/* ==========================================================
   butterfog 스타일
   색과 크기는 :root 변수에서 한 번에 바꿀 수 있어요.
   ========================================================== */

:root {
  /* 기본 배경 (네이비) */
  --navy-900: #0b1530;
  --navy-800: #16264d;
  --navy-700: #22355f;

  /* 글자 */
  --text: #dfe7f5;
  --text-muted: #9fb0cf;

  /* 창(유리 느낌) */
  --glass: rgba(20, 34, 68, 0.55);
  --glass-light: rgba(255, 255, 255, 0.04);
  --line: rgba(200, 215, 245, 0.18);
  --shadow: rgba(0, 0, 0, 0.45);

  /* 창 왼쪽 위 점 */
  --dot-close: #ff6058;
  --dot-minimize: #ffbd2e;
  --dot-zoom: #28c93f;

  /* 폴더 */
  --folder-back: #7fa3e0;
  --folder-front: #a9c4f0;
  --folder-size: 64px;

  /* 안개 */
  --fog-1: rgba(200, 215, 245, 0.22);
  --fog-2: rgba(170, 190, 230, 0.20);
  --fog-3: rgba(220, 230, 250, 0.25);

  /* 산과 호수 (SVG) */
  --mountain-far: #5a74ab;
  --mountain-near: #2c4274;
  --mountain-near-mid: #34497c;
  --mountain-near-end: #4a6399;
  --shore: #2a3f70;
  --water-light: #8aa3d4;
  --water-mid: #3a5086;
  --mist: #d3dffa;
  --streak: #cfdcf8;

  /* 글 화면 */
  --post-bg: rgba(11, 21, 48, 0.82);
  --post-bar-bg: rgba(11, 21, 48, 0.7);
  --card-bg: rgba(255, 255, 255, 0.05);
  --thumb-from: #3a4f82;
  --thumb-to: #1b2a52;

  /* 글꼴 */
  --font-serif: "Noto Serif KR", "Nanum Myeongjo", serif;
  --font-sans: system-ui, sans-serif;

  /* 휴대폰 상단·하단 안전 영역 */
  box-sizing: border-box;
  padding-top: env(safe-area-inset-top, 0px);
  padding-bottom: env(safe-area-inset-bottom, 0px);
}

*,
*::before,
*::after {
  box-sizing: border-box;
}

html {
  scroll-padding-top: env(safe-area-inset-top, 0px);
}

html,
body {
  height: 100%;
  margin: 0;
}

body {
  background: var(--navy-900);
  color: var(--text);
  font-family: var(--font-serif);
  overflow: hidden;
}


/* ==========================================================
   배경
   ========================================================== */

.scene {
  position: fixed;
  inset: 0;
  background: linear-gradient(180deg, var(--navy-900) 0%, var(--navy-800) 55%, var(--navy-700) 100%);
}

.fog {
  position: absolute;
  inset: -20%;
  background:
    radial-gradient(40% 30% at 20% 70%, var(--fog-1), transparent 70%),
    radial-gradient(45% 30% at 75% 60%, var(--fog-2), transparent 70%),
    radial-gradient(60% 25% at 50% 90%, var(--fog-3), transparent 70%);
  filter: blur(30px);
  animation: drift 40s ease-in-out infinite alternate;
}

.fog-slow {
  animation-duration: 60s;
  animation-direction: alternate-reverse;
  opacity: 0.7;
}

@keyframes drift {
  from { transform: translateX(-4%); }
  to   { transform: translateX(4%); }
}

.landscape {
  position: absolute;
  inset: 0;
  width: 100%;
  height: 100%;
}

/* SVG 그라데이션 색 (투명도는 index.html에 있어요) */
#grad-far stop {
  stop-color: var(--mountain-far);
}

#grad-near stop:nth-child(1) { stop-color: var(--mountain-near); }
#grad-near stop:nth-child(2) { stop-color: var(--mountain-near-mid); }
#grad-near stop:nth-child(3) { stop-color: var(--mountain-near-end); }

#grad-water stop:nth-child(1) { stop-color: var(--water-light); }
#grad-water stop:nth-child(2) { stop-color: var(--water-mid); }
#grad-water stop:nth-child(3) { stop-color: var(--navy-900); }

#grad-mist stop {
  stop-color: var(--mist);
}

.mountain-far  { fill: url(#grad-far); }
.mountain-near { fill: url(#grad-near); }

.shore {
  fill: var(--shore);
  opacity: 0.7;
}

.water { fill: url(#grad-water); }
.mist  { fill: url(#grad-mist); }

.streaks {
  fill: var(--streak);
}


/* ==========================================================
   창
   ========================================================== */

.window {
  position: relative;
  display: flex;
  flex-direction: column;
  width: min(1000px, calc(100% - 24px));
  height: calc(100% - max(24px, 6vh));
  margin: max(12px, 3vh) auto;
  overflow: hidden;
  background: var(--glass);
  -webkit-backdrop-filter: blur(14px);
  backdrop-filter: blur(14px);
  border: 1px solid var(--line);
  border-radius: 14px;
  box-shadow: 0 30px 80px var(--shadow);
}

.titlebar {
  display: flex;
  flex: none;
  align-items: center;
  height: 44px;
  padding: 0 16px;
  background: var(--glass-light);
  border-bottom: 1px solid var(--line);
}

.window-buttons {
  display: flex;
  gap: 8px;
}

.dot {
  display: block;
  width: 12px;
  height: 12px;
  border-radius: 50%;
}

.dot-close    { background: var(--dot-close); }
.dot-minimize { background: var(--dot-minimize); }
.dot-zoom     { background: var(--dot-zoom); }

.titlebar-text {
  flex: 1;
  margin: 0 52px 0 0;
  overflow: hidden;
  font-size: 13px;
  font-weight: 400;
  color: var(--text-muted);
  text-align: center;
  text-overflow: ellipsis;
  white-space: nowrap;
}


/* ==========================================================
   탭 (책 / Book)
   ========================================================== */

.tabs {
  display: flex;
  flex: none;
  justify-content: center;
  gap: 6px;
  padding-top: 14px;
}

.tab {
  padding: 6px 18px;
  font: inherit;
  font-size: 14px;
  color: var(--text-muted);
  cursor: pointer;
  background: none;
  border: 1px solid transparent;
  border-radius: 20px;
}

.tab.is-active {
  color: var(--text);
  background: rgba(255, 255, 255, 0.07);
  border-color: var(--line);
}


/* ==========================================================
   폴더
   ========================================================== */

.content {
  position: relative;
  flex: 1;
  overflow: auto;
}

.folder-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(104px, 1fr));
  gap: 24px 8px;
  max-width: 820px;
  margin: 0 auto;
  padding: 40px 36px;
}

.folder {
  padding: 6px;
  font: inherit;
  color: var(--text);
  text-align: center;
  cursor: pointer;
  background: none;
  border: 0;
}

.folder-icon {
  display: block;
  width: var(--folder-size);
  height: auto;
  margin: 0 auto 8px;
  filter: drop-shadow(0 6px 10px var(--shadow));
  transition: transform 0.2s;
}

.folder:hover .folder-icon,
.folder:focus-visible .folder-icon {
  transform: translateY(-4px);
}

.folder-back  { fill: var(--folder-back); }
.folder-front { fill: var(--folder-front); }

.folder-name {
  display: block;
  font-size: 13px;
  line-height: 1.4;
  word-break: keep-all;
}

.empty-message {
  padding: 60px 0;
  font-size: 14px;
  color: var(--text-muted);
  text-align: center;
}


/* ==========================================================
   글 화면
   ========================================================== */

.post-view {
  position: absolute;
  inset: 0;
  overflow: auto;
  background: var(--post-bg);
  -webkit-backdrop-filter: blur(10px);
  backdrop-filter: blur(10px);
}

.back-button {
  position: sticky;
  top: 0;
  z-index: 2;
  width: 100%;
  padding: 12px 20px;
  font: inherit;
  font-size: 13px;
  color: var(--text-muted);
  text-align: left;
  cursor: pointer;
  background: var(--post-bar-bg);
  border: 0;
  border-bottom: 1px solid var(--line);
}

.post-article {
  max-width: 720px;
  margin: 0 auto;
  padding: 28px 24px 60px;
  font-size: 15px;
  line-height: 1.9;
}

.post-title {
  margin: 0 0 6px;
  font-size: 22px;
  font-weight: 600;
  text-align: center;
}

.post-meta {
  margin-bottom: 26px;
  font-size: 13px;
  color: var(--text-muted);
  text-align: center;
}

.post-article p {
  margin: 0 0 1.1em;
}

/* 책 사이트 링크 카드 */
.link-card {
  display: flex;
  align-items: center;
  gap: 18px;
  margin: 22px 0;
  padding: 18px 22px;
  color: var(--text);
  text-decoration: none;
  background: var(--card-bg);
  border: 1px solid var(--line);
  border-radius: 10px;
}

.link-thumb {
  flex: none;
  width: 64px;
  height: 84px;
  background: linear-gradient(160deg, var(--thumb-from), var(--thumb-to));
  border-radius: 4px;
}

.link-thumb-default {
  width: 88px;
  height: 88px;
  object-fit: contain;
  background: none;
  border-radius: 0;
}

img.link-thumb:not(.link-thumb-default) {
  object-fit: cover;
}

.link-title {
  display: block;
  font-size: 14px;
  font-weight: 600;
}

.link-label {
  display: block;
  margin-top: 6px;
  font-size: 12px;
  line-height: 1.7;
  color: var(--text-muted);
}


/* ==========================================================
   푸터
   ========================================================== */

.footer {
  flex: none;
  padding: 8px 18px 12px;
  font-family: var(--font-sans);
  font-size: 11px;
  color: var(--text-muted);
  text-align: right;
}

.footer a {
  color: inherit;
  text-decoration: none;
}

.footer a:focus-visible {
  text-decoration: underline;
  text-underline-offset: 2px;
}


/* 움직임을 줄이고 싶은 사용자 설정 */
@media (prefers-reduced-motion: reduce) {
  .fog {
    animation: none;
  }
}