:root{
  --bg:#fff;
  --bg-pure:#fff;
  --text:rgba(0,0,0,.9);
  --text-2:rgba(0,0,0,.6);
  --text-3:rgba(0,0,0,.45);
  --sep:rgba(0,0,0,.13);
  --hover:rgba(0,0,0,.05);
  --km-blue:#1783ff;
  --shadow:0 4px 12px rgba(0,0,0,.03),0 5px 16px -4px rgba(0,0,0,.07);
  --font:-apple-system,BlinkMacSystemFont,"Segoe UI",system-ui,Roboto,"PingFang SC","Source Han Sans SC","Microsoft YaHei UI","Microsoft YaHei","Noto Sans CJK SC",sans-serif,Arial;
}
*{box-sizing:border-box}
html,body{height:100%;margin:0}
body{font-family:var(--font);background:var(--bg);color:var(--text);font-size:14px;-webkit-font-smoothing:antialiased;overflow:hidden}
button{font:inherit;color:inherit;background:none;border:0;cursor:pointer;padding:0}
a{color:inherit;text-decoration:none}
svg{display:block;flex:0 0 auto}
::selection{background:#1783ff33}

.app{display:grid;grid-template-columns:240px 1fr;height:100vh;transition:grid-template-columns .25s ease}
.app.collapsed{grid-template-columns:0 1fr}

/* ---------- Sidebar ---------- */
.sidebar{
  background:#fbfaf9;
  border-right:1px solid var(--sep);
  min-width:0;
  display:flex;flex-direction:column;
  overflow:hidden;
}
.side-head{display:flex;align-items:center;justify-content:space-between;padding:12px 10px 8px;height:52px}
.brand{display:flex;align-items:center;gap:8px}
.brand .k{width:24px;height:24px;border-radius:8px;background:#111;color:#fff;display:flex;align-items:center;justify-content:center;font-weight:800;font-size:14px;letter-spacing:-.02em}
.brand .name{font-weight:700;font-size:16px;letter-spacing:-.01em;color:var(--text)}
.icon-btn{width:28px;height:28px;border-radius:8px;display:flex;align-items:center;justify-content:center;color:rgba(0,0,0,.7);position:relative}
.icon-btn .icon-hover{display:none}
.icon-btn:hover{background:var(--hover)}
.icon-btn:hover .icon-default{display:none}
.icon-btn:hover .icon-hover{display:block}

.nav{overflow-y:auto;padding:2px 8px;display:flex;flex-direction:column;gap:1px}
.nav-item{display:flex;align-items:center;gap:10px;padding:8px 10px;border-radius:8px;font-size:14px;line-height:25px;color:var(--text);white-space:nowrap}
.nav-item:hover{background:var(--hover)}
.nav-item svg{width:16px;height:16px;color:rgba(0,0,0,.75)}
.nav-item .beta{font-size:10px;color:var(--km-blue);background:#e0eaff;padding:1px 5px;border-radius:4px;margin-left:2px}

/* primary CTA: 在线AI辨证 */
.nav-cta{display:flex;align-items:center;gap:10px;width:calc(100% - 20px);margin:4px 10px 10px;padding:11px 12px;border:1px solid #C9E2F2;border-radius:10px;background:#EAF4FB;color:#185FA5;font-size:14px;font-weight:500;cursor:pointer;text-align:left;transition:background .15s}
.nav-cta:hover{background:#D8EBF7}
.nav-cta svg{width:18px;height:18px;color:#185FA5;flex:0 0 auto}
.nav-cta .cta-text{flex:1;line-height:1.2}
.nav-cta .cta-hint{font-size:11px;color:rgba(24,95,165,.7)}

/* grouped nav */
.nav-group{margin:4px 0}
.nav-label{font-size:11px;color:var(--text-3);padding:10px 12px 4px;letter-spacing:.04em}
.nav-group .nav-item{margin:0 10px;padding:8px 12px}
.recent-item{display:flex;align-items:center;gap:8px;margin:0 10px;padding:7px 12px;border-radius:8px;font-size:13px;color:var(--text-2);text-decoration:none;transition:background .15s}
.recent-item:hover{background:var(--hover);color:var(--text)}
.recent-item .dot{width:6px;height:6px;border-radius:50%;background:var(--km-blue);flex:0 0 auto}
.recent-item .time{margin-left:auto;font-size:11px;color:var(--text-3);white-space:nowrap}

.side-foot{margin-top:auto;border-top:1px solid var(--sep);padding:8px;display:flex;align-items:center;justify-content:space-between}
.login{display:flex;align-items:center;gap:8px;font-size:13px;padding:6px 8px;border-radius:8px}
.login:hover{background:var(--hover)}
.login .avatar{width:22px;height:22px;border-radius:50%;background:#e6e2d9;display:flex;align-items:center;justify-content:center}
.login .arrow{margin-left:auto;color:var(--text-3)}

/* collapsed */
.app.collapsed .sidebar{border-right:0}
.app.collapsed .brand .name,
.app.collapsed .nav,
.app.collapsed .login .label,
.app.collapsed .login .arrow{display:none}
.app.collapsed .side-foot{justify-content:center}

/* toast */
.toast{position:fixed;left:50%;bottom:120px;transform:translateX(-50%) translateY(10px);background:#111;color:#fff;padding:10px 16px;border-radius:10px;font-size:13px;opacity:0;transition:opacity .25s,transform .25s;z-index:100;pointer-events:none;box-shadow:0 8px 24px rgba(0,0,0,.18)}
.toast.show{opacity:1;transform:translateX(-50%) translateY(0)}

/* ---------- Main ---------- */
.main{position:relative;display:flex;flex-direction:column;overflow:hidden}

/* 共享头部：logo + 站名（左） + 展开按钮（右），由 assets/js/header.js 注入 */
.page-header{position:absolute;top:0;left:0;right:0;height:52px;display:flex;align-items:center;justify-content:space-between;padding:0 16px;z-index:20}
.page-header .h-left{display:flex;align-items:center;gap:18px}
.page-header .h-brand{display:flex;align-items:center;gap:8px}
.page-header .h-k{width:24px;height:24px;border-radius:8px;background:#111;color:#fff;display:flex;align-items:center;justify-content:center;font-weight:800;font-size:14px;letter-spacing:-.02em}
.page-header .h-name{font-weight:700;font-size:16px;letter-spacing:-.01em;color:var(--text)}
.page-header .h-blue{color:var(--km-blue)}
.page-header .h-login{display:flex;align-items:center;padding:7px 14px;border-radius:8px;font-size:14px;color:var(--text)}
.page-header .h-login:hover{background:var(--hover)}

.expand-tab{
  width:28px;height:28px;border-radius:8px;
  display:none;align-items:center;justify-content:center;
  background:transparent;border:1px solid transparent;color:rgba(0,0,0,.75);
  cursor:pointer;transition:background .15s;
}
.expand-tab:hover{background:#eaeaea}
.expand-tab svg{width:22px;height:22px}
.expand-tab .icon-hover{display:none}
.expand-tab:hover .icon-default{display:none}
.expand-tab:hover .icon-hover{display:block}
.app.collapsed .expand-tab{display:flex}

/* 宽屏、导航展开时隐藏头部品牌（侧栏已显示 logo+站名，避免重复） */
@media(min-width:768px){
  .app:not(.collapsed) .h-brand{display:none}
}

/* footer (homepage: absolute over stage) */
.footer{position:absolute;left:50%;bottom:15px;transform:translateX(-50%);display:flex;flex-direction:column;gap:4px;align-items:center;justify-content:center;font-size:12px;color:var(--text-3);width:min(820px,92%);text-align:center}
.footer a:hover{color:var(--text)}
.footer .links{display:flex;flex-wrap:wrap;gap:6px 14px;align-items:center;justify-content:center}
.footer .links a{color:var(--text-3);text-decoration:none}
.footer .links a:hover{color:var(--text)}

/* drawer mask (mobile sidebar) */
.drawer-mask{display:none;position:fixed;inset:0;background:rgba(0,0,0,.35);z-index:90}

@media(max-width:767px){
  /* 移动端：取消所有高度约束，整页随文档自然滚动（避免 Edge/手机端拉不动） */
  html,body{overflow:auto;height:auto;-webkit-text-size-adjust:100%}
  .app,.app.collapsed{display:block;height:auto;min-height:100vh}
  .sidebar{position:fixed;left:0;top:0;bottom:0;width:260px;transform:translateX(-100%);z-index:100;transition:transform .25s ease;border-right:0}
  .app.open .sidebar{transform:translateX(0)}
  .app.open .drawer-mask{display:block}
  .expand-tab{display:flex !important}
  .page-header .h-brand{display:flex}
  .main{display:block;width:100%;height:auto;min-height:auto;overflow:visible}
  .page{display:block;height:auto;min-height:auto;flex:none;overflow:visible}
  .page-header{position:fixed;top:0;left:0;right:0;padding:0 16px;background:var(--bg);border-bottom:1px solid var(--sep)}
  .footer{bottom:12px;font-size:11px}
}