/* ===== 全局美化升级 ===== */
body {
    font-family: 'Noto Sans SC', 'Roboto', 'Helvetica Neue', Arial, '思源黑体', sans-serif;
    margin: 0;
    padding: 0;
    background: #f7f9fb;
    color: #222;
    transition: background 0.3s, color 0.3s;
}

h1, h2 {
    text-align: center;
    font-weight: 700;
    letter-spacing: 1px;
}

/* ===== 北大红主题色 ===== */
:root {
  --main-gradient: linear-gradient(90deg, #232946 0%, #394867 100%);
  --main-color: #232946;
  --main-color-dark: #1a1f2b;
  --main-color-light: #5f6f94;
  --main-accent: #a7bbc7;
}

/* ===== 导航栏美化（加厚+北大红） ===== */
nav {
    position: fixed;
    top: 0;
    width: 100%;
  background: var(--main-gradient);
    color: white;
    z-index: 1000;
  box-shadow: 0 2px 8px rgba(0,0,0,0.08);
  transition: box-shadow 0.3s;
  height: 68px;
  display: flex;
  align-items: center;
}
nav ul {
    list-style: none;
    display: flex;
    justify-content: center;
  padding: 0;
  margin: 0 auto;
  gap: 10px;
  height: 100%;
  width: auto;
  margin: 0 auto;
  justify-content: center;
}
nav li {
  margin: 0 22px;
  height: 100%;
  display: flex;
  align-items: center;
}
nav a {
    color: white;
    text-decoration: none;
  font-weight: 700;
  font-size: 1.15em;
  padding: 12px 22px;
  border-radius: 8px;
  transition: background 0.2s, color 0.2s, box-shadow 0.2s;
  height: 44px;
  display: flex;
  align-items: center;
}
nav a:hover, nav a:focus {
  background: #394867;
  color: #fff;
  box-shadow: 0 2px 8px rgba(35,41,70,0.15);
}
nav a::after {
  background: var(--main-gradient);
}

/* ===== Hero Section 美化 ===== */
.hero {
    position: relative;
    height: 60vh;
    min-height: 320px;
    background-size: cover;
    background-position: center;
    display: flex;
    justify-content: center;
    align-items: center;
    border-radius: 0 0 24px 24px;
    box-shadow: 0 4px 24px rgba(74,144,226,0.08);
    overflow: hidden;
}
.hero h1 {
    color: white;
    font-size: 3em;
    text-shadow: 2px 2px 12px rgba(0,0,0,0.4);
    background: rgba(45,62,80,0.5);
    padding: 16px 32px;
    border-radius: 12px;
}

/* ===== 活动卡片美化 ===== */
.activities {
    display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 32px;
  padding: 32px 5vw 32px 5vw;
  margin-top: 80px;
}
.activity {
  display: flex;
  flex-direction: column;
  background: #fff;
  border-radius: 16px;
  box-shadow: 0 4px 24px rgba(74,144,226,0.10);
  position: relative;
  padding: 18px 16px 36px 16px;
  min-height: 320px;
  margin: 0;
}
.activity-date {
  font-size: 0.98em;
  color: #fff;
  background: #394867;
  display: block;
  padding: 6px 0;
  border-radius: 0 0 12px 12px;
  font-weight: bold;
  letter-spacing: 1px;
    text-align: center;
  position: absolute;
  left: 0;
  right: 0;
  bottom: 0;
  margin: 0;
}
.activity-carousel {
  position: relative;
  width: 100%;
  margin-bottom: 12px;
  overflow: hidden;
  border-radius: 10px;
  min-height: 200px; /* 添加最小高度 */
}
.activity-carousel img {
  width: 100%;
  height: auto;
  display: none;
  border-radius: 10px;
  box-shadow: 0 2px 8px rgba(74,144,226,0.10);
  object-fit: cover; /* 确保图片比例一致 */
}
.activity-carousel img.active {
  display: block;
}
.carousel-prev, .carousel-next {
  position: absolute;
  top: 50%;
  transform: translateY(-50%);
  background: rgba(35,41,70,0.8);
  color: #fff;
  border: none;
  border-radius: 50%;
  width: 50px;
  height: 50px;
  font-size: 1.5em;
  cursor: pointer;
  z-index: 10;
  transition: all 0.2s ease;
  display: flex;
  align-items: center;
  justify-content: center;
  line-height: 1;
  padding: 0;
  min-width: 50px;
  min-height: 50px;
}
.carousel-prev:hover, .carousel-next:hover {
  background: rgba(35,41,70,1);
  transform: translateY(-50%) scale(1.1);
}
.carousel-prev { left: 15px; }
.carousel-next { right: 15px; }
.activity-links {
  margin-top: 10px;
  padding-left: 0;
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
}
.activity-links li {
  margin-bottom: 0;
  list-style: none;
}
.activity-links a {
  display: inline-block;
  padding: 7px 18px;
  border-radius: 20px;
  background: linear-gradient(90deg, #5f6f94 0%, #a7bbc7 100%);
  color: #fff;
  font-weight: 600;
  font-size: 1em;
  text-decoration: none;
  box-shadow: 0 2px 8px rgba(74,144,226,0.10);
  transition: background 0.2s, color 0.2s, box-shadow 0.2s;
  margin-right: 0;
}
.activity-links a:hover {
  background: linear-gradient(90deg, #394867 0%, #5f6f94 100%);
  color: #fff;
  box-shadow: 0 4px 16px rgba(74,144,226,0.18);
}
@media (max-width: 900px) {
  .activities {
    grid-template-columns: 1fr;
  }
}

/* ===== 反馈区美化 ===== */
.feedback {
    padding: 32px 5vw 32px 5vw;
    margin-top: 80px;
    background: #fff;
    border-radius: 16px;
    box-shadow: 0 4px 24px rgba(74,144,226,0.10);
    max-width: 700px;
    margin-left: auto;
    margin-right: auto;
}
.feedback form {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 12px;
}
.feedback textarea {
    width: 90%;
    max-width: 500px;
    padding: 12px;
    margin-bottom: 10px;
    border-radius: 8px;
    border: 1px solid #d0d7de;
    font-size: 1em;
    transition: border 0.2s;
}
.feedback textarea:focus {
    border: 1.5px solid #4a90e2;
    outline: none;
}
.feedback button {
    padding: 10px 32px;
    background: var(--main-gradient);
    color: white;
    border: none;
    border-radius: 8px;
    font-size: 1.08em;
    font-weight: 600;
    cursor: pointer;
    box-shadow: 0 2px 8px rgba(74,144,226,0.10);
    transition: background 0.2s, box-shadow 0.2s;
}
.feedback button:hover {
    background: linear-gradient(90deg, #394867 0%, #232946 100%);
    box-shadow: 0 4px 16px rgba(74,144,226,0.18);
}
.comments p {
    background: #f0f4fa;
    padding: 12px;
    margin: 12px 0;
    border-radius: 8px;
    box-shadow: 0 2px 8px rgba(74,144,226,0.06);
}

/* ===== 团队成员卡片美化 ===== */
.team {
    display: flex;
    flex-wrap: wrap;
    justify-content: center;
    gap: 32px;
    padding: 32px 5vw 32px 5vw;
    margin-top: 80px;
}
.member {
    background: #fff;
    border-radius: 16px;
    box-shadow: 0 4px 24px rgba(74,144,226,0.10);
    text-align: center;
    padding: 24px 16px 16px 16px;
    width: 220px;
    transition: transform 0.2s, box-shadow 0.2s;
}
.member:hover {
    transform: translateY(-6px) scale(1.04);
    box-shadow: 0 8px 32px rgba(74,144,226,0.18);
}
.member img {
    width: 120px;
    height: 120px;
    border-radius: 50%;
    object-fit: cover;
    box-shadow: 0 2px 8px rgba(74,144,226,0.10);
    transition: transform 0.2s, box-shadow 0.2s, border 0.2s;
    border: 3px solid transparent;
}
.member img:hover {
    transform: scale(1.08);
    border: 3px solid #5f2eea;
    box-shadow: 0 0 0 6px #a7bbc755;
}
.member p {
    margin-top: 14px;
    font-weight: bold;
    font-size: 1.1em;
}

/* ===== 加入我们区美化 ===== */
.join-us {
    padding: 32px 5vw 32px 5vw;
    margin-top: 80px;
    background: #fff;
    border-radius: 16px;
    box-shadow: 0 4px 24px rgba(74,144,226,0.10);
    max-width: 900px;
    margin-left: auto;
    margin-right: auto;
}
.join-hero {
  background: linear-gradient(90deg, #5f6f94 0%, #a7bbc7 100%);
  color: #fff;
  text-align: center;
  padding: 72px 10px 48px 10px;
  border-radius: 18px 18px 0 0;
  margin-bottom: 0;
}
.join-hero h1 {
  font-size: 2.2em;
  font-weight: 800;
  margin-bottom: 12px;
  letter-spacing: 2px;
}
.join-slogan {
  font-size: 1.2em;
  font-weight: 500;
  margin-bottom: 0;
}
.advantages {
  display: flex;
  flex-wrap: wrap;
  gap: 24px;
  justify-content: center;
  margin: 32px 0 24px 0;
}
.advantage-card {
  background: linear-gradient(120deg, #a7bbc7, #5f6f94, #a7bbc7 80%);
  background-size: 200% 200%;
  background-position: 0% 50%;
  border-radius: 14px;
  box-shadow: 0 2px 12px rgba(74,144,226,0.10);
  padding: 32px 18px;
  min-height: 180px;
  text-align: center;
  display: flex;
  flex-direction: column;
  justify-content: center;
  position: relative;
  overflow: hidden;
  z-index: 1;
  animation: wave-gradient 6s linear infinite;
}
@keyframes wave-gradient {
  0% {
    background-position: 0% 50%;
  }
  100% {
    background-position: 100% 50%;
  }
}
.advantage-card h2, .advantage-card p {
  color: #fff;
  text-shadow: 0 2px 8px rgba(35,41,70,0.10);
}
.join-method {
    text-align: center;
  margin-top: 24px;
}
 /* ===== 联系方式图标美化 ===== */
 .contact-methods {
   display: flex;
   flex-direction: row;
   gap: 24px;
   margin: 32px 0 24px 0;
   align-items: center;
   justify-content: center;
   flex-wrap: wrap;
 }
 .contact-item {
   display: flex;
   align-items: center;
   gap: 20px;
   background: linear-gradient(135deg, #f7f9fb 0%, #eaf2fb 100%);
   border-radius: 16px;
   padding: 24px 32px;
   box-shadow: 0 4px 16px rgba(74,144,226,0.08);
   transition: transform 0.3s, box-shadow 0.3s;
   min-width: 320px;
   max-width: 400px;
 }
 .contact-item:hover {
   transform: translateY(-4px);
   box-shadow: 0 8px 24px rgba(74,144,226,0.15);
 }
 .contact-icon {
   width: 60px;
   height: 60px;
   border-radius: 50%;
   background: linear-gradient(135deg, #4a90e2 0%, #357ab8 100%);
   display: flex;
   align-items: center;
   justify-content: center;
   box-shadow: 0 4px 12px rgba(74,144,226,0.2);
   transition: transform 0.3s;
 }
 .contact-icon:hover {
   transform: scale(1.1);
 }
 .contact-icon i {
   font-size: 28px;
   color: white;
 }
 .contact-info {
   flex: 1;
 }
 .contact-info h3 {
   margin: 0 0 8px 0;
   font-size: 1.1em;
   font-weight: 600;
   color: #394867;
 }
 .contact-value {
   margin: 0;
   font-size: 1.05em;
   font-weight: 500;
   color: #5f6f94;
   word-break: break-all;
 }
 .contact-value a {
   color: #4a90e2;
   text-decoration: none;
   transition: color 0.2s;
 }
 .contact-value a:hover {
   color: #357ab8;
   text-decoration: underline;
 }
.join-welcome {
  margin-top: 18px;
  font-size: 1.1em;
  color: #394867;
  font-weight: 600;
}
.advantages-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  grid-template-rows: 1fr 1fr;
  gap: 24px;
  justify-content: center;
  margin: 32px 0 24px 0;
}
.join-steps {
  text-align: left;
  display: inline-block;
  margin: 0 0 12px 0;
  padding-left: 1.2em;
  font-size: 1.08em;
  color: #394867;
  font-weight: 500;
}
.join-steps li {
  margin-bottom: 6px;
  line-height: 1.7;
}
@media (max-width: 900px) {
  .advantages-grid {
    grid-template-columns: 1fr;
    grid-template-rows: none;
  }
  .advantage-card {
    width: 90%;
    max-width: 400px;
    margin: 0 auto;
  }
}

/* ===== 全局过渡动画 ===== */
* {
    transition: background 0.2s, color 0.2s, box-shadow 0.2s, border 0.2s, transform 0.2s;
}

/* ===== 响应式优化 ===== */
@media (max-width: 900px) {
    .activities, .team, .advantages {
        grid-template-columns: 1fr !important;
        flex-direction: column !important;
        align-items: center !important;
    }
    .member, .activities article, .advantages article {
        width: 90% !important;
        max-width: 400px;
    }
    .contact-methods {
        flex-direction: column;
        gap: 16px;
    }
    .contact-item {
        min-width: 280px;
        padding: 20px 24px;
    }
    .contact-icon {
        width: 50px;
        height: 50px;
    }
    .contact-icon i {
        font-size: 24px;
    }
    .hero-carousel {
        height: 50vh;
        min-height: 280px;
    }
    .carousel-btn {
        width: 40px;
        height: 40px;
        font-size: 1.2em;
    }
    .carousel-btn.prev { left: 16px; }
    .carousel-btn.next { right: 16px; }
    .carousel-dots {
        bottom: 16px;
    }
    .carousel-dots .dot {
        width: 10px;
        height: 10px;
        margin: 0 4px;
    }
    .activity-carousel {
        min-height: 280px;
    }
    .activity-carousel .carousel-prev,
    .activity-carousel .carousel-next {
        width: 40px;
        height: 40px;
        font-size: 1.2em;
    }
}
@media (max-width: 768px) {
    nav {
        height: auto;
        padding: 8px 0;
    }
    nav ul {
        flex-direction: row;
        flex-wrap: wrap;
        justify-content: center;
        gap: 4px;
        padding: 0 10px;
    }
    nav li {
        margin: 2px;
    }
    nav a {
        font-size: 0.9em;
        padding: 8px 12px;
        height: 36px;
    }
    .hero {
        height: 36vh;
        min-height: 180px;
    }
    .feedback, .join-us {
        padding: 18px 2vw 18px 2vw;
    }
    .join-qr {
        width: 280px;
        height: 560px;
    }
    .hero-carousel {
        height: 45vh;
        min-height: 240px;
    }
    .carousel-btn {
        width: 36px;
        height: 36px;
        font-size: 1em;
    }
    .carousel-btn.prev { left: 12px; }
    .carousel-btn.next { right: 12px; }
    .advantages-grid {
        grid-template-columns: 1fr;
        gap: 20px;
    }
    .advantage-card {
        padding: 24px 20px;
    }
    .join-hero h1 {
        font-size: 1.8em;
        padding: 12px 16px;
    }
    .join-slogan {
        font-size: 1.1em;
        padding: 0 20px;
    }
    .activity-carousel {
        min-height: 260px;
    }
    .activity-carousel .carousel-prev,
    .activity-carousel .carousel-next {
        width: 36px;
        height: 36px;
        font-size: 1em;
    }
}
@media (max-width: 480px) {
    nav {
        padding: 6px 0;
    }
    nav ul {
        gap: 2px;
        padding: 0 8px;
    }
    nav a {
        font-size: 0.8em;
        padding: 6px 8px;
        height: 32px;
    }
    .hero h1 {
        font-size: 1.5em;
        padding: 8px 10px;
    }
    .feedback, .join-us {
        padding: 8px 0 8px 0;
    }
    .contact-item {
        min-width: 240px;
        padding: 16px 20px;
        flex-direction: column;
        text-align: center;
        gap: 16px;
    }
    .contact-icon {
        width: 45px;
        height: 45px;
    }
    .contact-icon i {
        font-size: 20px;
    }
    .contact-info h3 {
        font-size: 1em;
    }
    .contact-value {
        font-size: 0.95em;
    }
    .join-qr {
        width: 200px;
        height: 400px;
    }
    .hero-carousel {
        height: 40vh;
        min-height: 200px;
    }
    .carousel-btn {
        width: 32px;
        height: 32px;
        font-size: 0.9em;
    }
    .carousel-btn.prev { left: 8px; }
    .carousel-btn.next { right: 8px; }
    .carousel-dots {
        bottom: 12px;
    }
    .carousel-dots .dot {
        width: 8px;
        height: 8px;
        margin: 0 3px;
    }
    .join-hero h1 {
        font-size: 1.5em;
        padding: 10px 12px;
    }
    .join-slogan {
        font-size: 1em;
        padding: 0 16px;
    }
    .advantage-card {
        padding: 20px 16px;
    }
    .advantage-card h2 {
        font-size: 1.3em;
    }
    .advantage-card p {
        font-size: 0.95em;
    }
    .contact-methods {
        gap: 12px;
    }
    .contact-item {
        min-width: 200px;
        padding: 14px 16px;
    }
    .contact-icon {
        width: 40px;
        height: 40px;
    }
    .contact-icon i {
        font-size: 18px;
    }
    .contact-info h3 {
        font-size: 0.95em;
    }
    .contact-value {
        font-size: 0.9em;
    }
    .join-welcome {
        font-size: 1em;
        padding: 0 16px;
    }
    .activity-carousel {
        min-height: 220px;
    }
    .activity-carousel .carousel-prev,
    .activity-carousel .carousel-next {
        width: 32px;
        height: 32px;
        font-size: 0.9em;
    }
    .activity-links {
        flex-direction: column;
        gap: 8px;
    }
    .activity-links a {
        font-size: 0.9em;
        padding: 6px 14px;
    }
    .member {
        width: 200px;
        padding: 24px 16px 16px 16px;
    }
    .member img {
        width: 110px;
        height: 110px;
    }
    .member p {
        font-size: 1.05em;
    }
    .member-role {
        font-size: 1em;
        padding: 4px 14px;
    }
    .team-intro, .team-summary {
        font-size: 1.05em;
        padding: 0 20px;
    }
    .feedback {
        padding: 32px 4vw 32px 4vw;
        max-width: 700px;
    }
    .feedback h2 {
        font-size: 1.6em;
        margin-bottom: 20px;
    }
}

/* ===== 大屏幕设备 (1400px以上) ===== */
@media (min-width: 1400px) {
    .hero-carousel {
        height: 65vh;
        min-height: 400px;
    }
    .carousel-btn {
        width: 56px;
        height: 56px;
        font-size: 1.6em;
    }
    .carousel-btn.prev { left: 32px; }
    .carousel-btn.next { right: 32px; }
    .carousel-dots {
        bottom: 24px;
    }
    .carousel-dots .dot {
        width: 14px;
        height: 14px;
        margin: 0 6px;
    }
    .join-hero h1 {
        font-size: 2.2em;
        padding: 16px 20px;
    }
    .join-slogan {
        font-size: 1.3em;
        padding: 0 24px;
    }
    .advantage-card {
        padding: 36px 28px;
    }
    .advantage-card h2 {
        font-size: 1.6em;
    }
    .advantage-card p {
        font-size: 1.1em;
    }
    .contact-item {
        min-width: 320px;
        padding: 28px 32px;
    }
    .contact-icon {
        width: 60px;
        height: 60px;
    }
    .contact-icon i {
        font-size: 28px;
    }
    .contact-info h3 {
        font-size: 1.2em;
    }
    .contact-value {
        font-size: 1.1em;
    }
    .join-welcome {
        font-size: 1.2em;
        padding: 0 24px;
    }
    .join-qr {
        width: 400px;
        height: 800px;
    }
    .activity-carousel {
        min-height: 350px;
    }
    .activity-carousel .carousel-prev,
    .activity-carousel .carousel-next {
        width: 48px;
        height: 48px;
        font-size: 1.6em;
    }
    .activity-links a {
        font-size: 1.1em;
        padding: 8px 20px;
    }
    .member {
        width: 240px;
        padding: 28px 20px 20px 20px;
    }
    .member img {
        width: 140px;
        height: 140px;
    }
    .member p {
        font-size: 1.2em;
    }
    .member-role {
        font-size: 1.1em;
        padding: 6px 18px;
    }
    .team-intro, .team-summary {
        font-size: 1.2em;
        padding: 0 24px;
    }
    .feedback {
        padding: 40px 6vw 40px 6vw;
        max-width: 800px;
    }
    .feedback h2 {
        font-size: 1.8em;
        margin-bottom: 24px;
    }
}

/* ===== 超小屏幕设备 (320px以下) ===== */
@media (max-width: 320px) {
    .hero h1 {
        font-size: 1.3em;
        padding: 6px 8px;
    }
    .hero-carousel {
        height: 35vh;
        min-height: 180px;
    }
    .carousel-btn {
        width: 28px;
        height: 28px;
        font-size: 0.8em;
    }
    .carousel-btn.prev { left: 6px; }
    .carousel-btn.next { right: 6px; }
    .join-hero h1 {
        font-size: 1.3em;
        padding: 8px 10px;
    }
    .join-slogan {
        font-size: 0.9em;
        padding: 0 12px;
    }
    .advantage-card {
        padding: 16px 12px;
    }
    .advantage-card h2 {
        font-size: 1.2em;
    }
    .advantage-card p {
        font-size: 0.9em;
    }
    .contact-item {
        min-width: 180px;
        padding: 12px 14px;
    }
    .contact-icon {
        width: 36px;
        height: 36px;
    }
    .contact-icon i {
        font-size: 16px;
    }
    .contact-info h3 {
        font-size: 0.9em;
    }
    .contact-value {
        font-size: 0.85em;
    }
    .join-qr {
        width: 160px;
        height: 320px;
    }
    .join-welcome {
        font-size: 0.9em;
        padding: 0 12px;
    }
    .feedback, .join-us {
        padding: 6px 0 6px 0;
    }
    nav {
        padding: 4px 0;
    }
    nav ul {
        gap: 1px;
        padding: 0 4px;
    }
    nav li {
        margin: 1px;
    }
    nav a {
        font-size: 0.75em;
        padding: 4px 6px;
        height: 28px;
    }
    .activity-carousel {
        min-height: 200px;
    }
    .activity-carousel .carousel-prev,
    .activity-carousel .carousel-next {
        width: 28px;
        height: 28px;
        font-size: 0.8em;
    }
    .activity-links a {
        font-size: 0.85em;
        padding: 5px 12px;
    }
    .member {
        width: 180px;
        padding: 20px 12px 12px 12px;
    }
    .member img {
        width: 100px;
        height: 100px;
    }
    .member p {
        font-size: 1em;
    }
    .member-role {
        font-size: 0.9em;
        padding: 3px 12px;
    }
    .team-intro, .team-summary {
        font-size: 1em;
        padding: 0 16px;
    }
    .feedback {
        padding: 16px 2vw 16px 2vw;
        max-width: 450px;
    }
    .feedback h2 {
        font-size: 1.1em;
        margin-bottom: 10px;
    }
}

/* ===== 导航栏下划线动画 ===== */
nav a {
    position: relative;
    overflow: hidden;
}
nav a::after {
    content: '';
    position: absolute;
    left: 50%;
    bottom: 2px;
    width: 0;
    height: 2.5px;
    background: linear-gradient(90deg, #4a90e2 60%, #357ab8 100%);
    border-radius: 2px;
    transition: all 0.3s cubic-bezier(.4,0,.2,1);
    transform: translateX(-50%);
}
nav a:hover::after, nav a:focus::after {
    width: 80%;
}

/* ===== 按钮动效增强 ===== */
.feedback button, .join-method a, button, .btn {
    position: relative;
    overflow: hidden;
}
.feedback button:active, .join-method a:active, button:active, .btn:active {
    transform: scale(0.96);
    box-shadow: 0 2px 8px rgba(74,144,226,0.18);
}

/* ===== 图片悬停动效增强 ===== */
.activities img, .advantages img, .member img {
    transition: transform 0.3s cubic-bezier(.4,0,.2,1), box-shadow 0.3s;
}
.activities img:hover, .advantages img:hover, .member img:hover {
    transform: scale(1.08) rotate(-2deg);
    box-shadow: 0 8px 32px rgba(74,144,226,0.22);
}

/* ===== 内容块淡入动画 ===== */
.fade-in {
    opacity: 0;
    transform: translateY(40px);
    transition: opacity 0.7s cubic-bezier(.4,0,.2,1), transform 0.7s cubic-bezier(.4,0,.2,1);
}
.fade-in.visible {
    opacity: 1;
    transform: none;
}

/* ===== 返回顶部按钮样式 ===== */
#backToTop {
    display: none;
    position: fixed;
    right: 32px;
    bottom: 48px;
    z-index: 2000;
    background: linear-gradient(90deg, #4a90e2 60%, #357ab8 100%);
    color: #fff;
    border: none;
    border-radius: 50%;
    width: 48px;
    height: 48px;
    font-size: 2em;
    box-shadow: 0 4px 16px rgba(74,144,226,0.18);
    cursor: pointer;
    transition: background 0.2s, box-shadow 0.2s, transform 0.2s;
}

/* 响应式返回顶部按钮 */
@media (max-width: 768px) {
    #backToTop {
        right: 24px;
        bottom: 40px;
        width: 44px;
        height: 44px;
        font-size: 1.8em;
    }
}

@media (max-width: 480px) {
    #backToTop {
        right: 20px;
        bottom: 32px;
        width: 40px;
        height: 40px;
        font-size: 1.6em;
    }
}

@media (max-width: 320px) {
    #backToTop {
        right: 16px;
        bottom: 28px;
        width: 36px;
        height: 36px;
        font-size: 1.4em;
    }
}

@media (min-width: 1400px) {
    #backToTop {
        right: 40px;
        bottom: 56px;
        width: 56px;
        height: 56px;
        font-size: 2.2em;
    }
}
#backToTop:hover {
    background: linear-gradient(90deg, #357ab8 60%, #4a90e2 100%);
    transform: scale(1.08);
}

/* ===== 按钮波纹动效 ===== */
.ripple {
  position: absolute;
  border-radius: 50%;
  transform: scale(0);
  animation: ripple 0.6s linear;
  background: rgba(255,255,255,0.5);
  pointer-events: none;
  z-index: 2;
}
@keyframes ripple {
  to {
    transform: scale(2.5);
    opacity: 0;
  }
}

/* ===== 首页轮播大图样式 ===== */
.hero-carousel {
  position: relative;
  height: 60vh;
  min-height: 320px;
  background: #eaf2fb;
  border-radius: 0 0 24px 24px;
  box-shadow: 0 4px 24px rgba(74,144,226,0.08);
  overflow: hidden;
  display: flex;
  align-items: center;
  justify-content: center;
}
.carousel-images {
  width: 100%;
  height: 100%;
  position: absolute;
  top: 0; left: 0;
  z-index: 1;
}
.carousel-item {
  width: 100%;
  height: 100%;
  background-size: cover;
  background-position: center;
  position: absolute;
  top: 0; left: 0;
  opacity: 0;
  transition: opacity 0.7s cubic-bezier(.4,0,.2,1);
  z-index: 1;
}
.carousel-item.active {
  opacity: 1;
  z-index: 2;
}
.carousel-btn {
  position: absolute;
  top: 50%;
  transform: translateY(-50%);
  background: rgba(45,62,80,0.6);
  color: #fff;
  border: none;
  border-radius: 50%;
  width: 40px;
  height: 40px;
  font-size: 1.6em;
  cursor: pointer;
  z-index: 3;
  transition: background 0.2s, transform 0.2s;
}
.carousel-btn:hover {
  background: #4a90e2;
  transform: translateY(-50%) scale(1.08);
}
.carousel-btn.prev { left: 24px; }
.carousel-btn.next { right: 24px; }
.carousel-dots {
  position: absolute;
  bottom: 18px;
  left: 50%;
  transform: translateX(-50%);
  display: flex;
  gap: 10px;
  z-index: 3;
}
.carousel-dots .dot {
  width: 12px;
  height: 12px;
  border-radius: 50%;
  background: #fff;
  opacity: 0.5;
  cursor: pointer;
  transition: opacity 0.2s, background 0.2s;
  border: 2px solid #4a90e2;
}
.carousel-dots .dot.active {
  background: #4a90e2;
  opacity: 1;
}
.hero-caption {
  position: absolute;
  left: 50%;
  top: 60%;
  transform: translate(-50%, -50%);
  z-index: 4;
  background: rgba(45,62,80,0.5);
  padding: 16px 32px;
  border-radius: 12px;
}

/* ===== 轮播图去除文字 ===== */
.hero-caption { display: none !important; }

/* ===== 打字动画全屏遮罩 ===== */
#typing-mask {
  position: fixed;
  z-index: 3000;
  left: 0; top: 0; right: 0; bottom: 0;
  background: url('/images/loading.jpg') center center/cover no-repeat;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  font-family: 'Noto Sans SC', 'Roboto', Arial, sans-serif;
  font-size: 2.2em;
  color: #fff;
  letter-spacing: 2px;
  transition: opacity 0.6s;
}
#typing-mask::before {
  content: '';
  position: absolute;
  left: 0; top: 0; right: 0; bottom: 0;
  background: rgba(35,41,70,0.55);
  z-index: 1;
}
#typing-mask .typing-text {
  white-space: pre-line;
  border-right: 2px solid #fff;
  padding-right: 6px;
  animation: blink-cursor 1s steps(1) infinite;
  position: relative;
  z-index: 2;
}
@keyframes blink-cursor {
  0%, 100% { border-color: var(--pkured); }
  50% { border-color: transparent; }
}



/* ===== 首页互动区块 ===== */
.recent-section, .recent-style-section, .thanks-section {
  background: transparent;
  border-radius: 0;
  box-shadow: none;
  margin: 0;
  padding: 0;
  max-width: none;
}
.recent-section h2, .recent-style-section h2, .thanks-section h2 {
  margin-bottom: 18px;
}
.recent-list {
  list-style: none;
  padding: 0;
  margin: 0;
}
.recent-list li {
  margin-bottom: 12px;
  font-size: 1.08em;
  display: flex;
  align-items: center;
  gap: 10px;
}
.recent-list a {
  color: #4a90e2;
  text-decoration: underline;
  transition: color 0.2s;
}
.recent-list a:hover {
  color: #357ab8;
}
.recent-list .date {
  color: #888;
  font-size: 0.95em;
}

.recent-style-list {
  display: flex;
  gap: 32px;
  flex-wrap: wrap;
  justify-content: flex-start;
}
.style-item {
  background: #f7f9fb;
  border-radius: 12px;
  box-shadow: 0 2px 8px rgba(74,144,226,0.06);
  padding: 16px 12px 12px 12px;
  text-align: center;
  width: 180px;
  transition: transform 0.2s, box-shadow 0.2s;
}
.style-item img {
  width: 100px;
  height: 100px;
  border-radius: 50%;
  object-fit: cover;
  margin-bottom: 10px;
  box-shadow: 0 2px 8px rgba(74,144,226,0.10);
}

.thanks-list {
  display: flex;
  flex-wrap: wrap;
  gap: 32px;
  align-items: center;
}
.thanks-item {
  display: flex;
  align-items: center;
  gap: 18px;
  background: #f7f9fb;
  border-radius: 12px;
  box-shadow: 0 2px 8px rgba(74,144,226,0.06);
  padding: 18px 20px;
}
.thanks-item img {
  width: 80px;
  height: 80px;
  border-radius: 50%;
  object-fit: cover;
  box-shadow: 0 2px 8px rgba(74,144,226,0.10);
}

@media (max-width: 900px) {
  .recent-style-list, .thanks-list {
        flex-direction: column;
        align-items: center;
    }
  .style-item, .thanks-item {
    width: 90% !important;
    max-width: 400px;
  }
}

/* ===== 九章征解区块 ===== */
.challenge-section {
  background: transparent;
  border-radius: 0;
  box-shadow: none;
  margin: 0;
  padding: 0;
  max-width: none;
}
.challenge-section h2 {
  margin-bottom: 18px;
}
.challenge-list {
  display: flex;
  flex-wrap: wrap;
  gap: 32px;
  align-items: center;
}
.challenge-item {
  background: #f7f9fb;
  border-radius: 12px;
  box-shadow: 0 2px 8px rgba(74,144,226,0.06);
  padding: 18px 24px;
  display: flex;
  align-items: center;
  gap: 18px;
  font-size: 1.1em;
}
.challenge-label {
  background: #394867;
  color: #fff;
  border-radius: 8px;
  padding: 4px 14px;
  font-weight: bold;
  margin-right: 10px;
  font-size: 1em;
}
.challenge-link {
  color: #357ab8;
  text-decoration: underline;
  font-weight: 600;
  transition: color 0.2s;
}
.challenge-link:hover {
  color: #d2691e;
}

#global-toast {
  position: fixed;
  left: 50%;
  bottom: 12%;
  transform: translateX(-50%);
  min-width: 160px;
  max-width: 80vw;
  background: rgba(35,41,70,0.98);
  color: #fff;
  font-size: 1.1em;
  padding: 16px 32px;
  border-radius: 16px;
  box-shadow: 0 4px 24px rgba(35,41,70,0.18);
  text-align: center;
  z-index: 5000;
  opacity: 0;
  pointer-events: none;
  transition: opacity 0.4s;
}
#global-toast.show {
  opacity: 1;
  pointer-events: auto;
}

.team-intro {
  font-size: 1.15em;
  color: #394867;
  background: #f0f4fa;
  border-radius: 12px;
  padding: 18px 24px;
  margin-bottom: 32px;
  text-align: center;
  font-weight: 500;
}
.team-summary {
  font-size: 1.08em;
  color: #fff;
  background: #5f6f94;
  border-radius: 12px;
  padding: 16px 20px;
  margin-top: 36px;
  text-align: center;
  font-weight: 500;
  box-shadow: 0 2px 8px rgba(74,144,226,0.10);
}
.member-role {
  margin-top: 8px;
  font-size: 1em;
  color: #fff;
  background: linear-gradient(90deg, #5f6f94 0%, #a7bbc7 100%);
  border-radius: 10px;
  padding: 4px 16px;
  display: inline-block;
  font-weight: 600;
  letter-spacing: 1px;
}
.join-qr-area {
  display: flex;
  flex-direction: column;
  align-items: center;
  margin: 18px 0 10px 0;
}
.join-qr {
  width: 350px;
  height: 700px;
  border-radius: 16px;
  box-shadow: 0 2px 12px rgba(74,144,226,0.10);
  margin-bottom: 8px;
  background: #fff;
  object-fit: cover;
}
.join-qr-tip {
  color: #394867;
  font-size: 1em;
  margin-top: 0;
  font-weight: 500;
}

/* ===== 主页左右分栏布局 ===== */
.homepage-layout {
  display: flex;
  gap: 24px;
  padding: 40px 5vw;
  max-width: 1400px;
  margin: 0 auto;
}

.left-column {
  flex: 2;
  display: flex;
  flex-direction: column;
  gap: 24px;
}

.right-column {
  flex: 1;
  display: flex;
  flex-direction: column;
  gap: 24px;
}

.grid-item {
  background: #fff;
  border-radius: 16px;
  box-shadow: 0 4px 24px rgba(74,144,226,0.10);
  padding: 32px 24px 24px 24px;
  transition: transform 0.3s ease, box-shadow 0.3s ease;
  text-align: center;
}

.grid-item:hover {
  transform: translateY(-4px);
  box-shadow: 0 8px 32px rgba(74,144,226,0.15);
}

/* 响应式布局调整 */
@media (max-width: 1200px) {
  .homepage-layout {
    gap: 20px;
    padding: 32px 4vw;
  }
  
  .left-column,
  .right-column {
    gap: 20px;
  }
}

@media (max-width: 900px) {
  .homepage-layout {
    flex-direction: column;
    gap: 16px;
    padding: 24px 3vw;
  }
  
  .left-column,
  .right-column {
    gap: 16px;
  }
}

@media (max-width: 600px) {
  .homepage-layout {
    gap: 20px;
    padding: 20px 4vw;
  }
  
  .left-column,
  .right-column {
    gap: 20px;
  }
}

/* 调整原有区块样式以适应新布局 */
.recent-section, .recent-style-section, .thanks-section {
  margin: 0;
  max-width: none;
}

.challenge-section {
  margin: 0;
  max-width: none;
}

/* 优化卡片内容布局 */
.grid-item h2 {
  margin-bottom: 20px;
  font-size: 1.4em;
  color: #232946;
  text-align: center;
}

/* 调整列表样式 */
.recent-list {
  text-align: center;
}

.recent-list li {
  margin-bottom: 16px;
  font-size: 1.05em;
  line-height: 1.5;
  text-align: center;
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 8px;
}

/* 优化挑战项目样式 */
.challenge-item {
  padding: 16px 20px;
  font-size: 1.05em;
  text-align: center;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  min-height: 120px;
}

/* 优化致谢内容样式 */
.thanks-content {
  text-align: center;
  line-height: 1.6;
}

.thanks-content p {
  margin: 12px 0;
  font-size: 1.05em;
  color: #394867;
}

/* 调整挑战列表样式 */
.challenge-list {
  text-align: center;
  display: flex;
  justify-content: center;
  align-items: center;
  min-height: 120px;
}

.challenge-item {
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: 12px;
  width: 100%;
}

.challenge-label {
  margin-right: 0;
  margin-bottom: 8px;
}

.challenge-link {
  text-align: center;
  display: block;
  width: 100%;
}

/* 折叠卡片样式 */
.collapsible-list {
  flex-direction: column;
  gap: 18px;
  max-height: 420px;
  overflow-y: auto;
  padding-right: 4px;
}
.collapsible-card {
  flex-direction: column;
  width: 100%;
  min-width: 0;
  box-sizing: border-box;
  cursor: pointer;
  transition: box-shadow 0.2s;
}
.collapsible-card:hover {
  box-shadow: 0 4px 16px rgba(74,144,226,0.13);
}
.collapsible-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  width: 100%;
  font-weight: bold;
  font-size: 1.08em;
  user-select: none;
}
.collapsible-arrow {
  margin-left: 8px;
  font-size: 1.2em;
  color: #357ab8;
  transition: transform 0.2s;
}
.collapsible-content {
  width: 100%;
  margin-top: 8px;
  padding-left: 2px;
  transition: max-height 0.3s cubic-bezier(0.4,0,0.2,1);
  overflow: hidden;
}

/* 只显示3个卡片高度，超出可滚动 */
.scrollable-list {
  display: flex;
  flex-direction: column;
  gap: 18px;
  max-height: 270px; /* 3个卡片高度左右 */
  overflow-y: auto;
  padding-right: 4px;
}

/* 模拟期中考试竖直排列卡片 */
.exam-vertical-list {
  display: flex;
  flex-direction: column;
  justify-content: center;
  gap: 10px;
  align-items: stretch;
  padding: 0;
  padding: 40px; 
  margin: 0;
}
.exam-card {
  min-width: 0;
  max-width: 100%;
  height: 44px;
  background: linear-gradient(90deg, #394867 0%, #a7bbc7 100%);
  border-radius: 10px;
  box-shadow: 0 1px 4px rgba(35,41,70,0.08);
  padding: 0 16px;
  font-size: 1em;
  color: #fff;
  font-weight: 700;
  text-align: center;
  text-decoration: none;
  transition: background 0.16s, color 0.16s, box-shadow 0.16s, transform 0.13s, border 0.13s;
  white-space: nowrap;
  display: flex;
  align-items: center;
  justify-content: center;
  border: 2px solid transparent;
  letter-spacing: 1px;
  position: relative;
  margin: 0;
  overflow: hidden;
}
.exam-card:hover, .exam-card:focus {
  background: linear-gradient(90deg, #232946 0%, #5f6f94 100%);
  color: #fff;
  border: 2px solid #4a90e2;
  box-shadow: 0 4px 16px rgba(35,41,70,0.13);
  transform: translateY(-1px) scale(1.03);
  z-index: 2;
}
.exam-card:active {
  transform: scale(0.97);
  box-shadow: 0 1px 4px rgba(35,41,70,0.08);
}
/* 移除横向滚动样式 */
.exam-scroll-list { display: none !important; }