/* ===== 版面居中 & 卡片 ===== */
body{
  display:flex;
  justify-content:center;
  align-items:center;
  min-height:100vh;
  background:#f3f5f9;
  font-family:-apple-system,BlinkMacSystemFont,"Segoe UI",Roboto,"Helvetica Neue",Arial,sans-serif;
  margin:0;
}
.box{
  background:#fff;
  padding:40px 32px;
  border-radius:12px;          /* 更大的圆角 */
  box-shadow:0 4px 20px rgba(0,0,0,.08);
  width:360px;                 /* 略宽，输入更舒展 */
  text-align:center;
}

/* ===== 标题 ===== */
.title{
  font-size:24px;
  font-weight:600;
  color:#0070f3;
  margin-bottom:8px;
}
h1{
  font-size:20px;
  color:#333;
  margin:0 0 24px;
}

/* ===== 表单 ===== */
form{
  display:flex;
  flex-direction:column;
  gap:16px;                    /* 统一间距 */
}
input{
  padding:12px 14px;
  border:1px solid #ddd;
  border-radius:6px;
  font-size:15px;
  transition:border .2s;
}
input:focus{
  outline:none;
  border-color:#0070f3;
}
button{
  padding:12px;
  background:#0070f3;
  color:#fff;
  border:none;
  border-radius:6px;
  font-size:15px;
  cursor:pointer;
  transition:background .2s;
}
button:hover{
  background:#0056d3;
}

/* ===== 提示 ===== */
.flash{
  color:#e00;
  font-size:14px;
  margin-bottom:12px;
}