/* betitled 사이트 틀: 표시(마크), 머리줄, 본문 폭, 로그인 화면 */
/* 마크: 검은 사각형 안의 L자(= "타이틀을 받는 자리") */
.bt-mark { position: relative; display: inline-block; flex: none; width: 22px; height: 22px; background: var(--fg); }
.bt-mark::before, .bt-mark::after { content: ""; position: absolute; background: var(--bg); }
.bt-mark::before { left: 28%; top: 22%; width: 13%; height: 56%; }
.bt-mark::after { left: 28%; top: 65%; width: 44%; height: 13%; }

.bt-boot { display: grid; place-items: center; height: 100vh; }
.bt-boot .bt-mark { width: 40px; height: 40px; animation: bt-pulse 1.1s steps(2, jump-none) infinite; }
@keyframes bt-pulse { 50% { opacity: 0.15; } }

/* 위에 붙은 머리줄 밑으로 스크롤해 들어가지 않게 */
html { scroll-padding-top: 72px; }
.bt-top { position: sticky; top: 0; z-index: 20; display: flex; align-items: center; gap: 12px; height: 56px; padding: 0 max(20px, calc((100vw - 1040px) / 2)); background: color-mix(in srgb, var(--bg) 85%, transparent); backdrop-filter: saturate(0) blur(12px); -webkit-backdrop-filter: saturate(0) blur(12px); border-bottom: 1px solid var(--line); }
.bt-brand { display: inline-flex; align-items: center; gap: 10px; font-weight: 800; font-size: 17px; text-decoration: none; letter-spacing: -0.04em; }
.bt-brand-sub { font: 500 10.5px/1 var(--mono); letter-spacing: 0.08em; text-transform: uppercase; color: var(--muted); padding-left: 10px; border-left: 1px solid var(--border); }
.bt-me { max-width: 50vw; gap: 8px; padding: 0 6px 0 4px; height: 36px; border: 1px solid transparent; }
.bt-me:hover { border-color: var(--line); background: transparent; }
.bt-av { display: inline-grid; place-items: center; width: 26px; height: 26px; background: var(--fg); color: var(--bg); font: 700 12px/1 var(--mono); text-transform: uppercase; flex: none; }
.bt-me-name { overflow: hidden; text-overflow: ellipsis; }
.bt-caret { font-size: 10px; color: var(--muted); }
.page { max-width: 1040px; margin: 0 auto; padding: 48px 20px 20vh; }
.menu-item { display: flex; align-items: center; gap: 8px; width: 100%; padding: 9px 10px; border-radius: var(--r-sm); text-align: left; font-size: 14px; font-weight: 500; }
.menu-item:hover { background: var(--fg); color: var(--bg); }

/* ---------- 로그인·가입: 왼쪽 검은 면 + 오른쪽 폼 ---------- */
.bt-auth { min-height: 100vh; display: grid; grid-template-columns: minmax(0, 1.1fr) minmax(0, 1fr); background: var(--bg); }
.bt-auth-hero { position: relative; display: flex; flex-direction: column; justify-content: space-between; gap: 40px; padding: 40px 48px; background: var(--fg); color: var(--bg); overflow: hidden; }
.bt-auth-hero .bt-mark { background: var(--bg); }
.bt-auth-hero .bt-mark::before, .bt-auth-hero .bt-mark::after { background: var(--fg); }
.bt-auth-hero .eyebrow { color: color-mix(in srgb, var(--bg) 60%, var(--fg)); }
.bt-hero-top { display: flex; align-items: center; gap: 12px; }
.bt-hero-word { margin: 0; font-size: clamp(64px, 11vw, 168px); line-height: 0.86; font-weight: 800; letter-spacing: -0.065em; }
.bt-hero-word span { display: block; color: color-mix(in srgb, var(--bg) 38%, var(--fg)); }
.bt-hero-list { list-style: none; margin: 0; padding: 0; display: grid; grid-template-columns: repeat(3, 1fr); border-top: 1px solid color-mix(in srgb, var(--bg) 30%, var(--fg)); }
.bt-hero-list li { display: flex; flex-direction: column; gap: 6px; padding: 16px 12px 0 0; font-size: 15px; font-weight: 600; letter-spacing: -0.02em; }
.bt-hero-list li + li { padding-left: 14px; border-left: 1px solid color-mix(in srgb, var(--bg) 30%, var(--fg)); }
.bt-hero-list span { font: 500 11px/1 var(--mono); color: color-mix(in srgb, var(--bg) 55%, var(--fg)); }

.bt-auth-main { display: grid; place-items: center; padding: 48px 24px; }
.bt-auth-card { width: min(380px, 100%); display: flex; flex-direction: column; gap: 10px; }
.bt-auth-card h1 { margin: 4px 0 0; font-size: 40px; line-height: 1; font-weight: 800; letter-spacing: -0.05em; }
.bt-auth-card > p { margin: 0; }
.bt-auth-form { display: flex; flex-direction: column; gap: 18px; margin: 24px 0 8px; text-align: left; }
.bt-auth-form label { display: flex; flex-direction: column; gap: 6px; font-size: 12px; font-weight: 600; color: var(--muted); }
.bt-auth-form input { height: 48px; padding: 0 2px; border: 0; border-bottom: 1px solid var(--border); border-radius: 0; background: transparent; color: var(--fg); font: 500 16px var(--font); letter-spacing: -0.01em; text-transform: none; transition: border-color 0.15s; }
.bt-auth-form input:hover { border-bottom-color: var(--muted); }
.bt-auth-form input:focus, .bt-auth-form input:focus-visible { outline: none; border-bottom-color: var(--line) !important; box-shadow: inset 0 -1px 0 var(--line); }
.bt-auth-form .btn.block { margin-top: 8px; }
.bt-auth-err { margin: 0; padding: 10px 12px; border: 1px solid var(--line); font-size: 13px; font-weight: 500; }
.bt-auth-err::before { content: "! "; font-family: var(--mono); font-weight: 700; }
.bt-auth-switch { padding-top: 14px; border-top: 1px solid var(--border); }
.bt-auth-switch a { color: var(--fg); font-weight: 700; }
.bt-auth-note { margin: 0; }

@media (max-width: 860px) {
  .bt-auth { grid-template-columns: 1fr; }
  .bt-auth-hero { padding: 24px 20px 28px; gap: 28px; }
  .bt-hero-word { font-size: clamp(56px, 18vw, 96px); }
  .bt-auth-main { place-items: start center; padding: 36px 20px 64px; }
}
@media (max-width: 640px) {
  .page { padding: 28px 16px 20vh; }
  .bt-top { padding: 0 16px; }
  .bt-brand-sub { display: none; }
  .bt-hero-list li { font-size: 13px; }
}
@media (prefers-reduced-motion: reduce) { .bt-boot .bt-mark { animation: none; } }