8px 18px;
  font-size: 13px;
  font-weight: 600;
  border-radius: 4px;
  text-decoration: none;
  cursor: pointer;
  border: none;
}

.cs-modal-btn.primary {
  background: #23497d;
  color: #ffffff;
}

.cs-modal-btn.primary:hover {
  background: #19365e;
}

.cs-notice-banner {
  background: #fffbe6;
  border: 1px solid #ffe58f;
  border-radius: 4px;
  padding: 11px 16px;
  font-size: 13px;
  color: #594300;
  margin-bottom: 24px;
  line-height: 1.6;
}

.cs-notice-banner a {
  color: #1677ff;
  text-decoration: underline;
  margin-left: 6px;
}