:root {
  --bg: #0e1014;
  --panel: #171a21;
  --panel2: #1f242e;
  --line: #2a313d;
  --text: #e7ecf3;
  --muted: #8b96a7;
  --primary: #6c8cff;
  --primary2: #8a6cff;
  --user: #2b3850;
  --admin: #384a2b;
  --danger: #ff6b6b;
}
* { box-sizing: border-box; }
html, body { margin: 0; height: 100%; }
body {
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC", "Microsoft YaHei", sans-serif;
  background: radial-gradient(1200px 600px at 70% -10%, #1b2030 0%, var(--bg) 60%);
  color: var(--text);
  -webkit-font-smoothing: antialiased;
}
#app { height: 100%; }
.screen { height: 100%; }
.hidden { display: none !important; }

/* 卡片 / 登录 */
.card {
  background: var(--panel);
  border: 1px solid var(--line);
  border-radius: 18px;
  padding: 28px;
}
#login { display: flex; align-items: center; justify-content: center; padding: 20px; }
.login-card { position: relative; width: 360px; max-width: 100%; }
.admin-entry {
  position: fixed; top: 8px; right: 10px; z-index: 20;
  font-size: 11px; color: var(--muted); background: transparent; border: none;
  cursor: pointer; padding: 4px 8px; border-radius: 8px; transition: .2s;
  text-decoration: none; opacity: .22; letter-spacing: 1px;
}
.admin-entry:hover { opacity: 1; color: var(--text); background: var(--panel2); }
.admin-entry.active { opacity: 1; color: var(--primary); }
.brand { text-align: center; margin-bottom: 18px; }
.logo {
  font-size: 30px; font-weight: 800; letter-spacing: 4px;
  background: linear-gradient(90deg, var(--primary), var(--primary2));
  -webkit-background-clip: text; background-clip: text; color: transparent;
}
.subtitle { color: var(--muted); margin: 6px 0 0; font-size: 13px; }
.form label { display: block; font-size: 12px; color: var(--muted); margin: 12px 0 6px; }
.form input {
  width: 100%; padding: 12px 14px; border-radius: 10px; border: 1px solid var(--line);
  background: var(--panel2); color: var(--text); font-size: 15px; outline: none;
}
.form input:focus { border-color: var(--primary); }
#login-form .btn.primary { width: 100%; margin-top: 18px; }

.btn {
  border: none; border-radius: 10px; padding: 11px 16px; cursor: pointer;
  font-size: 14px; font-weight: 600; transition: .15s;
}
.btn.primary { background: linear-gradient(90deg, var(--primary), var(--primary2)); color: #fff; }
.btn.primary:hover { filter: brightness(1.08); }
.btn.ghost { background: transparent; color: var(--muted); border: 1px solid var(--line); }
.btn.block { width: 100%; }
.err { color: var(--danger); font-size: 13px; min-height: 18px; margin: 10px 0 0; text-align: center; }

/* 顶栏 */
.topbar {
  height: 56px; display: flex; align-items: center; justify-content: space-between;
  padding: 0 18px; border-bottom: 1px solid var(--line); background: var(--panel);
}
.who { font-weight: 700; }

/* 布局 */
.layout { display: flex; height: calc(100% - 56px); }
.sidebar { width: 300px; border-right: 1px solid var(--line); background: var(--panel); overflow-y: auto; padding: 14px; }
.chat { flex: 1; overflow-y: auto; padding: 18px; }
.empty { color: var(--muted); display: flex; height: 100%; align-items: center; justify-content: center; }

/* 线程列表 */
.thread-list { margin-top: 14px; display: flex; flex-direction: column; gap: 8px; }
.thread {
  padding: 12px; border-radius: 12px; background: var(--panel2); border: 1px solid var(--line);
  cursor: pointer; transition: .15s;
}
.thread:hover { border-color: var(--primary); }
.thread.active { border-color: var(--primary); background: #20283a; }
.thread .t-subject { font-weight: 600; font-size: 14px; margin-bottom: 4px; display: flex; justify-content: space-between; }
.thread .t-meta { font-size: 12px; color: var(--muted); }
.badge { font-size: 11px; padding: 1px 7px; border-radius: 8px; background: #33404f; color: #cdd6e3; }
.badge.open { background: #1d3a2a; color: #7ee0a3; }
.badge.closed { background: #3a2330; color: #ff9ec0; }
.badge.unread { background: var(--danger); color: #fff; }

/* 聊天气泡 */
.msg { max-width: 74%; margin-bottom: 12px; padding: 10px 13px; border-radius: 14px; line-height: 1.5; word-break: break-word; }
.msg .who { font-size: 11px; color: var(--muted); margin-bottom: 3px; }
.msg.user { background: var(--user); margin-right: auto; border-bottom-left-radius: 4px; }
.msg.admin { background: var(--admin); margin-left: auto; border-bottom-right-radius: 4px; }
.msg .time { font-size: 10px; color: var(--muted); margin-top: 4px; text-align: right; }

/* 输入区 */
.composer { border-top: 1px solid var(--line); padding: 12px; background: var(--panel); display: flex; gap: 10px; }
.composer textarea {
  flex: 1; resize: none; height: 46px; max-height: 140px; border-radius: 10px; border: 1px solid var(--line);
  background: var(--panel2); color: var(--text); padding: 12px; font-size: 14px; outline: none; font-family: inherit;
}
.composer textarea:focus { border-color: var(--primary); }
.icon-btn {
  flex: none; width: 46px; height: 46px; border-radius: 10px; border: 1px solid var(--line);
  background: var(--panel2); color: var(--text); font-size: 20px; cursor: pointer;
  display: flex; align-items: center; justify-content: center; transition: .15s;
}
.icon-btn:hover { border-color: var(--primary); color: var(--primary); }
.msg-img { max-width: 220px; max-height: 260px; border-radius: 10px; display: block; cursor: zoom-in; }

.filter { display: flex; gap: 6px; margin-bottom: 6px; }
.chip { flex: 1; font-size: 12px; padding: 7px; border-radius: 8px; border: 1px solid var(--line); background: var(--panel2); color: var(--muted); cursor: pointer; }
.chip.active { color: #fff; border-color: var(--primary); }

/* 用户侧删除按钮 */
.thread { position: relative; }
.thread-del {
  margin-top: 8px; align-self: flex-end; font-size: 11px; padding: 3px 9px;
  background: transparent; border: 1px solid var(--line); color: var(--muted);
  border-radius: 8px; cursor: pointer; transition: .15s;
}
.thread-del:hover { color: var(--danger); border-color: var(--danger); }

/* 管理端：按用户分组 */
.group { margin-bottom: 14px; }
.group-head {
  display: flex; align-items: center; justify-content: space-between;
  padding: 4px 6px; margin-bottom: 6px;
  font-size: 12px; font-weight: 700; color: var(--text);
  border-left: 3px solid var(--primary); padding-left: 8px;
}
.group-count { font-size: 11px; color: var(--muted); font-weight: 600; background: var(--panel2); padding: 1px 8px; border-radius: 8px; }
.group .thread-list { margin-top: 0; }

/* 管理端：用户管理 */
.user-row {
  display: flex; align-items: center; justify-content: space-between; gap: 10px;
  padding: 10px 12px; border-radius: 12px; background: var(--panel2);
  border: 1px solid var(--line); margin-bottom: 8px;
}
.user-row.banned { border-color: var(--danger); opacity: .85; }
.user-info { min-width: 0; }
.user-name { font-size: 14px; font-weight: 600; }
.user-sub { font-size: 11px; color: var(--muted); margin-top: 2px; }
.btn.danger { background: var(--danger); color: #fff; }
.btn.danger:hover { filter: brightness(1.08); }

.empty.small { padding: 18px 0; font-size: 13px; }

/* 用户管理搜索框 */
.search {
  width: 100%; padding: 9px 12px; border-radius: 10px; border: 1px solid var(--line);
  background: var(--panel2); color: var(--text); font-size: 13px; outline: none; margin-bottom: 10px;
}
.search:focus { border-color: var(--primary); }

/* 移动端 */
@media (max-width: 720px) {
  .layout { flex-direction: column; }
  .sidebar { width: 100%; height: 38%; border-right: none; border-bottom: 1px solid var(--line); }
  .chat { height: 62%; }
}