* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
  font-family: "Microsoft YaHei", sans-serif;
}
body {
  background: #0b0d1a;
  color: #fff;
  overflow-x: hidden;
}
#particles {
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  z-index: -1;
}
.nav {
  position: fixed;
  top: 0;
  width: 100%;
  background: rgba(0,0,0,0.7);
  padding: 18px 30px;
  display: flex;
  justify-content: space-between;
  align-items: center;
  z-index: 100;
  border-bottom: 1px solid #00e5ff;
}
.logo {
  font-size: 22px;
  color: #00e5ff;
  font-weight: bold;
}
.nav-menu {
  display: flex;
  gap: 24px;
}
.nav-menu a {
  color: #fff;
  text-decoration: none;
  padding: 8px 14px;
  border-radius: 8px;
  transition: 0.3s;
}
.nav-menu a.active,
.nav-menu a:hover {
  background: #00e5ff;
  color: #000;
}
.hero {
  width: 100%;
  height: 100vh;
  display: flex;
  flex-direction: column;
  justify-content: center;
  align-items: center;
  text-align: center;
  padding: 0 20px;
}
.hero h1 {
  font-size: 48px;
  background: linear-gradient(90deg, #00e5ff, #7e22ce);
  -webkit-background-clip: text;
  color: transparent;
  margin-bottom: 20px;
}
.hero p {
  font-size: 20px;
  color: #ccc;
  max-width: 700px;
}
.message-box {
  max-width: 900px;
  margin: 60px auto;
  background: rgba(20,22,38,0.9);
  padding: 40px;
  border-radius: 20px;
  border: 1px solid #00e5ff;
  box-shadow: 0 0 40px rgba(0,229,255,0.15);
}
.message-box h2 {
  text-align: center;
  font-size: 30px;
  color: #00e5ff;
  margin-bottom: 30px;
}
.input-group {
  display: flex;
  flex-direction: column;
  gap: 16px;
  margin-bottom: 20px;
}
.input-group input,
.input-group textarea {
  padding: 14px;
  border-radius: 10px;
  border: 1px solid #444;
  background: #151829;
  color: #fff;
  font-size: 16px;
  outline: none;
  transition: 0.3s;
}
.input-group input:focus,
.input-group textarea:focus {
  border-color: #00e5ff;
  box-shadow: 0 0 10px #00e5ff55;
}
textarea {
  min-height: 140px;
  resize: vertical;
}
.upload-bar {
  display: flex;
  gap: 12px;
  flex-wrap: wrap;
  margin-bottom: 20px;
}
.upload-btn {
  padding: 10px 16px;
  background: #1e2137;
  border: 1px solid #7e22ce;
  border-radius: 10px;
  color: #fff;
  cursor: pointer;
  transition: 0.3s;
}
.upload-btn:hover {
  background: #7e22ce;
}
.send-btn {
  padding: 16px;
  background: linear-gradient(90deg, #00e5ff, #7e22ce);
  border: none;
  border-radius: 12px;
  color: #fff;
  font-size: 18px;
  font-weight: bold;
  cursor: pointer;
  transition: 0.3s;
}
.send-btn:hover {
  transform: scale(1.03);
  box-shadow: 0 0 20px #00e5ff66;
}
.msg-list, .feed {
  margin-top: 40px;
}
.msg-item, .post-item {
  background: #181b2e;
  padding: 20px;
  border-radius: 14px;
  border-left: 4px solid #00e5ff;
  margin-bottom:15px;
}
.msg-item strong, .post-item strong {
  color: #00e5ff;
  font-size: 17px;
}
.msg-item p, .post-item p {
  margin: 10px 0;
  color: #eee;
}
.msg-item img {
  max-width: 100%;
  border-radius: 10px;
  margin: 10px 0;
}

/* 炫酷登录弹窗 */
.modal {
  display: none;
  position: fixed;
  z-index: 9999;
  left: 0;
  top: 0;
  width: 100%;
  height: 100%;
  background: rgba(0, 0, 0, 0.85);
  backdrop-filter: blur(6px);
  justify-content: center;
  align-items: center;
  animation: fadeIn 0.3s ease;
}

.modal-content {
  background: #121629;
  width: 90%;
  max-width: 420px;
  padding: 40px 30px;
  border-radius: 20px;
  border: 1px solid #00e5ff;
  box-shadow: 0 0 40px #00e5ff33;
  position: relative;
  text-align: center;
}

.modal-content h2 {
  color: #00e5ff;
  margin-bottom: 20px;
  font-size: 24px;
}

.close {
  position: absolute;
  right: 20px;
  top: 15px;
  font-size: 22px;
  color: #fff;
  cursor: pointer;
}

.tab {
  display: flex;
  gap: 10px;
  margin-bottom: 25px;
}

.tab button {
  flex: 1;
  padding: 12px;
  border: none;
  border-radius: 10px;
  background: #1b1f35;
  color: #fff;
  font-size: 16px;
  cursor: pointer;
  transition: 0.25s;
}

.tab button.active {
  background: #00e5ff;
  color: #000;
  font-weight: bold;
}

.tabcontent {
  display: none;
  animation: fadeIn 0.3s ease;
}

.tabcontent input {
  width: 100%;
  padding: 14px;
  margin-bottom: 15px;
  border-radius: 10px;
  border: 1px solid #444;
  background: #181c30;
  color: #fff;
  font-size: 15px;
  outline: none;
}

.tabcontent input:focus {
  border-color: #00e5ff;
  box-shadow: 0 0 10px #00e5ff55;
}

.tabcontent .btn {
  width: 100%;
  padding: 14px;
  border-radius: 10px;
  background: linear-gradient(90deg, #00e5ff, #7e22ce);
  color: #fff;
  border: none;
  font-size: 16px;
  font-weight: bold;
  cursor: pointer;
  margin-top: 5px;
}

@keyframes fadeIn {
  from { opacity: 0; transform: translateY(10px); }
  to { opacity: 1; transform: translateY(0); }
}