/* ===== iMessage / iOS 风格 · 反馈墙 ===== */
*{box-sizing:border-box}
:root{
  --bg:#f2f2f7;--card:#fff;--txt:#000;--sub:#8a8a8e;--sep:rgba(60,60,67,.18);
  --blue:#007aff;--fill:rgba(120,120,128,.12);--shadow:0 1px 2px rgba(0,0,0,.05);
}
@media (prefers-color-scheme:dark){
  :root{
    --bg:#000;--card:#1c1c1e;--txt:#fff;--sub:#98989f;--sep:rgba(84,84,88,.5);
    --blue:#0a84ff;--fill:rgba(120,120,128,.24);--shadow:0 1px 2px rgba(0,0,0,.4);
  }
}
html,body{margin:0;background:var(--bg);color:var(--txt)}
body{
  font-family:-apple-system,BlinkMacSystemFont,"SF Pro Text","PingFang SC","Hiragino Sans GB","Microsoft YaHei",system-ui,sans-serif;
  font-size:16px;line-height:1.5;-webkit-font-smoothing:antialiased;-webkit-tap-highlight-color:transparent;
}
a{color:var(--blue);text-decoration:none}
button,input,select,textarea{font-family:inherit}
button{cursor:pointer;-webkit-tap-highlight-color:transparent}

/* ---------- 顶栏 ---------- */
.topbar{
  position:sticky;top:0;z-index:20;
  display:flex;align-items:center;gap:10px;
  padding:10px 16px;padding-top:calc(10px + env(safe-area-inset-top));
  background:rgba(249,249,249,.92);color:var(--txt);
  -webkit-backdrop-filter:saturate(180%) blur(22px);backdrop-filter:saturate(180%) blur(22px);
  border-bottom:.5px solid var(--sep);
}
@media (prefers-color-scheme:dark){
  .topbar{background:rgba(28,28,30,.9)}
}
.brand{display:flex;align-items:center;gap:9px;color:inherit;text-decoration:none;min-width:0}
.logo{
  width:30px;height:30px;border-radius:9px;flex:none;display:grid;place-items:center;
  background:linear-gradient(180deg,#33adff,#0a7dff);color:#fff;font-size:14px;font-weight:600;
}
.brand-txt{min-width:0}
.brand-txt b{display:block;font-size:15px;font-weight:600;letter-spacing:-.2px;white-space:nowrap;overflow:hidden;text-overflow:ellipsis}
.brand-txt i{display:block;font-style:normal;font-size:11px;color:var(--sub);margin-top:1px}
.topnav{margin-left:auto;display:flex;align-items:center;gap:4px;flex:none}
.ghost-btn{
  border:0;background:none;color:var(--blue);font-size:15px;letter-spacing:-.2px;
  padding:8px 10px;border-radius:10px;text-decoration:none;transition:background .14s;
}
.ghost-btn:active{background:var(--fill)}
.solid-btn{
  border:0;background:var(--blue);color:#fff;font-size:15px;font-weight:600;letter-spacing:-.2px;
  padding:7px 14px;border-radius:10px;transition:transform .12s,opacity .15s;
}
.solid-btn:active{transform:scale(.96);opacity:.9}
.solid-btn.big{padding:9px 18px;border-radius:10px;font-size:15px}

/* ---------- 容器 ---------- */
.wrap{max-width:680px;margin:0 auto;padding:16px 16px 0}

/* ---------- Hero ---------- */
.hero{padding:6px 2px 18px}
.eyebrow{
  font-size:11px;font-weight:600;letter-spacing:.8px;text-transform:uppercase;
  color:var(--sub);margin:0 0 8px;
}
.hero h1{
  font-size:32px;line-height:1.12;letter-spacing:-1.1px;font-weight:700;
  margin:0 0 10px;color:var(--txt);
}
.hero .sub{font-size:15px;line-height:1.5;color:var(--sub);margin:0 0 14px;letter-spacing:-.1px}
.hero-stats{display:flex;align-items:center;gap:10px;font-size:13px;color:var(--sub)}
.hero-stats b{color:var(--txt);font-size:15px;font-weight:600;font-variant-numeric:tabular-nums}
.dot{width:3px;height:3px;border-radius:50%;background:var(--sub);opacity:.5}

/* ---------- 编辑器 ---------- */
.composer{
  background:var(--card);border-radius:16px;padding:14px;
  box-shadow:var(--shadow);margin-bottom:20px;
}
.composer textarea{
  width:100%;border:0;outline:0;resize:none;background:transparent;
  font-size:16px;line-height:1.45;color:var(--txt);min-height:92px;letter-spacing:-.1px;
}
.composer textarea::placeholder{color:var(--sub)}
.composer-meta{
  display:flex;align-items:center;gap:10px;margin-top:6px;
  padding-top:10px;border-top:.5px solid var(--sep);
}
.cats{display:flex;gap:8px;overflow-x:auto;flex:1;min-width:0;-webkit-overflow-scrolling:touch}
.cats::-webkit-scrollbar{display:none}
.chip{
  border:0;background:var(--fill);color:var(--txt);font-size:13px;letter-spacing:-.1px;
  padding:6px 12px;border-radius:999px;white-space:nowrap;transition:.15s;
}
.chip.active{background:var(--blue);color:#fff;font-weight:500}
.chip:active{transform:scale(.96)}
.counter{font-size:12px;color:var(--sub);font-variant-numeric:tabular-nums;flex:none}
.composer-row{display:flex;gap:8px;margin-top:10px;align-items:center}
.composer-row input{
  flex:1;min-width:0;outline:0;color:var(--txt);
  border:.5px solid var(--sep);border-radius:10px;background:var(--fill);
  padding:9px 12px;font-size:15px;transition:border-color .16s;
}
.composer-row input:focus{border-color:var(--blue)}
.composer-row input::placeholder{color:var(--sub)}
.composer-row select{
  outline:0;color:var(--txt);border:.5px solid var(--sep);border-radius:10px;
  background:var(--fill);padding:9px 10px;font-size:15px;flex:none;
}
.tip{font-size:12px;color:var(--sub);margin:10px 0 0;line-height:1.45}
.tip.warn{color:#ff9500}

/* ---------- 排序 / 筛选 ---------- */
.feed-head{display:flex;align-items:center;gap:10px;margin:0 0 12px;flex-wrap:wrap}
.tabs{display:inline-flex;background:var(--fill);border-radius:9px;padding:2px;flex:none}
.tab{
  border:0;background:none;color:var(--txt);font-size:14px;letter-spacing:-.2px;
  padding:6px 15px;border-radius:7px;font-weight:500;transition:.16s;
}
.tab.active{background:var(--card);font-weight:600;box-shadow:0 1px 3px rgba(0,0,0,.14)}
.filters{display:flex;gap:8px;overflow-x:auto;min-width:0;flex:1;-webkit-overflow-scrolling:touch}
.filters::-webkit-scrollbar{display:none}
.filters .chip{font-size:12.5px;padding:5px 11px}

/* ---------- 卡片 ---------- */
.feed{display:flex;flex-direction:column;gap:10px}
.card{
  background:var(--card);border-radius:16px;padding:14px;
  box-shadow:var(--shadow);transition:transform .16s cubic-bezier(.2,.9,.25,1);
}
.card:active{transform:scale(.995)}
.card-top{display:flex;align-items:center;gap:7px;margin-bottom:8px;flex-wrap:wrap}
.cat-tag{
  font-size:11px;font-weight:600;letter-spacing:-.1px;
  padding:3px 8px;border-radius:6px;background:var(--fill);color:var(--sub);
}
.cat-tag.c-食堂宿舍{background:rgba(255,149,0,.15);color:#c25f00}
.cat-tag.c-设施报修{background:rgba(0,122,255,.13);color:#0060df}
.cat-tag.c-心理树洞{background:rgba(175,82,222,.15);color:#8e3fb8}
.cat-tag.c-教学建议{background:rgba(52,199,89,.16);color:#1f8a3b}
.cat-tag.c-校园生活{background:rgba(255,45,85,.13);color:#c9163c}
.cat-tag.c-其他{background:var(--fill);color:var(--sub)}
@media (prefers-color-scheme:dark){
  .cat-tag.c-食堂宿舍{color:#ffb340}
  .cat-tag.c-设施报修{color:#64a8ff}
  .cat-tag.c-心理树洞{color:#c98cf0}
  .cat-tag.c-教学建议{color:#5fd97f}
  .cat-tag.c-校园生活{color:#ff6b8a}
}
.card-time{margin-left:auto;font-size:12px;color:var(--sub);flex:none}
.card-body{
  font-size:16px;line-height:1.48;letter-spacing:-.1px;color:var(--txt);
  margin:0 0 10px;white-space:pre-wrap;word-break:break-word;
}
.card-foot{
  display:flex;align-items:center;gap:10px;
  padding-top:10px;border-top:.5px solid var(--sep);
}
.who{display:flex;align-items:center;gap:6px;font-size:13px;color:var(--sub);min-width:0}
.who>span{overflow:hidden;text-overflow:ellipsis;white-space:nowrap}
.avatar{
  width:22px;height:22px;border-radius:50%;flex:none;display:grid;place-items:center;
  background:linear-gradient(180deg,#33adff,#0a7dff);color:#fff;
  font-size:11px;font-style:normal;font-weight:600;
}
.acts{margin-left:auto;display:flex;gap:6px;flex:none}
.act{
  border:0;background:var(--fill);color:var(--sub);font-size:13px;letter-spacing:-.1px;
  padding:6px 12px;border-radius:999px;display:inline-flex;align-items:center;gap:5px;
  transition:.15s;
}
.act:active{transform:scale(.95)}
.act.like[aria-pressed="true"]{background:rgba(0,122,255,.14);color:var(--blue);font-weight:500}
.act.report:active{background:rgba(255,59,48,.14);color:#ff3b30}

/* ---------- 空态 / 骨架 / 加载更多 ---------- */
.empty{
  text-align:center;color:var(--sub);font-size:14px;
  padding:48px 16px;line-height:1.6;
}
.skeleton{
  height:96px;border-radius:16px;
  background:linear-gradient(100deg,var(--card) 30%,var(--fill) 50%,var(--card) 70%);
  background-size:220% 100%;animation:shimmer 1.3s linear infinite;
}
@keyframes shimmer{from{background-position:130% 0}to{background-position:-30% 0}}
.loadmore{display:flex;justify-content:center;margin:16px 0 0}
.loadmore .ghost-btn{font-size:15px}

/* ---------- 页脚 ---------- */
.foot{
  margin:28px 2px 40px;font-size:13px;line-height:1.6;color:var(--sub);
  padding-bottom:env(safe-area-inset-bottom);
}
.foot-title{font-weight:600;color:var(--txt);font-size:14px;margin:0 0 8px;letter-spacing:-.2px}
.foot ul{margin:0;padding-left:18px}
.foot li{margin-bottom:6px}
.foot-bottom{font-size:12px;margin-top:16px;color:var(--sub);line-height:1.8}
.foot a{color:var(--blue)}

/* ---------- Toast ---------- */
.toast{
  position:fixed;left:50%;bottom:32px;transform:translate(-50%,14px);opacity:0;pointer-events:none;
  background:rgba(28,28,30,.9);color:#fff;font-size:14px;padding:11px 18px;border-radius:14px;
  -webkit-backdrop-filter:blur(14px);backdrop-filter:blur(14px);
  transition:.24s cubic-bezier(.2,.9,.25,1);z-index:60;max-width:86vw;text-align:center;
  box-shadow:0 10px 30px rgba(0,0,0,.24);
}
.toast.show{opacity:1;transform:translate(-50%,0)}

@media (prefers-reduced-motion: reduce){
  .skeleton{animation:none}
  .card,.toast,.chip,.act,.solid-btn{transition:none}
}