* { box-sizing: border-box; }
body {
    margin: 0;
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "PingFang SC", "Microsoft YaHei", sans-serif;
    background: linear-gradient(160deg, #eef4ff 0%, #f8fafc 100%);
    color: #1f2937;
}
.wrap { min-height: 100vh; display: flex; align-items: center; justify-content: center; padding: 24px; }
.card {
    width: 100%; max-width: 480px; background: #fff; border-radius: 16px;
    padding: 28px; box-shadow: 0 10px 30px rgba(15, 23, 42, 0.08);
}
h1 { margin: 0 0 8px; font-size: 22px; }
.desc { margin: 0 0 20px; color: #6b7280; line-height: 1.6; font-size: 14px; }
label { display: block; margin-bottom: 14px; font-size: 14px; color: #374151; }
input {
    width: 100%; margin-top: 6px; padding: 12px 14px;
    border: 1px solid #d1d5db; border-radius: 10px; font-size: 16px;
}
button {
    width: 100%; border: 0; border-radius: 10px; padding: 14px;
    font-size: 16px; font-weight: 600; color: #fff; background: #2563eb; cursor: pointer;
}
.tip {
    margin-top: 16px; padding: 12px 14px; border-radius: 10px;
    font-size: 13px; background: #f3f4f6; color: #4b5563;
}
.tip.ok { background: #ecfdf5; color: #047857; }
.desc.err { color: #b91c1c; }
.result p { margin: 8px 0; font-size: 15px; }
.back { display: inline-block; margin-top: 20px; color: #2563eb; text-decoration: none; }