* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}

body {
  font-family: "Microsoft YaHei", "PingFang SC", Arial, sans-serif;
  background: linear-gradient(180deg, #f5f8fc 0%, #eef3f9 100%);
  color: #1f2d3d;
  line-height: 1.6;
}

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

header {
  background: linear-gradient(135deg, #2e8dec, #4ca4e7);
  color: white;
  padding: 48px 20px 28px;
  text-align: center;
  box-shadow: 0 8px 20px rgba(0, 0, 0, 0.12);
}

header h1 {
  font-size: 2.4rem;
  letter-spacing: 1px;
  margin-bottom: 10px;
}

header h2 {
  font-size: 1.1rem;
  font-weight: 400;
  opacity: 0.92;
}

nav {
  background: rgba(255, 255, 255, 0.96);
  backdrop-filter: blur(8px);
  display: flex;
  justify-content: center;
  gap: 28px;
  padding: 16px 20px;
  position: sticky;
  top: 0;
  z-index: 100;
  box-shadow: 0 4px 12px rgba(0, 0, 0, 0.06);
  flex-wrap: wrap;
}

nav a {
  font-size: 1rem;
  font-weight: 600;
  color: #234;
  padding: 10px 18px;
  border-radius: 999px;
  transition: all 0.25s ease;
}

nav a:hover,
nav a.active {
  background: #3b94ee;
  color: #fff;
}

.page {
  display: none;
  max-width: 1100px;
  margin: 0 auto;
  padding: 48px 22px 70px;
  animation: fadeIn 0.35s ease;
}

.page.active {
  display: block;
}

.hero {
  display: grid;
  grid-template-columns: 1.2fr 0.8fr;
  gap: 28px;
  align-items: center;
  margin-bottom: 34px;
}

.card {
  background: #fff;
  border-radius: 20px;
  padding: 28px;
  box-shadow: 0 12px 30px rgba(31, 93, 139, 0.08);
}

.hero h3 {
  font-size: 1.8rem;
  margin-bottom: 16px;
  color: #17324d;
}

.hero p,
.section p,
.paper-item p,
.platform-box p,
.function-card p,
.admin-card p {
  color: #1d1d3a;
}

.hero-image {
  min-height: 260px;
  border-radius: 22px;
  background: linear-gradient(135deg, #cfe4f5, #e9f3fb);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 4rem;
  color: #1f5d8b;
  box-shadow: inset 0 0 0 1px rgba(31, 93, 139, 0.08);
}

.section-title {
  font-size: 1.45rem;
  margin-top: 22px;
  margin-bottom: 8px;
  color: #17324d;
}

.info-grid,
.paper-list,
.platform-grid,
.function-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
  gap: 8px;
}

.info-item h4,
.paper-item h4,
.platform-box h4,
.function-card h4,
.admin-card h4 {
  margin-bottom: 10px;
  color: #1f4d73;
}

.paper-item,
.platform-box,
.info-item,
.function-card,
.admin-card {
  background: white;
  border-radius: 18px;
  padding: 22px;
  box-shadow: 0 10px 24px rgba(0, 0, 0, 0.06);
  transition: transform 0.2s ease, box-shadow 0.2s ease;
  margin: 10px 5px;
}

.paper-item:hover,
.platform-box:hover,
.info-item:hover,
.function-card:hover,
.admin-card:hover {
  transform: translateY(-6px);
  box-shadow: 0 14px 28px rgba(0, 0, 0, 0.08);
}

.tag {
  display: inline-block;
  margin-top: 12px;
  margin-right: 8px;
  padding: 6px 12px;
  border-radius: 999px;
  background: #e8f2fa;
  color: #1f5d8b;
  font-size: 0.88rem;
  font-weight: 600;
  border: none;
}

.tag a {
  display: inline-block;
}

.tag:hover,
button.tag:hover {
  background: #d8ebfb;
  color: #16527d;
}

.member-photo {
  margin-bottom: 12px;
}

.member-photo img {
  width: 180px;
  height: 220px;
  object-fit: cover;
  border-radius: 10px;
  display: block;
}

footer {
  text-align: center;
  padding: 16px 16px 40px;
  color: #5d6f82;
  font-size: 0.95rem;
}

/* ===== 登录 / 注册页 ===== */
.auth-page {
  display: block;
}

.auth-wrap {
  max-width: 820px;
  margin: 0 auto;
}

.auth-box {
  background: white;
  border-radius: 18px;
  padding: 28px;
  box-shadow: 0 10px 24px rgba(0, 0, 0, 0.06);
  transition: transform 0.2s ease, box-shadow 0.2s ease;
  margin: 10px 5px;
}

.auth-box:hover {
  transform: translateY(-4px);
  box-shadow: 0 14px 28px rgba(0, 0, 0, 0.08);
}

.auth-desc {
  margin-bottom: 18px;
  color: #1d1d3a;
}

.auth-form {
  display: flex;
  flex-direction: column;
  gap: 16px;
  margin-top: 16px;
}

.auth-form label {
  font-weight: 600;
  color: #1f4d73;
  margin-bottom: 6px;
  display: block;
}

.auth-form input[type="text"],
.auth-form input[type="password"],
.auth-form input[type="tel"] {
  width: 100%;
  padding: 12px 14px;
  border: 1px solid #d7e3ef;
  border-radius: 12px;
  outline: none;
  font-size: 15px;
  background: #f9fcff;
  color: #1f2d3d;
  transition: border-color 0.25s ease, box-shadow 0.25s ease;
}

.auth-form input[type="text"]:focus,
.auth-form input[type="password"]:focus,
.auth-form input[type="tel"]:focus {
  border-color: #3b94ee;
  box-shadow: 0 0 0 4px rgba(59, 148, 238, 0.12);
  background: #fff;
}

.auth-row {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 18px;
}

.auth-ops {
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: 12px;
  flex-wrap: wrap;
  margin-top: 4px;
  color: #234;
}

.auth-ops label {
  margin: 0;
  display: flex;
  align-items: center;
  gap: 8px;
  font-weight: 400;
  color: #234;
}

.auth-link,
.auth-switch a {
  color: #1f5d8b;
  font-weight: 600;
}

.auth-link:hover,
.auth-switch a:hover {
  color: #3b94ee;
}

.auth-submit {
  margin-top: 6px;
  border: none;
  cursor: pointer;
  text-align: center;
}

.auth-note {
  margin-top: 18px;
  padding: 14px 16px;
  border-radius: 14px;
  background: #f7fbff;
  color: #4c6177;
  box-shadow: inset 0 0 0 1px rgba(31, 93, 139, 0.08);
}

.auth-switch {
  margin-top: 6px;
  color: #234;
}

.error-msg,
.success-msg {
  margin-top: 2px;
  font-size: 14px;
  min-height: 22px;
}

.error-msg {
  color: #d93025;
}

.success-msg {
  color: #188038;
}

.captcha-box {
  display: flex;
  align-items: center;
  gap: 12px;
  flex-wrap: wrap;
}

.captcha-box img {
  height: 42px;
  min-width: 120px;
  border-radius: 10px;
  border: 1px solid #d7e3ef;
  background: #f7fbff;
  cursor: pointer;
}

.captcha-refresh {
  color: #1f5d8b;
  font-size: 14px;
  font-weight: 600;
  cursor: pointer;
}

/* ===== 功能页 ===== */
.function-page {
  display: block;
}

.function-hero {
  margin-bottom: 18px;
}

.function-user {
  margin-top: 8px;
  color: #4c6177;
  font-size: 0.96rem;
}

.function-card ul {
  padding-left: 20px;
  margin-top: 10px;
}

.function-card li {
  margin-bottom: 8px;
  color: #1d1d3a;
}

.back-link {
  margin-top: 12px;
  display: inline-block;
}

/* ===== 管理员页 ===== */
.admin-actions {
  margin-top: 12px;
}

.admin-status {
  display: inline-block;
  padding: 4px 10px;
  border-radius: 999px;
  font-size: 13px;
  font-weight: 600;
  background: #eef6fd;
  color: #1f5d8b;
}

.admin-status.pending {
  background: #fff3cd;
  color: #8a6d1d;
}

.admin-status.approved {
  background: #e8f7ee;
  color: #1c7c45;
}

.admin-status.rejected {
  background: #fdecec;
  color: #b42318;
}

.admin-status.disabled {
  background: #eef1f5;
  color: #475467;
}

.empty-box {
  background: #fff;
  border-radius: 18px;
  padding: 22px;
  box-shadow: 0 10px 24px rgba(0, 0, 0, 0.06);
  margin: 10px 5px;
  color: #5d6f82;
}

/* ===== 动画与响应式 ===== */
@keyframes fadeIn {
  from {
    opacity: 0;
    transform: translateY(8px);
  }

  to {
    opacity: 1;
    transform: translateY(0);
  }
}

@media (max-width: 820px) {
  header h1 {
    font-size: 1.8rem;
  }

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

  nav {
    gap: 10px;
  }

  .auth-row {
    grid-template-columns: 1fr;
    gap: 12px;
  }
}

@media (max-width: 640px) {
  .auth-box,
  .function-card,
  .admin-card,
  .platform-box,
  .info-item,
  .paper-item {
    padding: 20px;
  }

  .page {
    padding: 36px 16px 56px;
  }
}