:root {
  --bg: #f6f7f9;
  --card: #ffffff;
  --border: #e2e8f0;
  --text: #1a202c;
  --muted: #718096;
  --accent: #3b82f6;
}

* { box-sizing: border-box; }

body {
  margin: 0;
  font-family: 'Microsoft YaHei', system-ui, -apple-system, sans-serif;
  background: var(--bg);
  color: var(--text);
}

header {
  position: sticky;
  top: 0;
  background: #fff;
  border-bottom: 1px solid var(--border);
  padding: 12px 20px;
  display: flex;
  align-items: center;
  justify-content: space-between;
}

h1 { font-size: 18px; margin: 0; }

.actions { display: flex; align-items: center; gap: 12px; }
.status { color: var(--muted); font-size: 13px; }

button {
  background: var(--accent);
  color: #fff;
  border: 0;
  border-radius: 6px;
  padding: 8px 16px;
  font-size: 14px;
  cursor: pointer;
}
button:disabled { opacity: 0.6; cursor: default; }

main { max-width: 760px; margin: 16px auto; padding: 0 16px; }

.list { display: flex; flex-direction: column; gap: 10px; }

.item {
  background: var(--card);
  border: 1px solid var(--border);
  border-radius: 10px;
  padding: 12px 16px;
}

.head { display: flex; justify-content: space-between; align-items: baseline; margin-bottom: 6px; }
.sender { font-weight: 600; }
.time { color: var(--muted); font-size: 12px; }

.content {
  white-space: pre-wrap;
  word-break: break-all;
  line-height: 1.6;
}

.empty { text-align: center; color: var(--muted); padding: 40px 0; }