/* ==============================================
   Between Us
   ============================================== */

:root {
  /* Writing desk palette */
  --desk:       #D8C8AC;   /* page background — wooden desk surface */
  --user-paper: #F7F1E1;   /* user's letter — fresh stationery */
  --reply-tone: #EEDFC3;   /* reply letter — returned correspondence */
  --ink:        #442D1C;   /* primary text */
  --ink-warm:   #66371B;   /* secondary text, headings, signatures */
  --ink-meta:   #81754B;   /* metadata, dates, labels */
  --olive:      #3F3F2C;   /* primary accent — send button, active */
  --amber:      #84592B;   /* secondary accent — hover, decorative */

  /* Semantic tokens */
  --page:        var(--desk);
  --paper:       var(--user-paper);
  --paper-fold:  #DCCFA8;
  --paper-muted: rgba(247, 241, 225, 0.70);
  --paper-ink:   var(--user-paper);

  --heading:         var(--ink-warm);
  --muted:           var(--ink-meta);
  --accent:          var(--olive);
  --accent-readable: var(--amber);
  --secondary:       var(--ink-meta);
  --archive:         #7A6649;

  --border:       rgba(132, 89, 43, 0.20);
  --rule:         rgba(129, 117, 75, 0.16);
  --placeholder:  rgba(129, 117, 75, 0.52);
  --accent-faint: rgba(238, 223, 195, 0.30);
  --accent-line:  rgba(63, 63, 44, 0.28);
  --shadow-soft:  rgba(68, 45, 28, 0.12);
  --shadow-deep:  rgba(68, 45, 28, 0.20);

  /* Typography */
  --font-ui:          'Lato', 'Source Han Serif SC', 'Noto Serif SC', serif;
  --font-literary-ui: 'EB Garamond', 'Source Han Serif SC', 'Noto Serif SC', serif;
  --font-letter:      'EB Garamond', 'LXGW WenKai', '霞鶩文楷', serif;

  /* Legacy aliases — old variable names resolve to new values */
  --linen:      var(--user-paper);
  --latte:      var(--reply-tone);
  --clockwork:  var(--ink-warm);
  --cedar:      var(--ink-meta);
  --deep-olive: var(--olive);
  --cafe-noir:  var(--ink);
  --mauve:      var(--amber);
  --weathered:  var(--ink-meta);
  --espresso:   var(--ink);
  --caramel:    var(--ink-warm);
  --leafy:      var(--ink-meta);
  --sand:       var(--page);
  --cinnamon:   var(--amber);
  --cream:      var(--paper);
}

*, *::before, *::after {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

body {
  background: var(--page);
  color: var(--ink);
  font-family: var(--font-ui);
  font-weight: 300;
  min-height: 100vh;
}

#app {
  max-width: 660px;
  margin: 0 auto;
  padding: 2.5rem 1.5rem 5rem;
}

section { display: block; }
section.hidden { display: none !important; }
.hidden { display: none !important; }

::selection {
  background: rgba(132, 89, 43, 0.24);
  color: var(--ink);
}

button:focus-visible,
input:focus-visible,
textarea:focus-visible,
select:focus-visible {
  outline: 1px solid var(--amber);
  outline-offset: 3px;
}

/* --- Header ------------------------------------------ */

.header-right {
  display: flex;
  align-items: baseline;
  gap: 1.6rem;
}

.site-header {
  display: flex;
  align-items: baseline;
  justify-content: space-between;
  margin-bottom: 3rem;
  padding-bottom: 1rem;
  border-bottom: 1px solid var(--border);
}

.site-title {
  font-family: var(--font-literary-ui);
  font-size: 2.2rem;
  font-weight: 400;
  color: var(--ink);
  letter-spacing: 0.01em;
}

.home-btn {
  padding: 0;
  border: 0;
  border-bottom: 1px solid transparent;
  background: transparent;
  color: inherit;
  font: inherit;
  letter-spacing: inherit;
  cursor: pointer;
  transition: color 0.2s ease, border-color 0.2s ease;
}

.home-btn:hover,
.home-btn:focus-visible {
  color: var(--amber);
  border-bottom-color: rgba(132, 89, 43, 0.38);
}

.nav-btn {
  background: none;
  border: none;
  color: var(--ink-warm);
  font-family: var(--font-ui);
  font-size: 0.75rem;
  font-weight: 400;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  cursor: pointer;
  padding: 0;
  transition: color 0.2s;
}
.nav-btn:hover { color: var(--amber); }

/* --- Auth section ------------------------------------ */

.auth-stationery {
  max-width: 420px;
  margin: 2rem auto;
}

.auth-intro {
  font-family: var(--font-literary-ui);
  font-style: italic;
  color: var(--ink-warm);
  font-size: 1.05rem;
  margin-bottom: 2rem;
}

.auth-row {
  display: flex;
  align-items: baseline;
  gap: 1.5rem;
  border-bottom: 1px solid var(--rule);
  padding-bottom: 0.7rem;
  margin-bottom: 1.2rem;
}

.auth-error {
  font-family: var(--font-ui);
  font-size: 0.72rem;
  letter-spacing: 0.03em;
  color: #8a2f18;
  margin-bottom: 0.8rem;
}

.auth-error.is-notice {
  color: var(--ink-meta);
}

.auth-toggle-row {
  text-align: center;
  font-family: var(--font-ui);
  font-size: 0.72rem;
  letter-spacing: 0.05em;
  color: var(--ink-meta);
  margin-top: 1.4rem;
}

.auth-switch-btn {
  background: none;
  border: none;
  color: var(--amber);
  font-family: var(--font-ui);
  font-size: 0.72rem;
  letter-spacing: 0.05em;
  text-decoration: underline;
  text-underline-offset: 2px;
  cursor: pointer;
  padding: 0;
}

.auth-back-row {
  text-align: center;
  margin-top: 2rem;
  padding-top: 1.2rem;
  border-top: 1px solid var(--rule);
}

.auth-back-btn {
  background: none;
  border: none;
  font-family: var(--font-ui);
  font-size: 0.72rem;
  letter-spacing: 0.05em;
  color: var(--ink-meta);
  cursor: pointer;
  padding: 0;
}

.auth-back-btn:hover { color: var(--ink-warm); }

/* --- Name prompt ------------------------------------- */

.name-prompt {
  display: flex;
  flex-direction: column;
  align-items: center;
  text-align: center;
  min-height: 58vh;
  justify-content: center;
  gap: 1.6rem;
}

.name-intro {
  font-family: var(--font-literary-ui);
  font-style: italic;
  font-size: 1rem;
  color: var(--ink-meta);
}

.name-question {
  font-family: var(--font-literary-ui);
  font-size: 1.55rem;
  font-weight: 400;
  color: var(--ink-warm);
  display: block;
}

.name-input {
  background: none;
  border: none;
  border-bottom: 1px solid var(--accent-line);
  outline: none;
  font-family: var(--font-literary-ui);
  font-size: 1.4rem;
  color: var(--ink);
  text-align: center;
  width: 260px;
  padding-bottom: 0.3rem;
  transition: border-color 0.2s;
}
.name-input:focus { border-bottom-color: var(--amber); }
.name-input::placeholder { color: var(--placeholder); }

/* --- Stationery -------------------------------------- */

.stationery {
  background: var(--paper);
  border: 1px solid var(--border);
  box-shadow:
    0 1px 3px rgba(68, 45, 28, 0.10),
    0 4px 16px rgba(68, 45, 28, 0.14),
    0 14px 40px rgba(68, 45, 28, 0.16),
    inset 0 1px 0 rgba(255, 255, 255, 0.50);
  padding: 2.5rem 3rem;
  display: flex;
  flex-direction: column;
}

.stationery-to-row {
  display: flex;
  align-items: baseline;
  gap: 1rem;
  padding-bottom: 0.9rem;
  border-bottom: 1px solid var(--border);
  margin-bottom: 1.5rem;
}

.stationery-to-row:focus-within {
  border-bottom-color: var(--amber);
}

.field-label {
  font-family: var(--font-literary-ui);
  font-size: 1rem;
  color: var(--ink-meta);
  white-space: nowrap;
  flex-shrink: 0;
}

.field-input {
  background: none;
  border: none;
  outline: none;
  font-family: var(--font-literary-ui);
  font-size: 1.1rem;
  color: var(--ink);
  width: 100%;
}
.field-input:focus,
.field-input:focus-visible {
  outline: none;
  box-shadow: 0 2px 0 -1px rgba(132, 89, 43, 0.45);
}
.field-input::placeholder { color: var(--placeholder); }

.letter-textarea {
  width: 100%;
  min-height: 260px;
  background-image: repeating-linear-gradient(
    to bottom,
    transparent 0,
    transparent calc(1.75rem - 1px),
    var(--rule) calc(1.75rem - 1px),
    var(--rule) 1.75rem
  );
  background-attachment: local;
  background-color: transparent;
  border: none;
  outline: none;
  resize: none;
  font-family: var(--font-letter);
  font-size: 1.1rem;
  line-height: 1.75rem;
  color: var(--ink);
  padding: 0;
  transition: box-shadow 0.22s ease, background-color 0.22s ease;
  line-break: auto;
  overflow-wrap: break-word;
}

.letter-textarea:focus,
.letter-textarea:focus-visible {
  outline: none;
  background-color: rgba(132, 89, 43, 0.025);
  box-shadow:
    inset 2px 0 0 rgba(132, 89, 43, 0.28),
    0 8px 18px -18px rgba(68, 45, 28, 0.40);
}
.letter-textarea::placeholder { color: var(--placeholder); }
.letter-textarea::placeholder { font-family: var(--font-literary-ui); }

/* --- Voice reference --------------------------------- */

.voice-ref {
  margin-top: 1.4rem;
  border-top: 1px solid var(--border);
  padding-top: 0.85rem;
}

.voice-ref-toggle {
  font-family: var(--font-ui);
  font-size: 0.7rem;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--ink-meta);
  cursor: pointer;
  list-style: none;
  display: flex;
  align-items: center;
  gap: 0.5rem;
  user-select: none;
}
.voice-ref-toggle::-webkit-details-marker { display: none; }
.voice-ref-toggle::before {
  content: '▸';
  font-size: 0.55rem;
  display: inline-block;
  transition: transform 0.2s;
}
details[open] .voice-ref-toggle::before { transform: rotate(90deg); }

.optional-tag {
  font-style: normal;
  color: var(--ink-meta);
  font-size: 0.65rem;
  letter-spacing: 0.05em;
}

.voice-ref-body {
  padding: 0.85rem 0 0.2rem;
}

.voice-ref-desc {
  font-family: var(--font-literary-ui);
  font-style: italic;
  font-size: 0.88rem;
  color: var(--ink-meta);
  margin-bottom: 0.65rem;
  line-height: 1.5;
}

.voice-textarea {
  width: 100%;
  min-height: 80px;
  background: var(--accent-faint);
  border: 1px solid var(--border);
  outline: none;
  resize: vertical;
  font-family: var(--font-literary-ui);
  font-size: 0.95rem;
  line-height: 1.6;
  color: var(--ink);
  padding: 0.6rem 0.8rem;
}
.voice-textarea:focus,
.voice-textarea:focus-visible {
  outline: none;
  border-color: rgba(132, 89, 43, 0.52);
  box-shadow: 0 0 0 3px rgba(132, 89, 43, 0.08);
}
.voice-textarea::placeholder { color: var(--placeholder); }

.reply-language {
  display: flex;
  align-items: center;
  justify-content: flex-end;
  gap: 0.55rem;
  margin-top: 0.85rem;
  color: var(--ink-meta);
  font-family: var(--font-ui);
  font-size: 0.68rem;
  letter-spacing: 0.05em;
}

.reply-language select {
  padding: 0.28rem 1.5rem 0.28rem 0.38rem;
  border: 0;
  border-bottom: 1px solid var(--accent-line);
  border-radius: 0;
  background: transparent;
  color: var(--ink);
  font-family: var(--font-literary-ui);
  font-size: 0.9rem;
  cursor: pointer;
}

.reply-language select:focus,
.reply-language select:focus-visible {
  outline: none;
  border-bottom-color: var(--amber);
  box-shadow: 0 2px 0 -1px rgba(132, 89, 43, 0.30);
}

/* --- Send button ------------------------------------- */

.send-btn {
  display: block;
  margin: 2rem auto 0;
  padding: 0.72rem 2.6rem;
  background: var(--olive);
  color: var(--user-paper);
  border: none;
  font-family: var(--font-ui);
  font-size: 0.72rem;
  font-weight: 400;
  letter-spacing: 0.15em;
  text-transform: uppercase;
  cursor: pointer;
  transition: background 0.22s, transform 0.1s;
}
.send-btn:hover  { background: var(--amber); }
.send-btn:active { transform: translateY(1px); }

.send-btn.secondary {
  background: var(--ink-warm);
  color: var(--user-paper);
  border: none;
}
.send-btn.secondary:hover { background: var(--amber); }

/* --- Sending animation ------------------------------- */

.sending-stage {
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  min-height: 62vh;
  gap: 2.5rem;
}

.anim-letter {
  width: 110px;
  height: 148px;
  background: var(--paper);
  border: 1px solid var(--border);
  box-shadow: 0 2px 16px var(--shadow-soft);
  display: flex;
  flex-direction: column;
  justify-content: center;
  padding: 22px 16px;
  gap: 9px;
}

.letter-line {
  height: 1.5px;
  background: var(--rule);
  border-radius: 1px;
}
.letter-line.short { width: 58%; }

@keyframes letterFold {
  0%   { opacity: 1; transform: scale(1)    translateY(0); }
  30%  { opacity: 1; transform: scaleY(0.55) scaleX(0.9) translateY(5px); }
  60%  { opacity: 0.7; transform: scale(0.6) translateY(12px); }
  100% { opacity: 0; transform: scale(0.25) translateY(22px); }
}
.anim-letter.folding {
  animation: letterFold 0.75s ease-in forwards;
}

.anim-envelope {
  width: 196px;
  min-height: 142px;
  position: relative;
}

@keyframes envelopeTravel {
  0%, 100% { transform: translateY(0); }
  50%      { transform: translateY(-4px); }
}

@keyframes envAppear {
  0%   { opacity: 0; transform: scale(0.8) translateY(8px); }
  100% { opacity: 1; transform: scale(1) translateY(0); }
}
@keyframes envDepart {
  0%   { opacity: 1; transform: translateY(0) scale(1); }
  100% { opacity: 0; transform: translateY(-72px) scale(0.78); }
}

.anim-envelope.appearing { animation: envAppear 0.45s ease-out forwards; }
.anim-envelope.departing { animation: envDepart 1.1s ease-in forwards; }

.sending-caption {
  font-family: var(--font-literary-ui);
  font-style: italic;
  font-size: 1.4rem;
  color: var(--ink-meta);
  text-align: center;
  opacity: 0;
  transition: opacity 0.55s ease;
}

/* --- Reply ------------------------------------------- */

@keyframes replyAppear {
  from { opacity: 0; transform: translateY(14px); }
  to   { opacity: 1; transform: translateY(0); }
}

#replySection { animation: replyAppear 1.4s cubic-bezier(0.16, 1, 0.3, 1) both; }
#replySection.no-entry-anim { animation: none; }

/* --- Thread container -------------------------------- */

.thread-container {
  display: flex;
  flex-direction: column;
  gap: 0;
}

.thread-exchange {
  display: flex;
  flex-direction: column;
}

.thread-exchange + .thread-exchange {
  margin-top: 2rem;
  padding-top: 2.5rem;
  border-top: 1px solid var(--border);
}

/* Sent letter (user's outgoing card) */

.sent-letter {
  position: relative;
}

.sent-letter::before {
  content: 'Your letter';
  display: block;
  font-family: var(--font-ui);
  font-size: 0.65rem;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  color: var(--ink-meta);
  opacity: 0.65;
  margin-bottom: 1.4rem;
}

.sent-letter-header {
  display: flex;
  justify-content: space-between;
  align-items: baseline;
  padding-bottom: 0.85rem;
  margin-bottom: 1.4rem;
  border-bottom: 1px solid var(--rule);
  font-family: var(--font-literary-ui);
  font-size: 0.8rem;
  color: var(--ink-meta);
  opacity: 0.85;
}

.sent-letter-body {
  font-family: var(--font-letter);
  font-size: 1.08rem;
  line-height: 1.88;
  color: var(--ink);
  white-space: pre-line;
  overflow-wrap: break-word;
}

/* Separator between sent and reply within an exchange */

.thread-sep {
  display: flex;
  align-items: center;
  justify-content: center;
  padding: 1.75rem 0;
  gap: 0.7rem;
}

.thread-sep::before,
.thread-sep::after {
  content: '';
  flex: 1;
  height: 1px;
  background: var(--rule);
}

.thread-sep-dot {
  width: 3px;
  height: 3px;
  border-radius: 50%;
  background: var(--ink-meta);
  opacity: 0.45;
}

/* --- Write back compose ------------------------------ */

@keyframes writeBackAppear {
  from { opacity: 0; transform: translateY(8px); }
  to   { opacity: 1; transform: translateY(0); }
}

.write-back-compose.entering {
  animation: writeBackAppear 0.5s ease-out both;
}

.write-back-stationery {
  padding-bottom: 0;
}

.write-back-header {
  display: flex;
  align-items: baseline;
  gap: 1rem;
  padding-bottom: 0.9rem;
  border-bottom: 1px solid var(--border);
  margin-bottom: 1.5rem;
}

.write-back-to {
  font-family: var(--font-literary-ui);
  font-size: 1rem;
  color: var(--ink);
}

/* --- Write back button ------------------------------- */

.write-back-btn {
  display: block;
  margin: 2rem auto 0;
  padding: 0.72rem 2.6rem;
  background: transparent;
  border: 1px solid var(--amber);
  color: var(--amber);
  font-family: var(--font-ui);
  font-size: 0.72rem;
  font-weight: 400;
  letter-spacing: 0.15em;
  text-transform: uppercase;
  cursor: pointer;
  transition: background 0.22s, color 0.22s, transform 0.1s;
}

.write-back-btn:hover {
  background: var(--amber);
  color: var(--user-paper);
}

.write-back-btn:active { transform: translateY(1px); }

.guest-save-prompt {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 0.7rem;
  text-align: center;
  padding: 1.4rem 0;
  margin-top: 0.5rem;
  border-top: 1px solid var(--rule);
}

.guest-save-prompt p {
  font-family: var(--font-ui);
  font-size: 0.72rem;
  letter-spacing: 0.05em;
  color: var(--ink-meta);
  text-transform: uppercase;
}

.reply-paper {
  padding: 3rem 3.5rem 3.5rem;
  background-color: #F7F1E1;
  background-image:
    radial-gradient(ellipse at 14% 8%,  rgba(219, 196, 165, 0.30) 0%, transparent 52%),
    radial-gradient(ellipse at 86% 84%, rgba(132, 89,  43,  0.06) 0%, transparent 48%),
    repeating-linear-gradient(
      -48deg,
      transparent 0px,
      transparent 22px,
      rgba(129, 117, 75, 0.016) 22px,
      rgba(129, 117, 75, 0.016) 23px
    ),
    repeating-linear-gradient(
      40deg,
      transparent 0px,
      transparent 30px,
      rgba(129, 117, 75, 0.009) 30px,
      rgba(129, 117, 75, 0.009) 31px
    );
  border-color: rgba(132, 89, 43, 0.18);
  box-shadow:
    0 2px 6px  rgba(68, 45, 28, 0.12),
    0 8px 32px rgba(68, 45, 28, 0.16),
    0 30px 72px rgba(68, 45, 28, 0.20),
    inset 0 0 90px rgba(219, 196, 165, 0.10),
    inset 0 1px 0  rgba(255, 255, 255, 0.60),
    inset 0 -1px 0 rgba(68, 45, 28, 0.04);
}

.reply-header {
  display: flex;
  justify-content: space-between;
  align-items: flex-start;
  margin-bottom: 1.8rem;
  padding-bottom: 0.8rem;
  border-bottom: 1px solid rgba(129, 117, 75, 0.20);
}

.reply-date-line {
  text-align: right;
  font-family: var(--font-literary-ui);
  font-style: italic;
  font-size: 0.88rem;
  color: var(--ink-warm);
  flex-shrink: 0;
  padding-left: 1rem;
}

.reply-address-block {
  display: flex;
  flex-direction: column;
  gap: 0.14rem;
  font-family: var(--font-literary-ui);
  font-size: 0.78rem;
  font-style: italic;
  color: var(--ink-meta);
  opacity: 0.85;
}

.reply-salutation {
  font-family: var(--font-letter);
  font-size: 1.12rem;
  color: var(--ink);
  margin-bottom: 1.3rem;
}

.reply-body {
  font-family: var(--font-letter);
  font-size: 1.1rem;
  line-height: 1.9;
  color: var(--ink);
  white-space: pre-line;
  line-break: auto;
  overflow-wrap: break-word;
}

.reply-body.is-typing::after {
  content: '';
  display: inline-block;
  width: 1px;
  height: 1.05em;
  margin-left: 0.14em;
  background: var(--amber);
  vertical-align: -0.12em;
  animation: letterCursor 1.15s ease-in-out infinite;
}

@keyframes letterCursor {
  0%, 42% { opacity: 0.82; }
  58%, 100% { opacity: 0.12; }
}

.reply-sig {
  margin-top: 2.6rem;
  font-family: var(--font-letter);
  font-style: italic;
  font-size: 1.1rem;
  color: var(--ink-warm);
  transition: opacity 0.7s ease;
}

.reply-sig.awaiting-signature {
  opacity: 0;
}

.typing-skip {
  display: flex;
  align-items: baseline;
  justify-content: flex-end;
  gap: 0.65rem;
  margin-top: 1.25rem;
  color: var(--ink-meta);
  font-family: var(--font-literary-ui);
  font-size: 0.76rem;
  font-style: italic;
  opacity: 1;
  transition: opacity 0.28s ease;
}

.typing-skip.is-leaving {
  opacity: 0;
}

.typing-skip button {
  padding: 0;
  border: 0;
  border-bottom: 1px solid var(--accent-line);
  background: transparent;
  color: var(--ink-warm);
  font-family: var(--font-ui);
  font-size: 0.64rem;
  letter-spacing: 0.09em;
  text-transform: uppercase;
  cursor: pointer;
}

.typing-skip button:hover,
.typing-skip button:focus-visible {
  border-bottom-color: var(--amber);
  color: var(--amber);
}

@media (prefers-reduced-motion: reduce) {
  .reply-body.is-typing::after {
    animation: none;
  }
}

/* --- Read aloud -------------------------------------- */

.read-letter {
  margin-top: 1.25rem;
  padding: 1rem 0.15rem 0;
  border-top: 1px solid var(--border);
}

.read-letter-label {
  margin-bottom: 0.75rem;
  font-family: var(--font-literary-ui);
  font-size: 0.98rem;
  font-style: italic;
  color: var(--ink);
}

.read-letter-options {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1rem;
}

.read-letter-actions {
  display: flex;
  justify-content: flex-end;
  align-items: center;
  gap: 0.7rem;
  margin-top: 0.85rem;
}

.voice-choice {
  display: flex;
  flex-wrap: wrap;
  gap: 0.85rem;
}

.voice-choice label {
  display: inline-flex;
  align-items: center;
  gap: 0.38rem;
  font-family: var(--font-ui);
  font-size: 0.72rem;
  color: var(--ink-meta);
  cursor: pointer;
}

.voice-choice input {
  width: 0.8rem;
  height: 0.8rem;
  accent-color: var(--amber);
}

.emotion-choice {
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  color: var(--ink-meta);
  font-family: var(--font-ui);
  font-size: 0.7rem;
  letter-spacing: 0.04em;
}

.emotion-choice select {
  padding: 0.3rem 1.6rem 0.3rem 0.45rem;
  border: none;
  border-bottom: 1px solid var(--accent-line);
  border-radius: 0;
  background: transparent;
  color: var(--ink);
  font-family: var(--font-literary-ui);
  font-size: 0.92rem;
  cursor: pointer;
}

.emotion-choice select:focus {
  outline: none;
  border-bottom-color: var(--amber);
  box-shadow: 0 2px 0 -1px rgba(132, 89, 43, 0.30);
}

.read-aloud-btn {
  flex: 0 0 auto;
  padding: 0.5rem 1rem;
  border: 1px solid var(--border);
  background: transparent;
  color: var(--ink);
  font-family: var(--font-ui);
  font-size: 0.68rem;
  letter-spacing: 0.11em;
  text-transform: uppercase;
  cursor: pointer;
  transition: background 0.2s, border-color 0.2s;
}

.read-aloud-btn:hover {
  background: rgba(238, 223, 195, 0.50);
  border-color: var(--amber);
}

.read-aloud-btn:disabled {
  cursor: wait;
  opacity: 0.58;
}

.reading-action-btn {
  padding: 0.2rem 0;
  border: 0;
  border-bottom: 1px solid var(--border);
  background: transparent;
  color: var(--ink-meta);
  font-family: var(--font-ui);
  font-size: 0.63rem;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  cursor: pointer;
}

.reading-action-btn:hover:not(:disabled),
.reading-action-btn:focus-visible {
  border-bottom-color: var(--amber);
  color: var(--amber);
}

.reading-action-btn:disabled {
  border-bottom-color: transparent;
  cursor: default;
  opacity: 0.38;
}

.archive-read-controls {
  margin-top: 1.25rem;
}

.read-letter-status {
  min-height: 1.2rem;
  margin-top: 0.65rem;
  font-family: var(--font-literary-ui);
  font-size: 0.88rem;
  font-style: italic;
  color: var(--amber);
}

.letter-audio {
  display: block;
  width: 100%;
  height: 32px;
  margin-top: 0.35rem;
  opacity: 0.78;
  filter: sepia(0.32) saturate(0.72);
}

/* --- Archive ----------------------------------------- */

#archiveSection {
  margin: -2.5rem -1.5rem -5rem;
  padding: 2.5rem 1.5rem 5rem;
  background: var(--archive);
  min-height: 100vh;
}

@media (max-width: 480px) {
  #archiveSection { margin: -1.5rem -1rem -4rem; padding: 1.5rem 1rem 4rem; }
}

.archive-bar {
  display: flex;
  justify-content: space-between;
  align-items: baseline;
  margin-bottom: 2rem;
}

.archive-heading {
  font-family: var(--font-literary-ui);
  font-size: 1.35rem;
  font-weight: 400;
  font-style: italic;
  letter-spacing: 0.01em;
  color: var(--paper-ink);
}

#archiveSection .nav-btn         { color: var(--paper-muted); }
#archiveSection .nav-btn:hover   { color: var(--paper-ink); }

#archiveList {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(200px, 1fr));
  gap: 1.3rem;
}

/* Envelope card */
@keyframes envCardEnter {
  from { opacity: 0; transform: translateY(10px); }
  to   { opacity: 1; transform: translateY(0); }
}

.env-card {
  cursor: pointer;
  position: relative;
  background: var(--user-paper);
  border: 1px solid rgba(132, 89, 43, 0.22);
  box-shadow:
    0 1px 2px rgba(68, 45, 28, 0.15),
    0 3px 10px rgba(68, 45, 28, 0.18),
    0 10px 30px rgba(68, 45, 28, 0.14),
    inset 0 1px 0 rgba(255, 255, 255, 0.48);
  display: flex;
  flex-direction: column;
  min-height: 148px;
  transition: transform 0.22s, box-shadow 0.22s;
  animation: envCardEnter 0.4s ease-out both;
}
.env-card:nth-child(2) { animation-delay: 0.06s; }
.env-card:nth-child(3) { animation-delay: 0.12s; }
.env-card:nth-child(4) { animation-delay: 0.18s; }
.env-card:nth-child(5) { animation-delay: 0.24s; }
.env-card:nth-child(6) { animation-delay: 0.30s; }

.env-card:hover {
  transform: translateY(-4px);
  box-shadow:
    0 2px 4px rgba(68, 45, 28, 0.18),
    0 6px 18px rgba(68, 45, 28, 0.22),
    0 18px 44px rgba(68, 45, 28, 0.16),
    inset 0 1px 0 rgba(255, 255, 255, 0.48);
}

.loading-envelope {
  width: 100%;
  min-height: 142px;
  cursor: default;
  pointer-events: none;
  animation: envelopeTravel 4s ease-in-out infinite;
}

.loading-envelope:hover {
  transform: none;
  box-shadow:
    0 1px 2px rgba(68, 45, 28, 0.15),
    0 3px 10px rgba(68, 45, 28, 0.18),
    0 10px 30px rgba(68, 45, 28, 0.14),
    inset 0 1px 0 rgba(255, 255, 255, 0.48);
}

.loading-envelope:hover .env-lid {
  clip-path: polygon(0 0, 100% 0, 50% 100%);
}

.loading-envelope .env-lid {
  background: #C8A86A;
}

.loading-envelope .env-postmark {
  color: var(--olive);
  letter-spacing: 0.12em;
}

.loading-envelope .env-address {
  padding-bottom: 0.9rem;
}

.loading-envelope .env-to {
  max-width: 15ch;
  overflow-wrap: anywhere;
}

#archiveList.is-opening .env-card {
  animation: none;
  pointer-events: none;
  transition:
    opacity 0.38s ease,
    filter 0.38s ease,
    transform 0.42s cubic-bezier(0.16, 1, 0.3, 1),
    box-shadow 0.42s ease;
}

#archiveList.is-opening .env-card:not(.is-selected) {
  opacity: 0.2;
  filter: saturate(0.62);
  transform: scale(0.975);
}

#archiveList.is-opening .env-card.is-selected {
  z-index: 8;
  transform: translateY(-7px) scale(1.035);
  box-shadow:
    0 3px 7px rgba(68, 45, 28, 0.18),
    0 12px 28px rgba(68, 45, 28, 0.24),
    0 25px 54px rgba(68, 45, 28, 0.18),
    inset 0 1px 0 rgba(255, 255, 255, 0.48);
}

#archiveList.is-opening .env-card.is-selected.is-leaving {
  opacity: 0;
  transform: translateY(5px) scale(0.99);
  transition-duration: 0.18s;
}

/* Triangular flap */
.env-lid {
  height: 62px;
  flex-shrink: 0;
  background: var(--paper-fold);
  border-bottom: 1px solid var(--border);
  clip-path: polygon(0 0, 100% 0, 50% 100%);
  position: relative;
  z-index: 3;
  transform-origin: top center;
  transition:
    clip-path 0.32s cubic-bezier(0.4, 0, 0.2, 1),
    transform 0.32s cubic-bezier(0.4, 0, 0.2, 1),
    opacity 0.24s ease;
}

.env-card:hover .env-lid {
  clip-path: polygon(0 0, 100% 0, 50% 68%);
}

.env-card.is-flap-open .env-lid {
  clip-path: polygon(0 0, 100% 0, 50% 100%);
  transform: perspective(520px) rotateX(168deg) translateY(-2px);
  opacity: 0.82;
  z-index: 1;
  transition-duration: 0.5s;
}

.env-letter-edge {
  position: absolute;
  z-index: 2;
  left: 10%;
  right: 10%;
  top: 35px;
  height: 104px;
  border: 1px solid var(--border);
  background: var(--paper);
  box-shadow: 0 -2px 8px rgba(68, 45, 28, 0.08);
  opacity: 0;
  transform: translateY(28px) scaleY(0.62);
  transform-origin: bottom center;
  transition:
    opacity 0.24s ease,
    transform 0.68s cubic-bezier(0.16, 1, 0.3, 1);
  pointer-events: none;
  overflow: hidden;
}

.env-card.is-extracting .env-letter-edge {
  opacity: 1;
  transform: translateY(-58px) scaleY(1);
}

.env-paper-fold {
  position: absolute;
  inset: 50% 0 auto;
  border-top: 1px solid rgba(68, 45, 28, 0.10);
}

.env-retrieval {
  position: absolute;
  left: 0.5rem;
  right: 0.5rem;
  top: 1.05rem;
  color: var(--amber);
  font-family: var(--font-literary-ui);
  font-size: 0.72rem;
  font-style: italic;
  letter-spacing: 0.01em;
  text-align: center;
  opacity: 0;
  transform: translateY(3px);
  transition: opacity 0.3s ease 0.28s, transform 0.3s ease 0.28s;
}

.env-card.is-retrieving .env-retrieval {
  opacity: 0.9;
  transform: translateY(0);
}

.env-card.is-extracting::after {
  content: '';
  position: absolute;
  z-index: 3;
  left: -1px;
  right: -1px;
  bottom: -1px;
  height: 82px;
  border: 1px solid var(--border);
  border-top: 0;
  background: var(--user-paper);
  clip-path: polygon(0 15%, 50% 70%, 100% 15%, 100% 100%, 0 100%);
  pointer-events: none;
}

/* Address block */
.env-address {
  flex: 1;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  padding: 0.5rem 1rem 1.1rem;
  text-align: center;
  gap: 0.28rem;
  position: relative;
  z-index: 4;
}

.env-postmark {
  font-family: var(--font-ui);
  font-size: 0.6rem;
  letter-spacing: 0.09em;
  text-transform: uppercase;
  color: var(--ink-meta);
  margin-bottom: 0.22rem;
}

.env-to {
  font-family: var(--font-literary-ui);
  font-size: 1.05rem;
  color: var(--ink);
  line-height: 1.25;
}

.env-from {
  font-family: var(--font-literary-ui);
  font-style: italic;
  font-size: 0.88rem;
  color: var(--ink-warm);
}

.archive-status {
  font-family: var(--font-ui);
  font-size: 0.72rem;
  letter-spacing: 0.04em;
  color: var(--paper-muted);
  padding: 0.6rem 0.9rem;
  border: 1px solid var(--border);
  border-radius: 2px;
  margin-bottom: 1.5rem;
  grid-column: 1 / -1;
}

.archive-empty {
  font-family: var(--font-literary-ui);
  font-style: italic;
  color: var(--paper-muted);
  text-align: center;
  padding: 3rem 0;
  grid-column: 1 / -1;
  display: flex;
  flex-direction: column;
  gap: 0.55rem;
}

.archive-empty-note {
  font-size: 0.82rem;
  opacity: 0.6;
}

.archive-guest {
  display: flex;
  flex-direction: column;
  align-items: center;
  text-align: center;
  padding: 3.5rem 1rem;
  gap: 2rem;
  grid-column: 1 / -1;
}

.archive-guest-msg {
  font-family: var(--font-literary-ui);
  font-style: italic;
  color: var(--ink-warm);
  font-size: 1.05rem;
}

.archive-guest-actions {
  display: flex;
  gap: 1rem;
  flex-wrap: wrap;
  justify-content: center;
}

/* --- Correspondence view ----------------------------- */

@keyframes unfoldLetter {
  0%   { opacity: 0; transform: translateY(-18px) scaleY(0.74); }
  38%  { opacity: 1; transform: translateY(-7px) scaleY(0.9); }
  72%  { transform: translateY(1px) scaleY(1.012); }
  100% { opacity: 1; transform: translateY(0) scaleY(1); }
}

#corrExchange.unfolding {
  animation: unfoldLetter 0.9s cubic-bezier(0.16, 1, 0.3, 1) both;
  transform-origin: top center;
}

@media (prefers-reduced-motion: reduce) {
  .loading-envelope {
    animation: none;
  }

  #corrExchange.unfolding {
    animation-duration: 0.01ms;
  }

  .env-lid,
  .env-letter-edge,
  .env-retrieval {
    transition-duration: 0.01ms;
    transition-delay: 0s;
  }
}

.corr-nav {
  margin-bottom: 2.5rem;
}

#corrExchange {
  display: flex;
  flex-direction: column;
}

.corr-paper {
  padding: 2.5rem 3rem;
  box-shadow:
    0 1px 3px rgba(68, 45, 28, 0.10),
    0 5px 18px rgba(68, 45, 28, 0.14),
    0 16px 44px rgba(68, 45, 28, 0.16),
    inset 0 1px 0 rgba(255, 255, 255, 0.48);
}

.corr-paper-label {
  font-family: var(--font-ui);
  font-size: 0.67rem;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  color: var(--ink-meta);
  margin-bottom: 1.2rem;
}

.corr-to-line {
  font-family: var(--font-literary-ui);
  font-size: 0.95rem;
  color: var(--ink-meta);
  padding-bottom: 0.8rem;
  margin-bottom: 1.4rem;
  border-bottom: 1px solid var(--border);
}

.corr-body {
  font-family: var(--font-letter);
  font-size: 1.1rem;
  line-height: 1.9;
  color: var(--ink);
  white-space: pre-line;
  line-break: auto;
  overflow-wrap: break-word;
}

.letter-preview {
  font-family: var(--font-letter);
  line-height: 1.9;
  line-break: auto;
  overflow-wrap: break-word;
}

.corr-sep {
  display: flex;
  align-items: center;
  justify-content: center;
  padding: 2rem 0;
  gap: 0.8rem;
}

.corr-sep::before,
.corr-sep::after {
  content: '';
  flex: 1;
  height: 1px;
  background: var(--rule);
}

.corr-sep-dot {
  width: 4px;
  height: 4px;
  border-radius: 50%;
  background: var(--ink-meta);
}

/* --- Responsive -------------------------------------- */

@media (max-width: 480px) {
  #app { padding: 1.5rem 1rem 4rem; }
  .stationery { padding: 1.8rem 1.5rem; }
  .reply-paper { padding: 1.8rem 1.5rem; }
  .corr-paper { padding: 1.8rem 1.5rem; }
  .site-title { font-size: 1.5rem; }
  .read-letter-options { align-items: flex-start; flex-direction: column; }
  #archiveList { grid-template-columns: repeat(auto-fill, minmax(150px, 1fr)); gap: 1rem; }
}