:root{
  --bg:#f6f6f4;--card:#ffffff;--fg:#141416;--mut:#6b6b73;--line:#e6e5e1;--soft:#f0efec;
  --acc:#1d4ed8;--acc-fg:#ffffff;--acc-soft:rgba(29,78,216,.08);--danger:#b42318;--ok:#067647;
  --glow:rgba(29,78,216,.16);--shadow:0 1px 2px rgba(16,16,20,.04),0 12px 32px -12px rgba(16,16,20,.12);
  color-scheme:light;
}
@media (prefers-color-scheme:dark){:root{
  --bg:#0b0c0e;--card:#131417;--fg:#f2f2f3;--mut:#9a9aa3;--line:#25262b;--soft:#1a1b1f;
  --acc:#7aa2ff;--acc-fg:#0b0c0e;--acc-soft:rgba(122,162,255,.10);--danger:#ff8a80;--ok:#5fd39b;
  --glow:rgba(122,162,255,.18);--shadow:0 1px 2px rgba(0,0,0,.3),0 16px 40px -16px rgba(0,0,0,.6);
  color-scheme:dark;
}}
*{box-sizing:border-box}
html,body{margin:0;height:100%}
body{background:var(--bg);color:var(--fg);font:15px/1.55 ui-sans-serif,system-ui,-apple-system,"Pretendard","Apple SD Gothic Neo","Malgun Gothic",sans-serif;
  -webkit-font-smoothing:antialiased;display:grid;place-items:center;min-height:100%;padding:24px 16px;position:relative;overflow-x:hidden}
/* 절제된 빛: 카드 뒤 한 점 */
body::before{content:"";position:fixed;inset:auto;left:50%;top:38%;width:520px;height:520px;transform:translate(-50%,-50%);
  background:radial-gradient(closest-side,var(--glow),transparent 72%);pointer-events:none;filter:blur(6px);opacity:.9}
main{position:relative;width:100%;max-width:380px}
.card{background:var(--card);border:1px solid var(--line);border-radius:16px;padding:28px 24px 24px;box-shadow:var(--shadow)}
.brand{display:flex;align-items:center;gap:10px;margin-bottom:22px}
.brand svg{width:28px;height:28px;flex:none}
.brand b{font-weight:650;letter-spacing:-.01em;font-size:15px}
.brand span{color:var(--mut);font-size:13px}
h1{font-size:20px;line-height:1.3;margin:0 0 6px;letter-spacing:-.02em;font-weight:650}
.lead{margin:0 0 22px;color:var(--mut);font-size:14px}
.lead b{color:var(--fg);font-weight:600;word-break:break-all}
.btn{appearance:none;border:0;width:100%;height:44px;border-radius:10px;font:inherit;font-weight:600;cursor:pointer;display:inline-flex;align-items:center;justify-content:center;gap:8px;
  transition:transform .08s ease,background-color .15s ease,opacity .15s ease}
.btn:active{transform:translateY(1px)}
.btn[disabled]{opacity:.55;cursor:default}
.btn svg{width:18px;height:18px}
.primary{background:var(--fg);color:var(--bg)}
.primary:hover:not([disabled]){opacity:.92}
.ghost{background:transparent;color:var(--fg);border:1px solid var(--line);height:40px;font-weight:550}
.ghost:hover{background:var(--soft)}
.link{appearance:none;border:0;background:none;color:var(--mut);font:inherit;font-size:13px;cursor:pointer;padding:6px 0;text-decoration:underline;text-underline-offset:3px;text-decoration-color:var(--line)}
.link:hover{color:var(--fg)}
.row{display:flex;gap:8px;margin-top:10px}
.stack{display:grid;gap:10px}
.field{display:grid;gap:6px;margin-bottom:12px}
.field label{font-size:13px;color:var(--mut)}
input[type=text]{width:100%;height:42px;border-radius:10px;border:1px solid var(--line);background:var(--card);color:var(--fg);font:inherit;padding:0 12px;outline:none;letter-spacing:.02em}
input[type=text]:focus{border-color:var(--acc);box-shadow:0 0 0 3px var(--acc-soft)}
.msg{min-height:20px;margin:12px 0 0;font-size:13px;color:var(--mut)}
.msg.err{color:var(--danger)}
.msg.ok{color:var(--ok)}
.sep{height:1px;background:var(--line);margin:18px 0}
.foot{margin-top:14px;text-align:center;color:var(--mut);font-size:12px}
.codes{display:grid;grid-template-columns:1fr 1fr;gap:6px;margin:4px 0 14px;padding:12px;border-radius:10px;background:var(--soft);
  font:13px/1.4 ui-monospace,SFMono-Regular,Menlo,Consolas,monospace;letter-spacing:.02em}
.codes span{padding:4px 6px;border-radius:6px;background:var(--card);border:1px solid var(--line);text-align:center;user-select:all}
.check{display:flex;gap:8px;align-items:flex-start;font-size:13px;color:var(--mut);margin:0 0 14px;cursor:pointer}
.check input{margin-top:3px;accent-color:var(--fg)}
.who{display:flex;align-items:center;gap:10px;padding:12px;border:1px solid var(--line);border-radius:10px;margin-bottom:14px}
.who i{width:32px;height:32px;border-radius:50%;background:var(--acc-soft);color:var(--acc);display:grid;place-items:center;font-style:normal;font-weight:650}
.spin{width:16px;height:16px;border-radius:50%;border:2px solid currentColor;border-right-color:transparent;animation:r .8s linear infinite}
@keyframes r{to{transform:rotate(360deg)}}
[hidden]{display:none!important}
.field.tight{margin:6px 0 0}
.lead.flush{margin:0}
.row.below{margin:0 0 14px}
.as-link{text-decoration:none}
@media (max-width:420px){.card{padding:24px 18px 20px}.codes{grid-template-columns:1fr}}
@media (prefers-reduced-motion:reduce){.spin{animation-duration:2s}.btn{transition:none}}