:root {
  --text: #1f2937;
  --muted: #4b5563;
  --accent: #0f766e;
  --accent-2: #1d4ed8;
  --border: #dbe2ea;
  --shadow: 0 12px 28px rgba(15, 23, 42, 0.12);
}

* {
  box-sizing: border-box;
}

body {
  margin: 0;
  font-family: "PingFang SC", "Noto Sans SC", "Microsoft YaHei", Arial, sans-serif;
  color: var(--text);
  line-height: 1.75;
  position: relative;
  min-height: 100vh;
}

body::before {
  content: "";
  position: fixed;
  inset: 0;
  z-index: -2;
  background-size: cover;
  background-position: center;
}

body::after {
  content: "";
  position: fixed;
  inset: 0;
  z-index: -1;
  pointer-events: none;
}

body.page-home::before {
  background-image: url("WechatIMG268.png");
}

body.page-home::after {
  background: linear-gradient(180deg, rgba(248, 251, 255, 0.72), rgba(248, 251, 255, 0.85));
}

body.page-sub::before {
  background-image: url("WechatIMG269.jpeg");
}

body.page-sub::after {
  background: linear-gradient(180deg, rgba(251, 252, 254, 0.82), rgba(251, 252, 254, 0.9));
}

.container {
  max-width: 1120px;
  margin: 0 auto;
  padding: 0 20px;
}

.top-nav-wrap {
  position: sticky;
  top: 0;
  z-index: 60;
  padding: 10px 0 12px;
  background: linear-gradient(180deg, rgba(255, 255, 255, 0.92), rgba(255, 255, 255, 0.55));
  backdrop-filter: blur(12px);
}

.top-nav {
  display: flex;
  gap: 10px;
  flex-wrap: wrap;
  padding: 10px 12px;
  border-radius: 999px;
  border: 1px solid var(--border);
  background: rgba(255, 255, 255, 0.86);
  box-shadow: 0 12px 26px rgba(15, 23, 42, 0.12);
}

.top-nav a {
  text-decoration: none;
  color: #1e3a8a;
  background: #ffffff;
  border: 1px solid var(--border);
  border-radius: 999px;
  font-size: 14px;
  padding: 7px 13px;
  transition: all 0.18s ease;
}

.top-nav a:hover {
  transform: translateY(-1px);
  border-color: #c7d2fe;
  box-shadow: 0 6px 16px rgba(37, 99, 235, 0.16);
}

.top-nav a.active {
  background: var(--accent-2);
  color: #fff;
  border-color: var(--accent-2);
  box-shadow: 0 8px 16px rgba(37, 99, 235, 0.28);
}

header.hero {
  padding: 34px 0 14px;
}

h1 {
  margin: 0 0 8px;
  font-size: 36px;
  letter-spacing: 0.4px;
}

h2 {
  margin: 0 0 12px;
  font-size: 30px;
  border-left: 6px solid var(--accent);
  padding-left: 12px;
}

h3 {
  margin: 0 0 8px;
  font-size: 20px;
}

p {
  margin: 10px 0;
}

.subtitle {
  color: var(--muted);
  font-weight: 500;
}

main {
  padding: 8px 0 32px;
}

.home-flow {
  max-width: 920px;
}

.home-flow h3 {
  margin-top: 24px;
  font-size: 21px;
}

.home-flow p {
  margin: 8px 0 10px;
}

.jump-link {
  color: #1d4ed8;
  text-decoration: none;
  font-weight: 600;
  border-bottom: 1px solid rgba(29, 78, 216, 0.35);
  padding-bottom: 2px;
}

.jump-link:hover {
  color: #1e40af;
  border-bottom-color: rgba(30, 64, 175, 0.65);
}

.card {
  background: linear-gradient(180deg, rgba(255, 255, 255, 0.92), rgba(255, 255, 255, 0.94));
  border: 1px solid var(--border);
  border-radius: 16px;
  padding: 18px;
  box-shadow: var(--shadow);
}

.grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(240px, 1fr));
  gap: 16px;
}

.hero-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
  gap: 16px;
}

.media-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
  gap: 14px;
}

.img-frame {
  border-radius: 14px;
  overflow: hidden;
  border: 1px solid var(--border);
  background: #fff;
  box-shadow: 0 10px 24px rgba(15, 23, 42, 0.08);
  aspect-ratio: 4 / 3;
}

.img-frame img,
.img-frame video {
  width: 100%;
  height: 100%;
  object-fit: cover;
  display: block;
}

.btn {
  display: inline-flex;
  text-decoration: none;
  border-radius: 999px;
  border: 1px solid transparent;
  padding: 8px 14px;
  background: var(--accent-2);
  color: #fff;
  font-size: 14px;
}

.btn-outline {
  background: #fff;
  color: var(--accent-2);
  border-color: var(--border);
}

.list-tight {
  margin: 0;
  padding-left: 18px;
}

.list-tight li {
  margin: 4px 0;
}

.muted {
  color: var(--muted);
}

table {
  width: 100%;
  border-collapse: collapse;
  border: 1px solid var(--border);
  border-radius: 12px;
  overflow: hidden;
  background: #fff;
}

th,
td {
  padding: 10px 12px;
  border-bottom: 1px solid var(--border);
  text-align: left;
}

th {
  background: #f3f4f6;
}

details {
  margin-top: 10px;
  padding: 10px 12px;
  background: #fff;
  border-radius: 12px;
  border: 1px solid var(--border);
}

summary {
  cursor: pointer;
  font-weight: 600;
}

.form-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
  gap: 12px;
}

label {
  font-size: 14px;
  color: var(--muted);
}

input,
select,
textarea,
button {
  width: 100%;
  border: 1px solid var(--border);
  border-radius: 10px;
  padding: 10px 12px;
  font-size: 14px;
  font-family: inherit;
}

button {
  background: var(--accent);
  color: #fff;
  border: none;
  cursor: pointer;
}

.form-actions {
  display: flex;
  gap: 12px;
  align-items: center;
  flex-wrap: wrap;
}

.form-message {
  font-size: 14px;
  padding: 8px 12px;
  border-radius: 10px;
  border: 1px solid transparent;
}

.form-message.error {
  color: #b91c1c;
  background: #fef2f2;
  border-color: #fecaca;
}

.form-message.success {
  color: #065f46;
  background: #ecfdf3;
  border-color: #bbf7d0;
}

footer {
  padding: 16px 0 30px;
  color: var(--muted);
}

.footprint-intro {
  margin-bottom: 16px;
}

.section-card {
  margin-top: 16px;
}

.section-head {
  display: flex;
  gap: 16px;
  justify-content: space-between;
  align-items: flex-start;
  flex-wrap: wrap;
  margin-bottom: 14px;
}

.tag-row,
.mate-meta {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
}

.tag-chip {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  padding: 6px 12px;
  border-radius: 999px;
  background: rgba(29, 78, 216, 0.08);
  border: 1px solid rgba(29, 78, 216, 0.14);
  color: #1d4ed8;
  font-size: 13px;
  line-height: 1;
}

.mate-layout {
  display: grid;
  grid-template-columns: minmax(0, 1.7fr) minmax(260px, 0.9fr);
  gap: 18px;
}

.mate-posts {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
  gap: 14px;
}

.mate-card {
  padding: 14px;
  border-radius: 14px;
  border: 1px solid var(--border);
  background: linear-gradient(180deg, #ffffff, #f8fbff);
  box-shadow: 0 10px 22px rgba(15, 23, 42, 0.08);
}

.mate-card p {
  margin: 12px 0 0;
}

.mate-gallery {
  display: grid;
  gap: 14px;
}

.img-frame.tall {
  aspect-ratio: 3 / 4;
}

.volunteer-grid {
  align-items: start;
}

@media (max-width: 900px) {
  .mate-layout {
    grid-template-columns: 1fr;
  }
}