body {
  max-width: 480px;
  margin: 0 auto;
  padding: var(--page-padding);
  padding-bottom: calc(var(--nav-height) + 16px + env(safe-area-inset-bottom, 0px));
}
body.pc-mode {
  max-width: none;
  padding: var(--section-gap);
  padding-bottom: var(--section-gap);
}

#auth-screen {
  max-width: 480px;
  margin: 0 auto;
  min-height: 100vh;
  display: flex;
  flex-direction: column;
  justify-content: center;
}

.top-bar {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 8px;
  margin-bottom: var(--card-gap);
}
.top-bar .app-title { font-size: 18px; font-weight: 800; color: var(--navy); }
.top-bar .top-actions { display: flex; gap: 8px; }
body.pc-mode .top-bar { max-width: 1200px; margin: 0 auto var(--card-gap); }

.icon-btn {
  width: 44px; height: 44px; border-radius: 50%;
  border: 1px solid var(--gray-300); background: var(--card);
  display: flex; align-items: center; justify-content: center;
  font-size: 18px; transition: var(--transition); flex-shrink: 0;
}
.icon-btn:hover { background: var(--gray-100); }

#pc-layout { display: block; }

/* 하단 고정 탭바 (모바일 기본) */
.nav-tabs {
  display: flex; gap: 4px;
  position: fixed; left: 0; right: 0; bottom: 0; z-index: 100;
  max-width: 480px; margin: 0 auto;
  background: var(--card); border-top: 1px solid var(--gray-100);
  border-radius: var(--radius-bottom-nav) var(--radius-bottom-nav) 0 0;
  padding: 10px 8px calc(10px + env(safe-area-inset-bottom, 0px));
  box-shadow: var(--shadow-card);
  /* 안드로이드 Chrome 계열에서 스크롤 중 fixed 요소가 사라지는 리페인트 지연 버그 방지 */
  transform: translateZ(0);
  -webkit-transform: translateZ(0);
  will-change: transform;
}
.nav-tabs button {
  flex: 1; display: flex; flex-direction: column; align-items: center; gap: 4px;
  padding: 8px 4px; background: transparent; border: none; border-radius: 16px;
  font-weight: 600; font-size: 11px; color: var(--gray-500); position: relative;
  min-height: 48px; transition: var(--transition);
}
.nav-tabs .nav-icon { font-size: 22px; line-height: 1; }
.nav-tabs button.active { color: var(--primary); }
.nav-tabs button.active::before {
  content: ''; position: absolute; top: 0; left: 50%; transform: translateX(-50%);
  width: 20px; height: 3px; border-radius: 0 0 3px 3px; background: var(--primary);
}

[id^="section-"] { display: none; }
[id^="section-"].active-section { display: block; }

#pc-widget-rail { display: none; }

/* PC 모드: 좌측 사이드바 + 메인 + 우측 위젯 레일 */
body.pc-mode #pc-layout {
  display: flex; align-items: flex-start; gap: var(--section-gap);
  max-width: 1200px; margin: 0 auto;
}
body.pc-mode .pc-sidebar-col {
  display: flex; flex-direction: column; flex-shrink: 0; width: 220px;
  position: sticky; top: 16px;
}
body.pc-mode .nav-tabs {
  position: static; left: auto; right: auto; bottom: auto; max-width: none; margin: 0;
  flex-direction: column; border-radius: var(--radius-card); border: 1px solid var(--gray-100);
  padding: 12px;
}
body.pc-mode .nav-tabs button {
  flex-direction: row; justify-content: flex-start; gap: 12px;
  padding: 14px 16px; font-size: 15px; border-radius: 14px; min-height: 0;
}
body.pc-mode .nav-tabs .nav-icon { font-size: 20px; }
body.pc-mode .nav-tabs button.active { background: var(--primary-light); }
body.pc-mode .nav-tabs button.active::before { display: none; }
body.pc-mode [id^="section-"] { flex: 1; min-width: 0; }
body.pc-mode #pc-widget-rail { display: block; width: 300px; flex-shrink: 0; }

.fab {
  position: fixed; right: 20px;
  bottom: calc(var(--nav-height) + 20px + env(safe-area-inset-bottom, 0px));
  width: 56px; height: 56px; border-radius: 50%;
  background: var(--primary); color: #fff; font-size: 28px; border: none;
  box-shadow: var(--shadow-fab); z-index: 90;
  display: flex; align-items: center; justify-content: center; transition: var(--transition);
}
.fab:active { transform: scale(0.95); }
body.pc-mode .fab { display: none; }

@media (max-width: 380px) {
  .nav-tabs .nav-label { font-size: 10px; }
}