/* ==========================================================
   components/button.css — 버튼 · 텍스트 링크 · 맨 위로 버튼
   .btn + (.btn-brand | .btn-navy | .btn-soft | .btn-line) + (.btn-sm | .btn-lg | .btn-block)
   ========================================================== */

.btn {
  display: inline-flex; align-items: center; justify-content: center; gap: 8px;
  height: 48px; padding: 0 20px; border-radius: 14px;
  font-size: 15px; font-weight: 700; white-space: nowrap;
  transition: transform .12s, box-shadow .2s, background .2s, color .2s;
}
.btn:active { transform: scale(.98); }
.btn .ico { width: 18px; height: 18px; }
.btn[disabled], .btn[aria-disabled="true"] { opacity: .45; pointer-events: none; }

/* 주 행동 — 한 화면에 하나만 */
.btn-brand {
  color: #fff; text-shadow: 0 1px 1px rgba(150, 45, 0, .25);
  background: linear-gradient(135deg, var(--brand-light) 0%, var(--brand) 55%, var(--brand-dark) 100%);
  box-shadow: var(--shadow-brand);
}
.btn-brand:hover { box-shadow: 0 16px 30px -10px rgba(232, 86, 26, .65); }

.btn-navy { color: #fff; background: var(--navy); box-shadow: 0 12px 24px -12px rgba(22, 33, 62, .55); }
.btn-navy:hover { background: var(--navy-hover); }
.btn-soft { background: var(--surface-2); color: var(--ink); }
.btn-soft:hover { background: var(--surface-3); }
.btn-line { background: #fff; color: var(--ink); box-shadow: inset 0 0 0 1.5px var(--line); }
.btn-line:hover { box-shadow: inset 0 0 0 1.5px var(--line-hover); }

.btn-sm { height: 38px; padding: 0 14px; border-radius: 12px; font-size: 14px; }
.btn-lg { height: 52px; border-radius: 16px; font-size: 16px; }
.btn-block { width: 100%; }

/* ---------- 텍스트 링크 ---------- */
.link { display: inline-flex; align-items: center; gap: 4px; min-height: 32px; font-size: 14px; font-weight: 700; color: var(--brand-deep); white-space: nowrap; }
.link:hover { text-decoration: underline; text-underline-offset: 3px; }
.link .ico { width: 16px; height: 16px; }

/* ---------- 맨 위로 ---------- */
.to-top {
  position: fixed; right: 16px; bottom: calc(20px + env(safe-area-inset-bottom)); z-index: 60;
  width: 46px; height: 46px; border-radius: 50%; display: grid; place-items: center;
  background: #fff; color: var(--ink-2); border: 1px solid var(--line);
  box-shadow: 0 10px 24px -10px rgba(29, 36, 51, .35);
  opacity: 0; transform: translateY(12px) scale(.9); pointer-events: none;
  transition: opacity .25s, transform .25s, background .15s;
}
.to-top.show { opacity: 1; transform: none; pointer-events: auto; }
.to-top:hover { background: var(--surface-2); }
@media (min-width: 1024px) {
  .to-top { right: 28px; bottom: calc(28px + env(safe-area-inset-bottom)); width: 50px; height: 50px; }
}