:root {
  --paper: #ffffff;
  --ink: #202020;
  --muted: rgba(32, 32, 32, 0.58);
  --line: rgba(32, 32, 32, 0.12);
  --shadow: 0 8px 16px rgba(16, 16, 16, 0.18);
  --shadow-active: 0 12px 22px rgba(16, 16, 16, 0.24);
  --card-width: min(46vw, 465px);
  --card-ratio: 1.55;
  --rail-width: 10.5rem;
}

* {
  box-sizing: border-box;
}

html,
body {
  margin: 0;
  min-height: 100%;
  width: 100%;
  overflow-x: hidden;
  background: var(--paper);
  color: var(--ink);
  overscroll-behavior: none;
}

body {
  font-family: Calibri, Candara, "Segoe UI", Optima, Arial, sans-serif;
}

html.is-low-memory .archive-rail-inner {
  background: rgba(255, 255, 255, 0.9);
  box-shadow: 0 8px 20px rgba(16, 16, 16, 0.07);
  backdrop-filter: blur(8px);
  -webkit-backdrop-filter: blur(8px);
}

html.is-low-memory .postcard,
html.is-low-memory .postcard-inner {
  transition-duration: 140ms;
}

html.is-low-memory .postcard:hover {
  filter: none;
}

html.is-low-memory .postcard-inner {
  box-shadow: 0 7px 18px rgba(16, 16, 16, 0.1);
}

button,
input,
textarea,
select {
  font: inherit;
}

img {
  display: block;
  max-width: 100%;
  user-select: none;
  -webkit-user-drag: none;
}

.page-shell {
  position: relative;
  min-height: 100vh;
  overflow: hidden;
}

.archive-rail {
  position: fixed;
  top: 0.9rem;
  left: 0.9rem;
  bottom: 0.9rem;
  z-index: 1200;
  width: var(--rail-width);
  display: flex;
  align-items: flex-start;
  justify-content: flex-start;
  pointer-events: none;
}

.archive-rail-inner {
  pointer-events: auto;
  display: flex;
  flex-direction: column;
  align-items: stretch;
  gap: 0.9rem;
  width: 100%;
  max-height: 100%;
  padding: 1rem 0.75rem;
  border: 1px solid rgba(32, 32, 32, 0.08);
  border-radius: 1rem;
  background: rgba(255, 255, 255, 0.84);
  box-shadow: 0 10px 28px rgba(16, 16, 16, 0.08);
  backdrop-filter: blur(14px);
  -webkit-backdrop-filter: blur(14px);
}

.archive-rail-label {
  display: inline-flex;
  align-items: center;
  gap: 0.45rem;
  margin: 0;
  font-size: 0.74rem;
  letter-spacing: 0.22em;
  text-transform: uppercase;
  color: var(--muted);
}

.archive-rail-logo {
  width: 1rem;
  height: 1rem;
  object-fit: contain;
  flex: 0 0 auto;
}

.archive-tree {
  display: flex;
  flex-direction: column;
  gap: 0.35rem;
  overflow-y: auto;
  overflow-x: hidden;
  min-height: 0;
  padding-right: 0.05rem;
  scrollbar-width: none;
}

.archive-tree::-webkit-scrollbar {
  width: 0;
  height: 0;
}

.archive-year,
.archive-month {
  display: flex;
  flex-direction: column;
  gap: 0.22rem;
}

.archive-toggle,
.archive-week {
  width: 93%;
  padding: 0.55rem 0.7rem;
  border: 1px solid rgba(32, 32, 32, 0.1);
  border-radius: 0.9rem;
  background: rgba(255, 255, 255, 0.78);
  color: rgba(32, 32, 32, 0.76);
  cursor: pointer;
  text-align: left;
  transition:
    border-color 160ms ease,
    background-color 160ms ease,
    color 160ms ease,
    transform 160ms ease;
}

.archive-toggle:hover,
.archive-week:hover {
  background: rgba(255, 255, 255, 0.96);
  transform: translateX(2px);
}

.archive-toggle.is-open,
.archive-week.is-active {
  border-color: rgba(32, 32, 32, 0.18);
  background: rgba(32, 32, 32, 0.92);
  color: #ffffff;
}

.archive-toggle {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 0.45rem;
}

.archive-toggle-depth-month {
  margin-left: 0.55rem;
  border-radius: 0.8rem;
}

.archive-toggle-label,
.archive-week-label,
.archive-week-count,
.archive-toggle-count {
  display: block;
}

.archive-toggle-label,
.archive-week-label {
  min-width: 0;
}

.archive-toggle-label,
.archive-week-label {
  font-size: 0.76rem;
  letter-spacing: 0.08em;
  text-transform: uppercase;
}

.archive-toggle-count,
.archive-week-count {
  flex-shrink: 0;
  min-width: 1.1rem;
  text-align: right;
  font-size: 0.78rem;
  opacity: 0.7;
}

.archive-months,
.archive-weeks {
  display: none;
  flex-direction: column;
  gap: 0.22rem;
}

.archive-year.is-open > .archive-months,
.archive-month.is-open > .archive-weeks {
  display: flex;
}

.archive-weeks {
  margin-left: 1.5rem;
}

.archive-week {
  padding: 0.48rem 0.7rem;
  border-radius: 0.78rem;
}

.pile-stage {
  position: relative;
  min-height: 100vh;
}

.pile {
  position: relative;
  width: 100vw;
  min-height: 100vh;
  isolation: isolate;
}

.postcard {
  position: absolute;
  top: 0;
  left: 0;
  width: var(--card-width);
  aspect-ratio: var(--card-ratio);
  padding: 0;
  border: 0;
  background: transparent;
  cursor: grab;
  touch-action: none;
  user-select: none;
  perspective: 1500px;
  transition: transform 320ms cubic-bezier(0.22, 1, 0.36, 1);
  contain: layout paint style;
}

.postcard:hover {
  filter: none;
}

.postcard:focus-visible {
  outline: none;
}

.postcard.is-dragging {
  cursor: grabbing;
  transition: none;
  z-index: 9999;
}

.postcard.is-dragging,
.postcard.is-open {
  will-change: transform;
}

.postcard.is-open {
  filter: none;
}

.postcard-inner {
  position: relative;
  width: 100%;
  height: 100%;
  border-radius: 0.42rem;
  transform-style: preserve-3d;
  transition: transform 520ms cubic-bezier(0.2, 0.7, 0.2, 1);
  box-shadow: var(--shadow);
}

.postcard:hover .postcard-inner,
.postcard:focus-visible .postcard-inner,
.postcard.is-open .postcard-inner,
.postcard.is-dragging .postcard-inner {
  box-shadow: var(--shadow-active);
}

.postcard.is-open .postcard-inner {
  transform: rotateY(180deg);
}

.postcard-face {
  position: absolute;
  inset: 0;
  overflow: hidden;
  border-radius: 0.42rem;
  backface-visibility: hidden;
  background: #faf9f6;
}

.postcard-front {
  display: grid;
  grid-template-rows: 1fr auto;
}

.postcard-image {
  width: 100%;
  height: 100%;
  object-fit: cover;
  background: #f2f2f2;
  pointer-events: none;
  user-select: none;
  -webkit-user-drag: none;
  transform: translateZ(0);
}

.front-caption {
  display: flex;
  justify-content: flex-end;
  align-items: center;
  min-height: 2.7rem;
  padding: 0.55rem 0.8rem 0.65rem;
  border-top: 1px solid rgba(255, 255, 255, 0.7);
  background: linear-gradient(to top, rgba(11, 11, 11, 0.52), rgba(11, 11, 11, 0));
  color: rgba(255, 255, 255, 0.86);
  font-family: "SFMono-Regular", Consolas, "Liberation Mono", monospace;
  font-size: 0.7rem;
  letter-spacing: 0.08em;
  text-transform: uppercase;
}

.postcard-back {
  display: flex;
  flex-direction: column;
  gap: 1rem;
  padding: 1.25rem;
  background: #fcfbf7;
  transform: rotateY(180deg);
  overflow: hidden;
}

.back-title {
  margin: 0;
  font-family: Calibri, Candara, "Segoe UI", Optima, Arial, sans-serif;
  font-weight: 700;
  font-size: 1.72rem;
  line-height: 1.02;
  flex: 0 0 auto;
}

.back-message {
  flex: 1 1 auto;
  min-height: 0;
  overflow-y: auto;
  padding-right: 0.45rem;
  font-size: 1.06rem;
  line-height: 1.68;
  color: rgba(32, 32, 32, 0.88);
  scrollbar-width: thin;
  scrollbar-color: rgba(32, 32, 32, 0.24) transparent;
  overscroll-behavior: contain;
  touch-action: pan-y;
  -webkit-overflow-scrolling: touch;
}

.back-message p,
.back-message ul,
.back-message ol {
  margin: 0 0 0.95rem;
}

.back-message p:last-child,
.back-message ul:last-child,
.back-message ol:last-child {
  margin-bottom: 0;
}

.back-message a {
  color: inherit;
  text-decoration-thickness: 1px;
  text-underline-offset: 0.12em;
}

.back-message strong,
.back-message b {
  font-weight: 700;
}

.back-message em,
.back-message i {
  font-style: italic;
}

.back-message::-webkit-scrollbar {
  width: 0.52rem;
}

.back-message::-webkit-scrollbar-thumb {
  background: rgba(32, 32, 32, 0.22);
  border-radius: 999px;
}

.back-message::-webkit-scrollbar-track {
  background: transparent;
}

@media (max-width: 900px) {
  :root {
    --card-width: min(68vw, 400px);
    --rail-width: 8.6rem;
  }
}

@media (max-width: 640px) {
  :root {
    --card-width: min(84vw, 360px);
    --rail-width: 7.9rem;
  }

  .archive-rail-inner {
    gap: 0.7rem;
    padding: 0.75rem 0.4rem;
  }

  .archive-toggle,
  .archive-week {
    padding: 0.42rem 0.38rem;
    border-radius: 0.72rem;
  }

  .archive-toggle-depth-month {
    margin-left: 0.18rem;
  }

  .archive-weeks {
    margin-left: 0.56rem;
  }

  .archive-toggle-label,
  .archive-week-label {
    font-size: 0.66rem;
  }

  .archive-toggle-count,
  .archive-week-count {
    min-width: 0.95rem;
    font-size: 0.68rem;
  }

  .postcard-back {
    gap: 0.8rem;
    padding: 1rem;
  }

  .back-title {
    font-size: 1.36rem;
  }

  .back-message {
    font-size: 0.95rem;
    line-height: 1.58;
  }
}

@media (prefers-reduced-motion: reduce) {
  .postcard,
  .postcard-inner {
    transition-duration: 0ms;
  }
}