* { box-sizing: border-box; }
html { background: #fff; }
body { max-width: 640px; margin: 0 auto; color: #000; background: #fff; font: 14px "Microsoft YaHei", sans-serif; }
.help-header { position: fixed; z-index: 2; top: 0; left: 50%; width: 100%; max-width: 640px; height: 44px; transform: translateX(-50%); background: #fff; }
.help-header h1 { margin: 0; font-size: 16px; font-weight: 700; line-height: 44px; text-align: center; }
.help-back { position: absolute; top: 0; left: 0; width: 44px; height: 44px; }
.help-back::before { position: absolute; top: 15px; left: 16px; width: 12px; height: 12px; border-top: 1px solid #000; border-left: 1px solid #000; content: ""; transform: rotate(-45deg); }
.help-tabs { position: fixed; z-index: 1; top: 44px; left: 50%; display: flex; width: 100%; max-width: 640px; height: 43px; transform: translateX(-50%); border-top: 1px solid #d8dbe6; background: #fff; }
.help-tabs button { position: relative; flex: 1; height: 38px; padding: 0; border: 0; background: transparent; color: #303133; font: 700 12px/43px "Microsoft YaHei", sans-serif; text-align: center; cursor: pointer; }
.help-tabs button[aria-selected="true"]::after { position: absolute; right: 22.5%; bottom: 0; left: 22.5%; height: 4px; background: #3d7eff; content: ""; }
.help-content { padding: 5px; margin-top: 89px; }
.help-steps { margin: 0; padding: 0; list-style: none; }
.help-steps p { margin: 0; line-height: 32px; }
.help-steps img { display: inline-block; width: 320px; max-width: 100%; height: 240px; object-fit: contain; vertical-align: baseline; }
[hidden] { display: none !important; }