:root {
  font-family: system-ui, -apple-system, "Segoe UI", "Noto Sans TC", sans-serif;
  color: #17324d;
  background: #f5f8fb;
}

* {
  box-sizing: border-box;
}

body {
  min-width: 320px;
  min-height: 100vh;
  margin: 0;
  line-height: 1.7;
}

a {
  color: #155e75;
}

a:focus-visible,
button:focus-visible,
input:focus-visible,
textarea:focus-visible {
  outline: 3px solid #f1ab2c;
  outline-offset: 3px;
}

.site-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1rem;
  width: min(100% - 2rem, 920px);
  margin: 1rem auto 0;
  padding: .75rem 0;
}

.brand {
  color: #17324d;
  font-weight: 800;
  text-decoration: none;
  white-space: nowrap;
}

.site-header nav {
  display: flex;
  flex-wrap: wrap;
  gap: .7rem 1rem;
}

.site-header nav a[aria-current="page"] {
  font-weight: 800;
  text-decoration-thickness: 3px;
  text-underline-offset: .25rem;
}

.page-shell {
  width: min(100% - 2rem, 760px);
  margin: 2rem auto;
  padding: clamp(1.25rem, 4vw, 2rem);
  border: 1px solid #cbd8e4;
  border-radius: 20px;
  background: #fff;
}

.eyebrow {
  margin: 0 0 .5rem;
  color: #176b87;
  font-weight: 800;
  letter-spacing: .06em;
}

h1,
h2 {
  line-height: 1.25;
}

h1 {
  margin: 0;
}

.page-description {
  margin: .75rem 0 0;
  color: #52657d;
}

.content-section {
  margin-top: 2rem;
}

.content-section h2 {
  margin: 0 0 .7rem;
}

.content-section p {
  margin: 0;
}

.link-grid,
.service-grid {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 1rem;
}

.link-card,
.service-card {
  display: flex;
  flex-direction: column;
  gap: .45rem;
  min-width: 0;
  padding: 1rem;
  border: 1px solid #d8e0ea;
  border-radius: 14px;
  background: #fbfdff;
  text-decoration: none;
}

.link-card span,
.service-card p {
  color: #52657d;
}

.service-card strong {
  color: #17643d;
}

.button-link,
button {
  display: inline-block;
  margin-top: 1.25rem;
  padding: .65rem .9rem;
  border: 0;
  border-radius: 9px;
  background: #176b87;
  color: #fff;
  font: inherit;
  font-weight: 700;
  text-decoration: none;
  cursor: pointer;
}

.button-link:hover,
button:hover {
  background: #0d4053;
}

.contact-form {
  display: grid;
  gap: 1rem;
  margin-top: 1.5rem;
}

.form-field {
  display: grid;
  gap: .35rem;
}

label {
  font-weight: 700;
}

input,
textarea {
  width: 100%;
  padding: .65rem .75rem;
  border: 1px solid #aebdca;
  border-radius: 8px;
  background: #fff;
  color: inherit;
  font: inherit;
}

textarea {
  resize: vertical;
}

.contact-form button {
  justify-self: start;
  margin-top: 0;
}

.status {
  min-height: 2rem;
  margin: 0;
  color: #52657d;
}

.status[data-state="success"] {
  color: #17643d;
}

.status[data-state="error"] {
  color: #a13d2d;
}

.lesson-note {
  margin-top: 1.5rem;
  padding: 1rem;
  border: 1px solid #c8e4eb;
  border-radius: 14px;
  background: #f2fafb;
}

.site-footer {
  padding: 2rem 1rem;
  border-top: 1px solid #d8e0ea;
  color: #52657d;
  text-align: center;
}

.site-footer p {
  max-width: 760px;
  margin: 0 auto;
}

@media (max-width: 680px) {
  .site-header {
    align-items: flex-start;
    flex-direction: column;
  }

  .link-grid,
  .service-grid {
    grid-template-columns: 1fr;
  }
}

@media (max-width: 420px) {
  .site-header,
  .page-shell {
    width: min(100% - 1.25rem, 760px);
  }

  .site-header nav {
    gap: .5rem .75rem;
  }
}