:root {
  --red: #c60012;
  --dark: #101624;
  --soft: #f3f3f3;
  --text: #202020;
  --muted: #6f7379;
  --container: 1200px
}

* {
  box-sizing: border-box
}

html {
  scroll-behavior: smooth
}

body {
  margin: 0;
  color: var(--text);
  font-family: "Microsoft YaHei", "PingFang SC", Arial, sans-serif;
  background: #fff
}

a {
  color: inherit;
  text-decoration: none
}

.container {
  width: min(var(--container), calc(100% - 48px));
  margin-inline: auto
}

.site-header {
  height: 130px;
  background: #fff;
  position: relative;
  z-index: 20
}

.site-header--overlay {
  position: absolute;
  inset: 0 0 auto;
  background: transparent;
  color: #fff
}

.nav-wrap {
  width: calc(100% - 310px);
  height: 100%;
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin: 0 auto;
}

.brand {
  display: flex;
  align-items: center;
  gap: 15px;
  line-height: 1;
}

.brand .logo-image {
  object-fit: cover;
}

.brand .logo-text {
  font-size: 36px;
  font-weight: 600;
}

.brand-mark {
  display: grid;
  place-items: center;
  width: 36px;
  height: 40px;
  color: #fff;
  background: var(--red);
  font: 900 23px Arial;
  border-radius: 2px
}

.main-nav {
  display: flex;
  align-items: center;
  gap: 80px;
}

.main-nav a {
  height: 100%;
  display: grid;
  place-items: center;
  font-size: 22px;
  position: relative
}

.main-nav a::after {
  content: "";
  position: absolute;
  left: -20px;
  right: -20px;
  bottom: -32px;
  height: 8px;
  background: var(--red);
  transform: scaleX(0);
  transition: .25s
}

.main-nav a:hover::after,
.main-nav a.active::after {
  transform: scaleX(1)
}

.menu-toggle {
  display: none;
  background: none;
  border: 0;
  padding: 10px
}

.menu-toggle span {
  display: block;
  width: 27px;
  height: 2px;
  background: currentColor;
  margin: 6px
}

.inner-hero {
  height: 363px;
  color: #fff;
  background-image: url("../images/about-bg.jpg");
  background-size: 100%;
  background-repeat: no-repeat;
  background-position: top center;
}

.inner-hero>.container {
  height: 100%;
  display: flex;
  flex-direction: column;
  justify-content: center
}

.inner-hero h1 {
  font-size: 56px;
  letter-spacing: 5px;
  margin: 0
}

.inner-hero p {
  font-size: 20px
}

.subnav {
  height: 180px;
  background: #fff;
  border-bottom: 1px solid #ddd
}

.subnav>.container {
  display: flex;
  height: 100%;
  align-items: end;
  gap: 110px
}

.subnav a {
  font-size: 35px;
  padding: 0 40px 43px;
  position: relative
}

.subnav a.active {
  font-weight: 600;
  color: var(--red)
}

.subnav a.active::after {
  content: "";
  position: absolute;
  height: 6px;
  background: var(--red);
  inset: auto 0 0
}

.detail-bg {
  background: #f2f2f2;
  padding: 70px 0 95px;
}

.detail-card {
  background: #fff;
  padding: 65px 50px;
}

.line-title {
  border-left: 8px solid var(--red);
  padding: 5px 0 5px 20px;
  margin: 0 0 72px;
  font-size: 32px
}

.detail-card>h3 {
  font-size: 28px;
  margin-bottom: 10px
}

.en-title {
  font-size: 18px;
  color: #db747d;
  font-weight: 700;
  margin-top: 0
}

.detail-copy {
  margin: 65px 0;
  line-height: 2.5;
  color: #5f6165;
  text-indent: 2em;
  font-size: 20px
}

.office-photo {
  display: flex;
  justify-content: center;
}

.office-photo img {
  object-fit: cover;
}

.value-title {
  margin-top: 130px;
  margin-bottom: 50px
}

.values-text {
  line-height: 2;
  color: #666;
  font-size: 18px;
}

.party-gallery {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 35px
}

.party-photo img {
  object-fit: cover;
}

.footer {
  display: flex;
  align-items: center;
  justify-content: center;
  padding: 20px 0;
  background-color: rgba(20, 26, 50, 1);
}

.footer a,
.item-text {
  font-size: 14px;
  color: rgba(255, 255, 255, 1);
}

.footer a {
  margin: 0 10px;
}

/* =========================
   Mobile responsive styles
   Keep all existing PC styles unchanged
   ========================= */
@media (max-width: 768px) {
  .container {
    width: calc(100% - 32px);
  }

  .site-header {
    height: 72px;
  }

  .nav-wrap {
    width: calc(100% - 32px);
    position: relative;
  }

  .brand {
    gap: 10px;
  }

  .brand .logo-image {
    max-width: 42px;
    height: auto;
  }

  .brand .logo-text {
    font-size: 22px;
  }

  .menu-toggle {
    display: block;
    color: var(--text);
    cursor: pointer;
    position: relative;
    z-index: 22;
  }

  .main-nav {
    display: none;
    position: absolute;
    top: 72px;
    left: -16px;
    right: -16px;
    z-index: 21;
    flex-direction: column;
    align-items: stretch;
    gap: 0;
    padding: 10px 16px 18px;
    background: rgba(255, 255, 255, 0.98);
    box-shadow: 0 12px 24px rgba(0, 0, 0, 0.12);
  }

  .main-nav.is-open,
  .menu-toggle[aria-expanded="true"]+.main-nav {
    display: flex;
  }

  .main-nav a {
    height: auto;
    padding: 14px 8px;
    font-size: 16px;
    text-align: center;
  }

  .main-nav a::after {
    left: 35%;
    right: 35%;
    bottom: 4px;
    height: 3px;
  }

  .inner-hero {
    height: 240px;
    background-size: cover;
    background-position: center;
  }

  .inner-hero>.container {
    justify-content: center;
  }

  .inner-hero h1 {
    font-size: 36px;
    letter-spacing: 3px;
  }

  .inner-hero p {
    margin: 10px 0 0;
    font-size: 15px;
  }

  .subnav {
    height: auto;
  }

  .subnav>.container {
    height: auto;
    align-items: stretch;
    justify-content: center;
    gap: 0;
  }

  .subnav a {
    flex: 1;
    padding: 20px 10px 17px;
    font-size: 20px;
    text-align: center;
  }

  .subnav a.active::after {
    height: 4px;
  }

  .detail-bg {
    padding: 30px 0 50px;
  }

  .detail-card {
    padding: 36px 20px 42px;
  }

  .line-title {
    border-left-width: 5px;
    padding: 3px 0 3px 12px;
    margin-bottom: 38px;
    font-size: 24px;
  }

  .detail-card>h3 {
    font-size: 21px;
    line-height: 1.5;
  }

  .en-title {
    font-size: 12px;
    line-height: 1.7;
    word-break: break-word;
  }

  .detail-copy {
    margin: 34px 0;
    line-height: 2;
    font-size: 15px;
  }

  .office-photo img,
  .party-photo img {
    display: block;
    width: 100%;
    height: auto;
    max-width: 100%;
  }

  .value-title {
    margin-top: 56px;
    margin-bottom: 30px;
  }

  .values-text {
    font-size: 15px;
    line-height: 1.9;
  }

  .party-gallery {
    grid-template-columns: 1fr;
    gap: 18px;
  }

  .footer {
    flex-direction: column;
    gap: 8px;
    padding: 18px 16px;
    text-align: center;
  }

  .footer a {
    margin: 0;
  }
}

@media (max-width: 480px) {
  .inner-hero {
    height: 210px;
  }

  .inner-hero h1 {
    font-size: 30px;
  }

  .inner-hero p {
    font-size: 13px;
  }

  .subnav a {
    font-size: 18px;
    padding-inline: 6px;
  }

  .detail-card {
    padding-inline: 16px;
  }

  .line-title {
    margin-bottom: 30px;
    font-size: 22px;
  }

  .detail-card>h3 {
    font-size: 19px;
  }

  .detail-copy {
    font-size: 14px;
    text-indent: 2em;
  }

  .values-text {
    font-size: 14px;
  }
}