* { box-sizing: border-box; margin: 0; padding: 0; }

body {
  font-family: "Segoe UI", "Microsoft YaHei", system-ui, sans-serif;
  background: linear-gradient(160deg, #1e2a4a 0%, #2c3e66 55%, #35507a 100%);
  min-height: 100vh;
  color: #223;
  padding: 24px 12px 48px;
}

.wrap {
  max-width: 640px;
  margin: 0 auto;
}

header { text-align: center; color: #fff; margin-bottom: 22px; }
header h1 { font-size: 30px; letter-spacing: 1px; }
header .sub { margin-top: 8px; font-size: 14px; opacity: .85; line-height: 1.8; }
code {
  background: rgba(255,255,255,.18);
  padding: 1px 7px;
  border-radius: 5px;
  font-size: .92em;
  color: #ffe9a8;
}

.card {
  background: #fff;
  border-radius: 14px;
  padding: 20px 22px;
  margin-bottom: 18px;
  box-shadow: 0 10px 28px rgba(0,0,0,.18);
}
.card h2 { font-size: 17px; margin-bottom: 14px; color: #2c3e66; }

label { display: block; margin-bottom: 12px; font-size: 14px; color: #555; }
label input,
label textarea {
  display: block;
  width: 100%;
  margin-top: 6px;
  padding: 10px 12px;
  border: 1px solid #ccd3e0;
  border-radius: 8px;
  font-size: 15px;
  font-family: inherit;
  resize: vertical;
}
label input:focus,
label textarea:focus { outline: 2px solid #4f78c9; border-color: transparent; }

button {
  background: #2c3e66;
  color: #fff;
  border: 0;
  padding: 10px 26px;
  border-radius: 8px;
  font-size: 15px;
  cursor: pointer;
  transition: background .2s;
}
button:hover { background: #4067a8; }

ul { list-style: none; }
.msg {
  border: 1px solid #e3e8f2;
  border-radius: 10px;
  padding: 12px 14px;
  margin-bottom: 10px;
}
.msg .head {
  display: flex;
  justify-content: space-between;
  margin-bottom: 6px;
  font-size: 14px;
}
.msg .head b { color: #2c3e66; }
.msg .head time { color: #98a2b3; font-size: 12px; }
.msg .body {
  font-size: 15px;
  line-height: 1.6;
  white-space: pre-wrap;
  word-break: break-word;
}

.empty { color: #98a2b3; text-align: center; padding: 10px 0; font-size: 14px; }
.tip { text-align: center; color: rgba(255,255,255,.7); font-size: 13px; margin-top: 6px; }
.tip code { background: rgba(255,255,255,.12); color: #cfe0ff; }