/* ==========================================================
   header.css - 상단 헤더 / GNB / 모바일 메뉴
   ========================================================== */
.header {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  z-index: 100;
  height: var(--header-height);
  background: rgba(255, 255, 255, 0.95);
  border-bottom: 1px solid transparent;
  transition: border-color var(--transition), box-shadow var(--transition);
}
.header.is-scrolled {
  border-color: var(--color-border);
  box-shadow: 0 2px 12px rgba(0, 0, 0, 0.05);
}

.header__inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 100%;
}

.header__logo img { height: 48px; width: auto; }

.gnb { display: flex; gap: 40px; }
.gnb__link { position: relative; font-weight: 500; transition: color var(--transition); }
.gnb__link:hover,
.gnb__link.is-active { color: var(--color-primary); }

/* 데스크톱 GNB 밑줄 표시 */
.gnb__link::after {
  content: '';
  position: absolute;
  left: 0;
  right: 0;
  bottom: -6px;
  height: 2px;
  background: var(--color-primary);
  transform: scaleX(0);
  transition: transform var(--transition);
}
.gnb__link:hover::after,
.gnb__link.is-active::after { transform: scaleX(1); }

/* 햄버거 버튼 */
.header__toggle { display: none; width: 28px; height: 20px; position: relative; }
.header__toggle span {
  position: absolute;
  left: 0;
  width: 100%;
  height: 2px;
  background: var(--color-text);
  transition: var(--transition);
}
.header__toggle span:nth-child(1) { top: 0; }
.header__toggle span:nth-child(2) { top: 9px; }
.header__toggle span:nth-child(3) { top: 18px; }

@media (max-width: 768px) {
  .header__toggle { display: block; }

  .gnb {
    position: fixed;
    top: var(--header-height);
    left: 0;
    right: 0;
    flex-direction: column;
    gap: 0;
    background: #fff;
    border-bottom: 1px solid var(--color-border);
    display: none;
  }
  .gnb.is-open { display: flex; }
  .gnb__link { padding: 16px 20px; border-top: 1px solid var(--color-border); }
  .gnb__link::after { display: none; }

  .header__toggle.is-open span:nth-child(1) { top: 9px; transform: rotate(45deg); }
  .header__toggle.is-open span:nth-child(2) { opacity: 0; }
  .header__toggle.is-open span:nth-child(3) { top: 9px; transform: rotate(-45deg); }
}