/* =========================================================
   KERD 플랫폼 소개(랜딩) — Figma 스토리보드(27:493) 기반
   common.css 다음에 로드. 톤: 신뢰·전문성·절제 (블루+화이트)
   ========================================================= */

/* ---------- 앵커 내비게이션 (스크롤 스파이) ---------- */
.anchor-nav { position: sticky; top: 0; z-index: 40; background: rgba(255,255,255,.92);
  backdrop-filter: blur(8px); border-bottom: 1px solid var(--line); }
.anchor-nav__in { max-width: var(--wrap); margin: 0 auto; padding: 0 var(--pad-x);
  display: flex; align-items: center; gap: 4px; height: 52px; }
.anchor-nav__in > a { padding: 6px 14px; border-radius: 18px; font-size: var(--fs-14);
  color: var(--ink-2); transition: all .15s; }
.anchor-nav__in > a:hover { background: var(--bg-2); }
.anchor-nav__in > a.is-active { background: var(--navy); color: #fff; font-weight: 600; }
.anchor-nav__cta { margin-left: auto; display: flex; gap: 8px; }
.anchor-nav__cta .btn { padding: 7px 14px; font-size: 13px; }
.anchor-nav__cta .btn--primary { color: #fff; }

/* ---------- 공통 섹션 ---------- */
.sec { padding: 88px 0; }
.sec__label { display: inline-block; color: var(--blue); font-weight: 700;
  font-size: var(--fs-14); letter-spacing: .08em; margin-bottom: 12px; }
.sec__title { font-size: 32px; font-weight: 800; line-height: 1.35; letter-spacing: -0.02em; }
.sec__title .accent { color: var(--blue); }
.sec__desc { color: var(--ink-2); font-size: var(--fs-16); margin-top: 14px; max-width: 760px; }

/* ---------- Hero (중앙 정렬 · 축소형) ---------- */
.hero { position: relative; overflow: hidden; color: #fff; text-align: center;
  background: linear-gradient(165deg, #16203f 0%, #1e2f66 55%, #2a4197 100%); }
.hero__bg { position: absolute; inset: 0; opacity: .65; width: 100%; height: 100%; }
.hero__in { position: relative; z-index: 1; max-width: 980px; margin: 0 auto;
  padding: 128px var(--pad-x) 112px; }
.hero__title { font-size: 54px; font-weight: 800; line-height: 1.3; letter-spacing: -0.02em; }
.hero__sub { margin-top: 20px; font-size: var(--fs-20); color: rgba(255,255,255,.8); }

/* 지표 (CTA 위) */
.hero__stats { margin: 48px auto 0; display: flex; justify-content: center; gap: 72px; flex-wrap: wrap; }
.hero__stats .stat { text-align: left; }
.hero__stats .stat b { display: block; font-size: 34px; font-weight: 800; line-height: 1.2; }
.hero__stats .stat span { font-size: var(--fs-14); color: rgba(255,255,255,.65); }

/* CTA (지표 아래) */
.hero__cta { margin-top: 44px; display: flex; gap: 14px; justify-content: center; flex-wrap: wrap; }
.btn--hero { padding: 15px 36px; font-size: var(--fs-16); font-weight: 700; border-radius: 8px; }
.btn--hero.primary { background: var(--blue); color: #fff; border: 0; }
.btn--hero.primary:hover { background: #0f4fe0; }
.btn--hero.ghost { background: rgba(255,255,255,.08); color: #fff; border: 1px solid rgba(255,255,255,.45); }
.btn--hero.ghost:hover { background: rgba(255,255,255,.16); }
@media (max-width: 640px) {
  .hero__title { font-size: 32px; }
  .hero__in { padding: 72px var(--pad-x) 64px; }
  .hero__stats { gap: 28px; }
}

/* ---------- What is KERD ---------- */
.about-sec { background: #fff; }
.trust { margin-top: 44px; display: grid; grid-template-columns: repeat(3,1fr); gap: 20px; }
.trust .t-card { border: 1px solid var(--line); border-radius: 12px; padding: 26px; background: #fff; }
.trust .t-card .head { display: flex; align-items: center; gap: 12px; margin-bottom: 12px; }
.trust .t-card .ico { width: 44px; height: 44px; border-radius: 10px; background: var(--blue-weak);
  color: var(--blue); display: flex; align-items: center; justify-content: center;
  font-size: 20px; flex: none; }
.trust .t-card h3 { font-size: var(--fs-18); }
.trust .t-card p { color: var(--ink-2); font-size: var(--fs-14); line-height: 1.7; }
@media (max-width: 900px) { .trust { grid-template-columns: 1fr; } }

/* 학술도서 표지 스트립 */
.books { margin-top: 56px; background: var(--blue-weak); border-radius: 16px; padding: 40px; }
.books h3 { font-size: var(--fs-20); }
.books p { color: var(--ink-2); font-size: var(--fs-14); margin-top: 6px; }
.books__strip { margin-top: 24px; overflow: hidden; padding-bottom: 8px;
  -webkit-mask-image: linear-gradient(90deg, transparent 0, #000 5%, #000 95%, transparent 100%);
          mask-image: linear-gradient(90deg, transparent 0, #000 5%, #000 95%, transparent 100%); }
.books__track { --book-gap: 14px; display: flex; gap: var(--book-gap); width: max-content;
  animation: books-roll 40s linear infinite; }
.books__track img { height: 168px; border-radius: 6px; box-shadow: 0 2px 10px rgba(15,23,42,.16); flex: none; }
@keyframes books-roll {
  from { transform: translateX(0); }
  to   { transform: translateX(calc(-50% - var(--book-gap) / 2)); }
}
@media (prefers-reduced-motion: reduce) {
  .books__strip { overflow-x: auto; }
  .books__track { animation: none; }
}

/* ---------- 주요 기능 (STEP 탭 + 목업) ---------- */
.feat-sec { background: #f8fafc; }

/* STEP 스텝퍼 — 원형 노드 + 연결선 (박스 없음) */
.step-tabs { margin-top: 48px; display: grid; grid-template-columns: repeat(4, 1fr); }
.step-tab { background: none; border: 0; position: relative; text-align: center;
  cursor: pointer; padding: 0 12px; }
/* 동그라미 위 STEP 텍스트 */
.step-tab .sn { display: block; height: 18px; font-size: var(--fs-12); font-weight: 800;
  letter-spacing: .08em; color: #b6bcc6; margin-bottom: 10px; transition: color .2s; }
.step-tab.is-active .sn, .step-tab.is-done .sn { color: var(--blue); }
/* 연결선 (마지막 노드 제외, 원 중심 높이 = sn 18 + 여백 10 + 원 반지름 10 = 38px) */
.step-tab:not(:last-child)::before { content: ""; position: absolute; top: 37px;
  left: calc(50% + 16px); right: calc(-50% + 16px); height: 2px;
  background: #e5e7eb; border-radius: 1px; transition: background .2s; }
.step-tab.is-done:not(:last-child)::before { background: var(--blue); }
/* 원형 노드 */
.step-tab .node { display: block; width: 20px; height: 20px; margin: 0 auto 14px;
  border-radius: 50%; border: 2px solid #d1d5db; background: #fff;
  position: relative; z-index: 1; transition: border-color .2s; }
.step-tab .node::after { content: ""; position: absolute; inset: 3px; border-radius: 50%;
  background: #d1d5db; transition: background .2s; }
.step-tab.is-active .node, .step-tab.is-done .node { border-color: var(--blue); }
.step-tab.is-active .node::after, .step-tab.is-done .node::after { background: var(--blue); }
/* 라벨 */
.step-tab .t { display: block; font-size: var(--fs-16); font-weight: 700; color: #9ca3af; transition: color .2s; }
.step-tab .d { display: block; font-size: var(--fs-13, 13px); color: #b6bcc6; margin-top: 4px; transition: color .2s; }
.step-tab.is-active .t, .step-tab.is-done .t { color: var(--ink); }
.step-tab.is-active .d, .step-tab.is-done .d { color: var(--gray); }
.step-tab:hover .t { color: var(--blue); }
@media (max-width: 900px) {
  .step-tabs { grid-template-columns: repeat(2, 1fr); row-gap: 24px; }
  .step-tab:nth-child(2)::before { display: none; } /* 2단 줄바꿈 시 줄 끊김 */
}

/* STEP 행: 목업(좌) + 설명(우) — 화면 중앙 배치 */
.step-row { display: grid; grid-template-columns: minmax(0, 660px) minmax(0, 460px); gap: 64px;
  align-items: center; justify-content: center; padding: 56px 0;
  max-width: 1240px; margin: 0 auto; }
.step-info .s-label { color: var(--blue); font-weight: 700; font-size: var(--fs-14); letter-spacing: .08em; }
.step-info h3 { font-size: 30px; font-weight: 800; margin: 8px 0 12px; }
.step-info > p { color: var(--ink-2); font-size: var(--fs-18); line-height: 1.75; }
.step-info ul { margin-top: 22px; }
.step-info ul li { position: relative; padding: 8px 0 8px 20px; color: var(--ink-2); font-size: var(--fs-16); }
.step-info ul li::before { content: ""; position: absolute; left: 0; top: 18px;
  width: 6px; height: 6px; border-radius: 50%; background: var(--blue); }
@media (max-width: 1100px) { .step-row { grid-template-columns: 1fr; } }

/* ---------- 미니 목업 공통 ---------- */
.mock { background: #fff; border: 1px solid var(--line); border-radius: 12px;
  overflow: hidden; box-shadow: var(--shadow); font-size: 11px; line-height: 1.5; }
.mock * { box-sizing: border-box; }
.mock__nav { background: #1a1f3c; color: #fff; display: flex; align-items: center;
  gap: 24px; padding: 12px 24px 0; }
.mock__nav .logo { font-weight: 700; font-size: 13px; }
.mock__nav .menu { flex: 1; display: flex; gap: 24px; justify-content: center;
  color: rgba(255,255,255,.7); font-size: 11px; }
.mock__search { background: #1a1f3c; display: flex; gap: 8px; padding: 10px 24px 16px; }
.mock__search .q { flex: 1; background: #fff; border-radius: 8px; padding: 8px 12px; color: #161616; }
.mock__search .q.ph { color: #aaa; }
.mock__search .b1 { background: #6366f1; color: #fff; border-radius: 8px; padding: 8px 16px; font-weight: 600; }
.mock__search .b2 { background: #7c3aed; color: #fff; border-radius: 8px; padding: 8px 12px; font-weight: 600; }
.mock__body { padding: 20px 24px; }
.mock .chip { display: inline-block; border: 1px solid var(--line); border-radius: 999px;
  padding: 3px 11px; font-size: 10px; color: var(--ink-2); margin: 0 4px 4px 0; }
.mock .muted { color: #9ca3af; font-size: 10px; }
.mock .link { color: var(--blue); font-weight: 600; }

/* STEP01: AI 분석 패널 */
.mock-ai { background: #fafafa; border: 1px solid var(--line); border-radius: 14px; padding: 17px; }
.mock-ai .cap { color: #9ca3af; font-size: 10px; font-weight: 700; letter-spacing: .5px; }
.mock-ai .sub { color: #4a5565; font-weight: 600; margin-top: 4px; }
.mock-ai .txt { color: #4a5565; margin-top: 8px; }
.mock-ai .rec { margin-top: 12px; }
.mock-ai .rec .no { color: #9ca3af; font-size: 9px; }
.mock-ai .rec .ti { color: var(--blue); font-weight: 600; }
.mock-ai .rec .de { color: #6b7280; font-size: 10px; }

/* STEP02: 논문 상세 */
.mock-paper { display: flex; gap: 24px; }
.mock-paper .main { flex: 1; min-width: 0; }
.mock-paper h4 { font-size: 17px; font-weight: 700; color: #161616; line-height: 1.4; }
.mock-paper .en { color: #6b7280; margin-top: 4px; }
.mock-paper .authors { margin-top: 10px; }
.mock-paper .authors .nm { color: var(--blue); }
.mock-paper .authors .af { color: #9ca3af; }
.mock-paper .meta { margin-top: 14px; display: grid; grid-template-columns: 46px 1fr; row-gap: 4px; }
.mock-paper .meta .k { color: var(--blue); font-weight: 600; }
.mock-paper .meta .v { color: #4a5565; }
.mock-paper .cap { color: #9ca3af; margin-top: 14px; margin-bottom: 5px; }
.mock-paper .abs { color: #4a5565; }
.mock-paper .side { width: 130px; flex: none; display: flex; flex-direction: column; gap: 12px; }
.mock-paper .stats { border: 1px solid var(--line); border-radius: 10px; padding: 13px;
  display: flex; flex-direction: column; gap: 8px; }
.mock-paper .stats .row { display: flex; align-items: center; gap: 6px; }
.mock-paper .stats b { font-size: 13px; display: block; line-height: 1.1; }
.mock-paper .stats small { color: #9ca3af; font-size: 9px; }
.mock-paper .dl { background: #22c55e; color: #fff; border-radius: 10px; text-align: center;
  padding: 10px 0; font-weight: 700; }
.mock-paper .tools { border: 1px solid var(--line); border-radius: 10px; padding: 9px; }
.mock-paper .tools .cap { margin: 0 0 6px; }
.mock-paper .tools div { padding: 4px 6px; color: #4a5565; font-weight: 600; font-size: 10px; }
/* 아이콘 래퍼 — 데스크톱에서는 기존과 동일하게 보이도록 스타일 없음 */
.mock-paper .stats i, .mock-lib .scard i { font-style: normal; }
/* 모바일 전용 요소는 데스크톱에서 숨김 */
.mock-paper .stats .row.m-only { display: none; }
.mock-lib .m-only { display: none; }

/* STEP03: 비슷한 논문 */
.mock-cur .hd-row { display: flex; align-items: center; gap: 8px; margin-bottom: 12px; }
.mock-cur .hd-row b { font-size: 13px; }
.mock-cur .ai-badge { background: #f3e8ff; color: #7c3aed; border-radius: 999px;
  padding: 2px 10px; font-size: 9px; font-weight: 700; }
.mock-cur .grid { display: grid; grid-template-columns: 1fr 1fr; gap: 10px; }
.mock-cur .card { border: 1px solid var(--line); border-radius: 10px; padding: 12px; }
.mock-cur .card .ti { color: var(--blue); font-weight: 600; }
.mock-cur .card .au { color: #4a5565; margin-top: 2px; }
.mock-cur .card .jn { color: #9ca3af; font-size: 10px; }

/* STEP04: 마이서재 */
.mock-lib h4 { font-size: 15px; font-weight: 800; }
.mock-lib .sub { color: #6b7280; margin-bottom: 12px; }
.mock-lib .cards { display: grid; grid-template-columns: repeat(4,1fr); gap: 8px; margin-bottom: 14px; }
.mock-lib .scard { border-radius: 10px; padding: 10px 12px; }
.mock-lib .scard b { display: block; font-size: 14px; }
.mock-lib .scard small { color: #6b7280; font-size: 9px; }
.mock-lib .scard.c1 { background: #eff6ff; }
.mock-lib .scard.c2 { background: #ecfdf5; }
.mock-lib .scard.c3 { background: #f5f3ff; }
.mock-lib .scard.c4 { background: #fff7ed; }
.mock-lib .tabs { display: flex; gap: 4px; border-bottom: 1px solid var(--line); margin-bottom: 10px; }
.mock-lib .tabs span { padding: 6px 10px; color: #6b7280; font-size: 10px; }
.mock-lib .tabs span.on { color: var(--blue); font-weight: 700; border-bottom: 2px solid var(--blue); }
.mock-lib .sort { display: flex; gap: 8px; align-items: center; color: #6b7280; font-size: 10px; margin-bottom: 10px; }
.mock-lib .sort .on { background: var(--blue-weak); color: var(--blue); border-radius: 999px; padding: 2px 8px; font-weight: 600; }
.mock-lib .sort .total { margin-left: auto; }
.mock-lib .item { border-top: 1px solid var(--bg-2); padding: 9px 0; }
.mock-lib .item .ti { font-weight: 600; color: #161616; }
.mock-lib .item .au { color: #6b7280; font-size: 10px; }
.mock-lib .item .meta { display: flex; gap: 8px; align-items: center; margin-top: 3px; font-size: 9px; color: #9ca3af; }
.mock-lib .item .kci { background: #e7f6ec; color: #008236; border-radius: 4px; padding: 1px 6px; font-weight: 700; }

/* ---------- Contact (심플) ---------- */
.contact-sec { background: #fff; text-align: center; }
.contact-sec h2 { font-size: 28px; font-weight: 800; color: #2e3092; } /* KERD 로고 색상 */
.contact-sec p { color: var(--ink-2); margin-top: 10px; }
.contact-sec .cta { margin-top: 26px; display: flex; justify-content: center; }
.contact-sec .mail { margin-top: 18px; font-size: var(--fs-14); color: var(--gray); }
.contact-sec .mail a { color: var(--blue); font-weight: 600; }

/* =========================================================
   모바일 반응형 — 이 페이지(about)에만 적용
   (헤더/푸터 공통 컴포넌트는 common.css를 건드리지 않고
    about.css에서 페이지 한정 오버라이드)
   ========================================================= */
@media (max-width: 768px) {
  /* 헤더: 좁은 화면에서 GNB 메뉴 숨김, 로고+우측 액션만 유지 */
  .hd__in { height: 56px; gap: 16px; }
  .hd__nav { display: none; }
  .hd__logo img { height: 26px; }
  .hd__right { gap: 10px; }

  /* 공통 섹션 */
  .sec { padding: 56px 0; }
  .sec__title { font-size: 24px; }
  .sec__desc { font-size: var(--fs-14); }
  .sec__desc br { display: none; }

  /* Hero */
  .hero__sub { font-size: var(--fs-16); }
  .hero__stats { display: grid; grid-template-columns: repeat(2, auto); gap: 20px 48px;
    justify-content: center; }
  .hero__stats .stat b { font-size: 26px; }
  .hero__cta { flex-direction: column; align-items: stretch; max-width: 320px; margin-left: auto; margin-right: auto; }
  .btn--hero { text-align: center; }

  /* What is KERD */
  .books { padding: 24px 20px; }
  .books__track { --book-gap: 10px; animation-duration: 28s; }
  .books__track img { height: 132px; }

  /* STEP 스텝퍼: 2×2 유지, 설명(d) 숨김 */
  .step-tabs { margin-top: 32px; }
  .step-tab .d { display: none; }
  .step-tab .t { font-size: var(--fs-14); }

  /* STEP 행 */
  .step-row { gap: 28px; padding: 40px 0; }
  .step-info h3 { font-size: 24px; }
  .step-info > p { font-size: var(--fs-16); }

  /* 미니 목업 내부 */
  .mock__nav { gap: 12px; padding-left: 14px; padding-right: 14px; }
  .mock__nav .menu { overflow-x: auto; justify-content: flex-start; gap: 14px;
    white-space: nowrap; scrollbar-width: none; }
  .mock__nav .menu::-webkit-scrollbar { display: none; }
  .mock__search { flex-wrap: wrap; padding-left: 14px; padding-right: 14px; }
  .mock__search .q { flex: 1 1 100%; }
  .mock__body { padding: 14px; }
  .mock-cur .grid { grid-template-columns: 1fr; }

  /* ── STEP02 논문 상세: 실서비스 모바일 화면 구조에 맞춤 ──
     순서 = 제목 · 영문 · 저자 → 통계 → 메타 → 키워드/초록 → 다운로드 → 도구 */
  .mock-paper { display: grid; grid-template-columns: minmax(0, 1fr) auto;
    column-gap: 6px; row-gap: 0; }
  .mock-paper .main, .mock-paper .side { display: contents; }
  .mock-paper .main > *, .mock-paper .side > * { grid-column: 1 / -1; }
  .mock-paper .main > *:nth-child(-n+3) { order: 1; }   /* 제목·영문제목·저자 */
  .mock-paper .stats { order: 2; }
  .mock-paper .main > *:nth-child(n+4)  { order: 3; }   /* 메타 이후 전체 */
  /* 다운로드 + 아이콘 버튼을 한 줄에 배치 */
  .mock-paper .dl    { order: 4; grid-column: 1; margin-top: 14px; }
  .mock-paper .tools { order: 5; grid-column: 2; margin-top: 14px; }
  /* 통계: 4열 분할 박스 */
  .mock-paper .stats { flex-direction: row; margin-top: 14px; padding: 11px 0; gap: 0; }
  .mock-paper .stats .row { flex: 1; flex-direction: column; align-items: center; gap: 2px;
    border-right: 1px solid var(--line); }
  .mock-paper .stats .row:last-child { border-right: 0; }
  .mock-paper .stats .row.m-only { display: flex; }
  .mock-paper .stats i { display: none; }
  .mock-paper .stats b { font-size: 15px; text-align: center; }
  .mock-paper .stats small { display: block; text-align: center; }
  /* 도구: 아이콘 버튼 (다운로드 오른쪽) */
  .mock-paper .tools { border: 0; padding: 0; display: flex; gap: 6px; }
  .mock-paper .tools .cap, .mock-paper .tools .d-only { display: none; }
  .mock-paper .tools div { width: 38px; height: 100%; min-height: 30px; padding: 0; font-size: 0;
    border: 1px solid var(--line); border-radius: 10px; background: #fff;
    display: flex; align-items: center; justify-content: center; }
  .mock-paper .tools div span { display: none; }
  .mock-paper .tools .t-save::before { content: "🗂"; font-size: 13px; }
  .mock-paper .tools .t-link::before { content: "🔗"; font-size: 13px; }

  /* ── STEP04 마이서재: 실서비스 모바일 화면 구조에 맞춤 ── */
  .mock-lib .m-only { display: flex; }
  .mock-lib .tabs, .mock-lib .sort { display: none; }
  /* 요약 카드: 흰 배경 + 컬러 아이콘 칩 */
  .mock-lib .cards { grid-template-columns: repeat(2, 1fr); gap: 10px; }
  .mock-lib .cards .scard { background: #fff; border: 1px solid var(--line); padding: 10px 12px 11px; }
  .mock-lib .scard i { display: flex; width: 24px; height: 24px; border-radius: 7px;
    align-items: center; justify-content: center; font-size: 12px; margin-bottom: 8px; }
  .mock-lib .scard.c1 i { background: #dbeafe; }
  .mock-lib .scard.c2 i { background: #d1fae5; }
  .mock-lib .scard.c3 i { background: #ede9fe; }
  .mock-lib .scard.c4 i { background: #ffedd5; }
  .mock-lib .scard b { font-size: 16px; }
  /* 현재 목록 헤더 (탭 대체) */
  .mock-lib .lib-head { align-items: center; gap: 6px; padding: 9px 10px; margin-bottom: 10px;
    background: var(--bg-2); border-radius: 8px; font-size: 11px; color: #161616; }
  /* 전체 선택 + 정렬 드롭다운 */
  .mock-lib .lib-ctl { align-items: center; justify-content: space-between; margin-bottom: 8px; }
  .mock-lib .lib-ctl .chk { display: flex; align-items: center; gap: 6px; color: #6b7280; font-size: 10px; }
  .mock-lib .lib-ctl .chk::before { content: ""; width: 12px; height: 12px;
    border: 1px solid #cbd5e1; border-radius: 3px; }
  .mock-lib .lib-ctl .sel { border: 1px solid var(--line); border-radius: 6px;
    padding: 3px 8px; color: #4a5565; font-size: 10px; }
  /* 총 건수 + 삭제 */
  .mock-lib .lib-cnt { align-items: center; justify-content: space-between;
    margin-bottom: 2px; color: #6b7280; font-size: 10px; }
  .mock-lib .lib-cnt .del { color: #ef4444; }
  /* 목록: 체크박스 + 새 창 아이콘, 저자/학회지 2줄, 저장일 별도 줄 */
  .mock-lib .item { position: relative; padding: 10px 16px 10px 20px; }
  .mock-lib .item::before { content: ""; position: absolute; left: 0; top: 13px;
    width: 12px; height: 12px; border: 1px solid #cbd5e1; border-radius: 3px; }
  .mock-lib .item::after { content: "↗"; position: absolute; right: 0; top: 10px;
    color: #9ca3af; font-size: 10px; }
  .mock-lib .item .au .jn { display: block; }
  .mock-lib .item .meta { flex-wrap: wrap; }
  .mock-lib .item .meta .dt { flex-basis: 100%; margin-top: 2px; }

  /* Contact */
  .contact-sec h2 { font-size: 22px; }

  /* 푸터 */
  .ft__links { gap: 20px; flex-wrap: wrap; }
  .ft__grid { flex-direction: column; gap: 20px; }
  .ft__biz .gap { width: 10px; }
}

@media (max-width: 420px) {
  .hero__title { font-size: 28px; }
  .hero__stats { gap: 16px 32px; }
  .mock-lib .sort { flex-wrap: wrap; }
}