:root {
  color-scheme: light;
  --ink: #0a2028;
  --muted: #536770;
  --paper: #f4f7f2;
  --white: #ffffff;
  --green: #63b55a;
  --green-dark: #2c7b52;
  --line: rgba(10, 32, 40, 0.14);
  --cement: #f2a23a;
  --flow: #2aa8a1;
  --bond: #425ca8;
  --shadow: 0 28px 80px rgba(8, 32, 40, 0.12);
}

* {
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
}

body {
  margin: 0;
  min-width: 320px;
  color: var(--ink);
  background:
    radial-gradient(circle at 86% 8%, rgba(99, 181, 90, 0.16), transparent 27rem),
    linear-gradient(180deg, #fbfdf9 0%, var(--paper) 100%);
  font-family:
    Inter, "Noto Sans TC", "PingFang TC", "Microsoft JhengHei", system-ui, -apple-system, sans-serif;
  line-height: 1.65;
}

a {
  color: inherit;
}

img {
  display: block;
  max-width: 100%;
}

.skip-link {
  position: fixed;
  z-index: 100;
  top: 0.75rem;
  left: 0.75rem;
  padding: 0.65rem 0.9rem;
  color: white;
  background: var(--ink);
  border-radius: 0.5rem;
  transform: translateY(-150%);
}

.skip-link:focus {
  transform: translateY(0);
}

.hub-header {
  position: sticky;
  z-index: 50;
  top: 0;
  display: flex;
  align-items: center;
  justify-content: space-between;
  min-height: 78px;
  padding: 0.85rem clamp(1rem, 4vw, 4.5rem);
  border-bottom: 1px solid rgba(10, 32, 40, 0.09);
  background: rgba(251, 253, 249, 0.9);
  backdrop-filter: blur(18px);
}

.hub-brand {
  display: flex;
  align-items: center;
  gap: 0.8rem;
  text-decoration: none;
}

.hub-brand img {
  width: 7.2rem;
  height: auto;
}

.hub-brand span {
  display: grid;
  line-height: 1.1;
}

.hub-brand strong {
  font-size: 0.88rem;
  letter-spacing: 0.08em;
}

.hub-brand small {
  margin-top: 0.28rem;
  color: var(--muted);
  font-size: 0.68rem;
  letter-spacing: 0.05em;
}

.hub-header nav {
  display: flex;
  align-items: center;
  gap: clamp(0.6rem, 2.5vw, 2.6rem);
}

.hub-header nav a {
  position: relative;
  padding: 0.45rem 0;
  font-size: 0.76rem;
  font-weight: 800;
  letter-spacing: 0.13em;
  text-decoration: none;
}

.hub-header nav a::after {
  position: absolute;
  right: 0;
  bottom: 0.15rem;
  left: 0;
  height: 2px;
  background: var(--green);
  content: "";
  transform: scaleX(0);
  transition: transform 180ms ease;
}

.hub-header nav a:hover::after,
.hub-header nav a:focus-visible::after {
  transform: scaleX(1);
}

.hub-hero,
.category-section,
.how-section {
  width: min(1440px, calc(100% - 2rem));
  margin-inline: auto;
}

.hub-hero {
  display: grid;
  grid-template-columns: minmax(0, 1.02fr) minmax(31rem, 0.98fr);
  gap: clamp(2rem, 6vw, 7rem);
  align-items: center;
  min-height: calc(100svh - 78px);
  padding: clamp(4rem, 8vw, 8.5rem) clamp(0.25rem, 2vw, 2rem);
}

.eyebrow {
  margin: 0 0 1rem;
  color: var(--green-dark);
  font-size: 0.72rem;
  font-weight: 850;
  letter-spacing: 0.2em;
}

.hero-copy h1 {
  max-width: 12ch;
  margin: 0;
  font-size: clamp(3.2rem, 7.1vw, 7rem);
  font-weight: 830;
  letter-spacing: -0.065em;
  line-height: 0.98;
}

.hero-copy h1::after {
  display: block;
  width: 5.5rem;
  height: 0.38rem;
  margin-top: 1.7rem;
  background: linear-gradient(90deg, var(--green), var(--flow));
  border-radius: 999px;
  content: "";
}

.hero-lead {
  max-width: 42rem;
  margin: 1.7rem 0 0;
  color: var(--muted);
  font-size: clamp(1rem, 1.35vw, 1.2rem);
}

.hero-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 0.8rem;
  margin-top: 2rem;
}

.button {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-height: 48px;
  padding: 0.8rem 1.3rem;
  border: 1px solid var(--ink);
  border-radius: 999px;
  font-size: 0.87rem;
  font-weight: 800;
  text-decoration: none;
  transition:
    transform 180ms ease,
    box-shadow 180ms ease,
    background 180ms ease;
}

.button:hover {
  transform: translateY(-2px);
}

.button-primary {
  color: white;
  background: var(--ink);
  box-shadow: 0 12px 30px rgba(10, 32, 40, 0.22);
}

.button-primary:hover {
  box-shadow: 0 18px 38px rgba(10, 32, 40, 0.28);
}

.button-ghost {
  background: transparent;
}

.button-ghost:hover {
  background: white;
}

.source-stamp {
  max-width: 44rem;
  margin: 1.4rem 0 0;
  color: #77878c;
  font-size: 0.72rem;
}

.hero-orbit {
  position: relative;
  min-height: 620px;
  isolation: isolate;
}

.hero-orbit::before,
.hero-orbit::after {
  position: absolute;
  inset: 10% 11%;
  z-index: -1;
  border: 1px solid rgba(10, 32, 40, 0.13);
  border-radius: 50%;
  content: "";
}

.hero-orbit::after {
  inset: 23% 24%;
  border-color: rgba(99, 181, 90, 0.3);
}

.orbit-center {
  position: absolute;
  top: 50%;
  left: 50%;
  display: grid;
  place-items: center;
  width: 15rem;
  aspect-ratio: 1;
  padding: 2rem;
  background: rgba(255, 255, 255, 0.86);
  border: 1px solid rgba(99, 181, 90, 0.26);
  border-radius: 50%;
  box-shadow: var(--shadow);
  transform: translate(-50%, -50%);
  backdrop-filter: blur(10px);
}

.orbit-center img {
  width: 10rem;
}

.orbit-center span {
  margin-top: -2.4rem;
  color: var(--green-dark);
  font-size: 0.66rem;
  font-weight: 850;
  letter-spacing: 0.22em;
}

.orbit-item {
  position: absolute;
  display: grid;
  min-width: 13rem;
  padding: 1.2rem 1.35rem;
  overflow: hidden;
  color: white;
  background: var(--ink);
  border-radius: 1.25rem;
  box-shadow: 0 22px 50px rgba(8, 32, 40, 0.2);
  text-decoration: none;
  transition:
    transform 180ms ease,
    box-shadow 180ms ease;
}

.orbit-item::after {
  position: absolute;
  top: -45%;
  right: -18%;
  width: 8rem;
  aspect-ratio: 1;
  background: rgba(255, 255, 255, 0.1);
  border-radius: 50%;
  content: "";
}

.orbit-item:hover {
  box-shadow: 0 28px 58px rgba(8, 32, 40, 0.28);
  transform: translateY(-5px) rotate(0deg);
}

.orbit-item small {
  opacity: 0.65;
  font-weight: 800;
}

.orbit-item strong {
  margin-top: 1.3rem;
  font-size: 1.2rem;
  letter-spacing: 0.1em;
}

.orbit-item span {
  opacity: 0.8;
  font-size: 0.86rem;
}

.orbit-cement {
  top: 8%;
  left: 6%;
  background: #b7661c;
  transform: rotate(-4deg);
}

.orbit-flow {
  top: 18%;
  right: 1%;
  background: #167e7b;
  transform: rotate(3deg);
}

.orbit-bond {
  right: 12%;
  bottom: 5%;
  background: #324c99;
  transform: rotate(-2deg);
}

.category-section {
  padding: 2rem clamp(0.25rem, 2vw, 2rem) clamp(5rem, 10vw, 10rem);
}

.section-heading {
  max-width: 52rem;
  margin-bottom: 2.2rem;
}

.section-heading h2 {
  margin: 0;
  font-size: clamp(2.15rem, 4vw, 4.4rem);
  letter-spacing: -0.045em;
  line-height: 1.04;
}

.section-heading > p:last-child {
  color: var(--muted);
  font-size: 1.04rem;
}

.category-grid {
  display: grid;
  gap: 1.1rem;
}

.category-card {
  position: relative;
  display: grid;
  grid-template-columns: 5rem minmax(20rem, 0.78fr) minmax(22rem, 1.22fr);
  gap: 2rem;
  align-items: center;
  min-height: 420px;
  padding: clamp(1.5rem, 3.5vw, 3.5rem);
  overflow: hidden;
  background: white;
  border: 1px solid var(--line);
  border-radius: 2rem;
  box-shadow: 0 12px 40px rgba(8, 32, 40, 0.06);
}

.category-card::before {
  position: absolute;
  inset: 0 auto 0 0;
  width: 0.45rem;
  background: var(--accent);
  content: "";
}

.category-cement {
  --accent: var(--cement);
  --wash: #fff2dc;
}

.category-flow {
  --accent: var(--flow);
  --wash: #e3f6f4;
}

.category-bond {
  --accent: var(--bond);
  --wash: #e9edfa;
}

.category-index {
  align-self: start;
  color: var(--accent);
  font-size: 0.78rem;
  font-weight: 900;
  letter-spacing: 0.18em;
}

.category-copy {
  position: relative;
  z-index: 2;
}

.category-tag {
  margin: 0 0 0.5rem;
  color: var(--accent);
  font-size: 0.68rem;
  font-weight: 900;
  letter-spacing: 0.16em;
}

.category-copy h3 {
  margin: 0;
  font-size: clamp(2rem, 3.5vw, 3.6rem);
  letter-spacing: -0.05em;
  line-height: 1.04;
}

.category-copy h3 span {
  display: block;
  margin-top: 0.35rem;
  color: var(--accent);
  font-size: 0.42em;
  letter-spacing: 0.12em;
}

.category-copy > p:not(.category-tag) {
  max-width: 40rem;
  color: var(--muted);
}

.category-copy ul {
  display: grid;
  gap: 0.3rem;
  margin: 1rem 0 1.5rem;
  padding: 0;
  list-style: none;
}

.category-copy li::before {
  display: inline-block;
  width: 0.48rem;
  height: 0.48rem;
  margin-right: 0.65rem;
  background: var(--accent);
  border-radius: 50%;
  content: "";
  vertical-align: 0.08em;
}

.category-link {
  display: inline-flex;
  align-items: center;
  gap: 0.7rem;
  color: var(--accent);
  font-size: 0.9rem;
  font-weight: 850;
  text-decoration: none;
}

.category-link span {
  font-size: 1.3rem;
  transition: transform 180ms ease;
}

.category-link:hover span {
  transform: translateX(0.25rem);
}

.category-visual {
  position: relative;
  display: flex;
  align-items: flex-end;
  justify-content: center;
  min-height: 340px;
  padding: 2rem;
  background:
    radial-gradient(circle at 50% 50%, white 0 19%, transparent 45%),
    var(--wash);
  border-radius: 1.6rem;
}

.category-visual::after {
  position: absolute;
  right: 9%;
  bottom: 9%;
  left: 9%;
  height: 1.1rem;
  background: rgba(10, 32, 40, 0.16);
  border-radius: 50%;
  filter: blur(13px);
  content: "";
}

.category-visual img {
  position: relative;
  z-index: 1;
  object-fit: contain;
}

.cement-visual img {
  width: 48%;
  max-height: 285px;
}

.cement-visual img + img {
  margin-left: -8%;
}

.flow-visual img {
  width: 32%;
  max-height: 300px;
}

.flow-visual img:nth-child(2) {
  z-index: 2;
  width: 38%;
  margin-inline: -11%;
  transform: translateY(-1rem);
}

.bond-visual img {
  width: 52%;
  max-height: 290px;
}

.bond-visual img + img {
  width: 42%;
  margin-left: -9%;
}

.how-section {
  padding: clamp(4rem, 8vw, 8rem) clamp(1.25rem, 4vw, 4rem);
  color: white;
  background: var(--ink);
  border-radius: 2.5rem 2.5rem 0 0;
}

.how-section .eyebrow {
  color: #8edc78;
}

.section-heading.compact {
  margin-bottom: 3rem;
}

.how-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 1px;
  background: rgba(255, 255, 255, 0.15);
  border: 1px solid rgba(255, 255, 255, 0.15);
}

.how-grid article {
  min-height: 240px;
  padding: clamp(1.5rem, 3vw, 3rem);
  background: var(--ink);
}

.how-number {
  color: #8edc78;
  font-size: 0.72rem;
  font-weight: 900;
  letter-spacing: 0.16em;
}

.how-grid h3 {
  margin: 2rem 0 0.6rem;
  font-size: 1.7rem;
}

.how-grid p {
  margin: 0;
  color: rgba(255, 255, 255, 0.7);
}

.hub-footer {
  display: grid;
  place-items: center;
  padding: 3rem 1rem;
  color: #6f7f84;
  background: #eaf0e8;
  text-align: center;
}

.hub-footer img {
  width: 7rem;
}

.hub-footer p {
  margin: 0.7rem 0 0;
  font-size: 0.78rem;
}

.hub-footer .footer-note {
  max-width: 42rem;
  margin-top: 0.3rem;
  font-size: 0.7rem;
}

@media (max-width: 1050px) {
  .hub-hero {
    grid-template-columns: 1fr;
  }

  .hero-orbit {
    width: min(100%, 42rem);
    min-height: 560px;
    margin-inline: auto;
  }

  .category-card {
    grid-template-columns: 3rem 1fr;
  }

  .category-visual {
    grid-column: 1 / -1;
  }
}

@media (max-width: 720px) {
  .hub-header {
    min-height: 68px;
    padding-inline: 1rem;
  }

  .hub-brand img {
    width: 6rem;
  }

  .hub-brand span {
    display: none;
  }

  .hub-header nav {
    gap: 0.8rem;
  }

  .hub-header nav a {
    font-size: 0.62rem;
  }

  .hub-hero {
    min-height: auto;
    padding-block: 4rem 2rem;
  }

  .hero-copy h1 {
    font-size: clamp(3rem, 14vw, 4.8rem);
  }

  .hero-orbit {
    min-height: 490px;
  }

  .orbit-center {
    width: 11rem;
    padding: 1.4rem;
  }

  .orbit-center img {
    width: 7.8rem;
  }

  .orbit-center span {
    margin-top: -1.8rem;
    font-size: 0.55rem;
  }

  .orbit-item {
    min-width: 10.5rem;
    padding: 1rem;
  }

  .orbit-item strong {
    margin-top: 0.8rem;
    font-size: 0.95rem;
  }

  .orbit-cement {
    left: 0;
  }

  .orbit-flow {
    right: 0;
  }

  .orbit-bond {
    right: 3%;
  }

  .category-card {
    grid-template-columns: 1fr;
    gap: 1rem;
    min-height: 0;
    padding: 1.5rem;
    border-radius: 1.4rem;
  }

  .category-index {
    display: none;
  }

  .category-visual {
    grid-column: auto;
    min-height: 260px;
    padding: 1rem;
  }

  .category-copy h3 {
    font-size: 2.45rem;
  }

  .how-section {
    width: 100%;
    border-radius: 2rem 2rem 0 0;
  }

  .how-grid {
    grid-template-columns: 1fr;
  }
}

@media (prefers-reduced-motion: reduce) {
  *,
  *::before,
  *::after {
    scroll-behavior: auto !important;
    transition: none !important;
  }
}