:root{--green: #22c55e;--green-soft: rgba(34, 197, 94, .14)}*{box-sizing:border-box;margin:0;padding:0}body{font-family:var(--font-main);background:var(--bg);color:var(--text);min-height:100vh;-webkit-font-smoothing:antialiased}.wrap{max-width:520px;margin:0 auto;padding:28px 18px 48px;min-height:100vh;display:flex;flex-direction:column}.back{display:inline-flex;align-items:center;gap:6px;padding:8px 14px;border-radius:var(--ui-radius-pill);border:1px solid var(--border-strong);background:var(--surface-2);color:var(--text);text-decoration:none;font-size:13px;font-weight:600;align-self:flex-start;margin-bottom:22px}header{text-align:center;margin-bottom:26px}.logo-wrap{width:64px;height:64px;margin:0 auto 16px;border-radius:var(--ui-radius-lg);background:#fff;display:grid;place-items:center;box-shadow:none;overflow:hidden}.logo-wrap img{width:54px;height:54px;object-fit:contain;display:block}h1{font-size:25px;font-weight:600;letter-spacing:-.01em;margin-bottom:8px}.subtitle{color:var(--text-dim);font-size:14.5px}#system-selection{display:grid;grid-template-columns:1fr 1fr;gap:12px;margin-top:8px}.selection-card{background:linear-gradient(180deg,var(--surface-2),var(--surface));border:1px solid var(--border);border-radius:var(--ui-radius-lg);padding:26px 14px;text-align:center;cursor:pointer;transition:transform .18s cubic-bezier(.2,.8,.2,1),border-color .18s ease,background .18s ease;display:flex;flex-direction:column;align-items:center;gap:12px;box-shadow:none;text-decoration:none;color:inherit}.selection-card:hover{transform:translateY(-3px);border-color:var(--border-strong);background:linear-gradient(180deg,var(--surface-2),var(--surface-2))}.selection-card:active{transform:scale(.97)}.selection-card.android:hover{border-color:#4285f480}.selection-card.ios:hover{border-color:#fff6}.os-icon-large{width:52px;height:52px;display:grid;place-items:center;background:#ffffff0f;border-radius:var(--ui-radius-lg)}.selection-card span{font-weight:600;font-size:15px}.selection-card .selection-sub{font-size:12.5px;font-weight:500;color:var(--text-dim);margin-top:-6px}.btn-play-store{display:flex;align-items:center;justify-content:center;gap:10px;width:100%;padding:13px 18px;background:#1a73e8;color:#fff;font-size:14.5px;font-weight:600;border-radius:var(--ui-radius-lg);text-decoration:none;transition:background .18s ease,transform .18s ease;box-sizing:border-box;margin-top:14px}.btn-play-store:hover{background:#1557b0;transform:translateY(-1px);color:#fff}.instruction-section{display:none}.instruction-section.active{display:block;animation:slide-in .35s cubic-bezier(.2,.8,.2,1) both}@keyframes slide-in{0%{opacity:0;transform:translateY(12px)}to{opacity:1;transform:translateY(0)}}.section-card{background:linear-gradient(180deg,var(--surface-2),var(--surface));border:1px solid var(--border);border-radius:var(--ui-radius-lg);padding:20px;margin-bottom:16px}.section-header{display:flex;align-items:center;justify-content:space-between;margin-bottom:18px;gap:10px}.section-header .os-name{font-weight:600;font-size:15px;display:inline-flex;align-items:center;gap:8px}.section-header .os-name .dot{width:8px;height:8px;border-radius:50%;background:currentColor}#android-instruction .os-name{color:var(--green)}.btn-change-os{background:var(--surface-2);border:1px solid var(--border-strong);color:var(--text-dim);padding:7px 12px;border-radius:var(--ui-radius-pill);font-size:12px;font-weight:600;cursor:pointer}.btn-change-os:hover{background:#ffffff1a}.note{display:flex;gap:10px;align-items:flex-start;padding:12px 14px;border-radius:var(--ui-radius-lg);background:var(--accent-soft);border:1px solid rgba(215,255,224,.35);font-size:13px;line-height:1.5;color:#ffffffe0;margin-bottom:18px}.note svg{flex:0 0 auto;margin-top:1px;color:var(--ui-accent)}.step{margin-bottom:22px}.step:last-child{margin-bottom:0}.step-header{display:flex;gap:10px;align-items:center;margin-bottom:10px}.step-num{width:24px;height:24px;flex:0 0 auto;background:var(--ui-accent);box-shadow:none;border-radius:50%;display:grid;place-items:center;font-size:12px;font-weight:600}.step-title{font-weight:600;font-size:14.5px;line-height:1.35}.step-desc{font-size:13px;color:var(--text-dim);line-height:1.5;margin:6px 0 12px 34px}.step-img{width:calc(100% - 34px);margin-left:34px;border-radius:var(--ui-radius-lg);border:1px solid var(--border);overflow:hidden;background:#101010;box-shadow:none}.step-img img{width:100%;display:block}.highlight{color:#fff;background:#ffffff24;padding:2px 7px;border-radius:var(--ui-radius);font-weight:700}.btn-back{display:flex;align-items:center;justify-content:center;gap:8px;color:var(--text-faint);text-decoration:none;font-size:13.5px;font-weight:500;margin-top:24px;padding:10px}.btn-back:hover{color:var(--text-dim)}