/* ============================================
   分帳趣 — 紙本帳簿風格
   平面紙底・髮絲分隔線・等寬數字・墨色為主
   綠與紅只用於金額語意（應收 / 應付）
   ============================================ */
* { box-sizing: border-box; margin: 0; padding: 0; }

:root {
  --paper: #f5f3ee;
  --card: #fbfaf6;
  --ink: #26231d;
  --sub: #8a8375;
  --rule: rgba(38, 35, 29, .14);
  --rule-strong: rgba(38, 35, 29, .6);
  --fill: rgba(38, 35, 29, .05);
  --green: #3d7a55;
  --red: #b3564d;
  --mono: ui-monospace, "SF Mono", SFMono-Regular, Menlo, Consolas, monospace;
}

@media (prefers-color-scheme: dark) {
  :root {
    --paper: #191813;
    --card: #201f1a;
    --ink: #e8e4da;
    --sub: #8f897b;
    --rule: rgba(232, 228, 218, .13);
    --rule-strong: rgba(232, 228, 218, .5);
    --fill: rgba(232, 228, 218, .06);
    --green: #8fbf9f;
    --red: #cf8e85;
  }
}

html { -webkit-text-size-adjust: 100%; scrollbar-width: none; }
html::-webkit-scrollbar, body::-webkit-scrollbar { display: none; }

body {
  font-family: -apple-system, BlinkMacSystemFont, "PingFang TC", "Noto Sans TC",
    "Microsoft JhengHei", "Segoe UI", sans-serif;
  background: var(--paper);
  color: var(--ink);
  line-height: 1.6;
  min-height: 100dvh;
}

.hidden { display: none !important; }
.visually-hidden {
  position: absolute;
  width: 1px; height: 1px;
  overflow: hidden;
  clip: rect(0 0 0 0);
}
button { font-family: inherit; color: var(--ink); }
svg { display: block; }

.container {
  max-width: 620px;
  margin: 0 auto;
  padding: 8px 20px;
  padding-bottom: calc(120px + env(safe-area-inset-bottom));
}

/* ===== 頁首 ===== */
.group-header {
  max-width: 620px;
  margin: 0 auto;
  padding: 26px 20px 0;
  padding-top: calc(26px + env(safe-area-inset-top));
}
.overline {
  display: block;
  font-size: .7rem;
  font-weight: 600;
  letter-spacing: .3em;
  color: var(--sub);
}
.group-header h1 {
  font-size: 1.5rem;
  font-weight: 700;
  letter-spacing: .02em;
  overflow: hidden;
  text-overflow: ellipsis;
  white-space: nowrap;
  padding-bottom: 12px;
  border-bottom: 2px solid var(--rule-strong);
}

/* ===== 摘要／統計數字列 ===== */
.summary-wrap {
  max-width: 620px;
  margin: 0 auto;
  padding: 0 20px;
}
.stat-strip {
  display: flex;
  border-bottom: 1px solid var(--rule);
  margin-bottom: 8px;
}
.stat {
  flex: 1;
  padding: 12px 0 10px;
  min-width: 0;
}
.stat + .stat { border-left: 1px solid var(--rule); padding-left: 16px; }
.stat-label {
  display: block;
  font-size: .68rem;
  font-weight: 600;
  letter-spacing: .12em;
  color: var(--sub);
}
.stat-value {
  display: block;
  font-family: var(--mono);
  font-size: 1.1rem;
  font-weight: 600;
  font-variant-numeric: tabular-nums;
  overflow: hidden;
  text-overflow: ellipsis;
  white-space: nowrap;
}
.stat-value.positive { color: var(--green); }
.stat-value.negative { color: var(--red); }

/* ===== 區塊（原卡片改為平面段落） ===== */
.card {
  background: none;
  border: none;
  padding: 0;
  margin-bottom: 34px;
}
.card h2 {
  display: flex;
  align-items: center;
  gap: 12px;
  font-size: .74rem;
  font-weight: 700;
  letter-spacing: .22em;
  color: var(--sub);
  margin-bottom: 6px;
}
.card h2::after {
  content: '';
  flex: 1;
  height: 1px;
  background: var(--rule);
}

label {
  display: block;
  font-size: .8rem;
  font-weight: 600;
  letter-spacing: .06em;
  color: var(--sub);
  margin-bottom: 14px;
}

input:not([type="checkbox"]), select {
  display: block;
  width: 100%;
  margin-top: 6px;
  padding: 10px 12px;
  font-size: 1rem;
  font-weight: 500;
  font-family: inherit;
  color: var(--ink);
  background: none;
  border: 1px solid var(--rule);
  border-radius: 8px;
  outline: none;
  transition: border-color .15s;
  appearance: none;
  -webkit-appearance: none;
}
input:not([type="checkbox"]):focus, select:focus { border-color: var(--rule-strong); }
input::placeholder { color: var(--sub); opacity: .6; }
input[type="number"], input[type="date"] { font-family: var(--mono); font-size: .95rem; }
select {
  background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='12' height='8' viewBox='0 0 12 8'%3E%3Cpath d='M1 1l5 5 5-5' stroke='%238a8375' stroke-width='1.6' fill='none' stroke-linecap='round'/%3E%3C/svg%3E");
  background-repeat: no-repeat;
  background-position: right 12px center;
  padding-right: 36px;
}

.btn {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  width: 100%;
  padding: 12px;
  font-size: .95rem;
  font-weight: 600;
  letter-spacing: .08em;
  border: 1px solid transparent;
  border-radius: 8px;
  cursor: pointer;
  transition: opacity .12s, border-color .12s, color .12s, transform .08s;
}
.btn svg { width: 15px; height: 15px; }
.btn:active { transform: scale(.99); }
.btn-primary { background: var(--ink); color: var(--paper); }
.btn-primary:hover { opacity: .88; }
.btn-secondary { background: none; border-color: var(--rule-strong); color: var(--ink); }
.btn-secondary:hover { background: var(--fill); }
.btn-ghost { background: none; border-color: var(--rule); color: var(--sub); }
.btn-ghost:hover { color: var(--ink); border-color: var(--rule-strong); }
.btn-sm { width: auto; padding: 9px 18px; font-size: .88rem; }

/* ===== 篩選列與分類 ===== */
.filter-bar { margin-bottom: 4px; }
.filter-bar input[type="search"] { margin-top: 0; }
.filter-bar .chip-row { margin: 10px 0 0; }

.chip-row { display: flex; flex-wrap: wrap; gap: 2px 4px; margin-bottom: 16px; }
.chip {
  background: none;
  border: none;
  border-radius: 6px;
  padding: 4px 10px;
  font-size: .84rem;
  font-weight: 600;
  color: var(--sub);
  cursor: pointer;
  transition: background .12s, color .12s;
}
.chip:hover { color: var(--ink); }
.chip.active { background: var(--ink); color: var(--paper); }

/* ===== 分類色（線條圖示用） ===== */
.cat-food { color: #8a6b3c; }
.cat-transport { color: #4e7a96; }
.cat-lodging { color: #6f5f96; }
.cat-shopping { color: #a05c6b; }
.cat-fun { color: #5d8256; }
.cat-other { color: #7d786d; }
.cat-transfer { color: var(--sub); }

@media (prefers-color-scheme: dark) {
  .cat-food { color: #c9a86b; }
  .cat-transport { color: #85b0c9; }
  .cat-lodging { color: #a99ad1; }
  .cat-shopping { color: #cf8d9c; }
  .cat-fun { color: #93bd85; }
  .cat-other { color: #a19b8d; }
}

/* ===== 支出列表（帳簿分欄線） ===== */
.expense-list { list-style: none; }
.expense-day { list-style: none; }
.expense-date-header {
  display: flex;
  justify-content: space-between;
  align-items: baseline;
  font-size: .74rem;
  font-weight: 700;
  letter-spacing: .1em;
  color: var(--sub);
  margin-top: 26px;
  padding-bottom: 5px;
  border-bottom: 1.5px solid var(--rule-strong);
  font-variant-numeric: tabular-nums;
}
.expense-date-header span:last-child { font-family: var(--mono); letter-spacing: 0; }
.day-group { list-style: none; }
.expense-item {
  display: flex;
  align-items: center;
  gap: 12px;
  padding: 12px 0;
  border-bottom: 1px solid var(--rule);
  cursor: pointer;
  transition: background .12s;
}
.expense-item:hover { background: var(--fill); }
.expense-item.transfer { cursor: default; }
.expense-icon {
  width: 26px;
  height: 26px;
  display: flex;
  align-items: center;
  justify-content: center;
  flex-shrink: 0;
}
.expense-icon svg { width: 19px; height: 19px; }
.expense-info { flex: 1; min-width: 0; }
.expense-desc {
  font-weight: 600;
  overflow: hidden;
  text-overflow: ellipsis;
  white-space: nowrap;
}
.expense-meta {
  font-size: .76rem;
  color: var(--sub);
  overflow: hidden;
  text-overflow: ellipsis;
  white-space: nowrap;
}
.expense-amount {
  font-family: var(--mono);
  font-weight: 600;
  font-size: .95rem;
  font-variant-numeric: tabular-nums;
  white-space: nowrap;
}
.expense-item.transfer .expense-amount { color: var(--sub); }
.expense-del {
  background: none;
  border: none;
  color: var(--sub);
  cursor: pointer;
  padding: 6px 2px 6px 6px;
  opacity: .4;
  transition: opacity .12s, color .12s;
}
.expense-del svg { width: 14px; height: 14px; }
.expense-del:hover { opacity: 1; color: var(--red); }

.empty-hint {
  text-align: center;
  color: var(--sub);
  font-size: .9rem;
  padding: 52px 20px 36px;
}

/* ===== 結算 / 成員 ===== */
.balance-list, .settlement-list, .member-list { list-style: none; }
.balance-list li, .member-list li {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 12px 0;
  border-bottom: 1px solid var(--rule);
}
.balance-amount {
  font-family: var(--mono);
  font-variant-numeric: tabular-nums;
  font-weight: 600;
  font-size: .92rem;
}
.balance-amount.positive { color: var(--green); }
.balance-amount.negative { color: var(--red); }
.balance-amount.zero { color: var(--sub); font-weight: 500; }

.settlement-list li {
  display: flex;
  align-items: center;
  gap: 10px;
  padding: 13px 0;
  border-bottom: 1px solid var(--rule);
  flex-wrap: wrap;
  font-weight: 600;
}
.settle-arrow { color: var(--sub); }
.settle-amount {
  margin-left: auto;
  font-family: var(--mono);
  font-weight: 600;
  font-variant-numeric: tabular-nums;
}
.settle-done {
  display: inline-flex;
  align-items: center;
  gap: 5px;
  background: none;
  color: var(--ink);
  border: 1px solid var(--rule-strong);
  border-radius: 6px;
  padding: 3px 10px;
  font-size: .78rem;
  font-weight: 600;
  cursor: pointer;
  transition: background .12s;
}
.settle-done svg { width: 12px; height: 12px; }
.settle-done:hover { background: var(--fill); }

.member-name-row { display: flex; align-items: center; gap: 10px; font-weight: 600; }
.member-tag {
  font-size: .66rem;
  font-weight: 700;
  letter-spacing: .08em;
  border: 1px solid var(--rule-strong);
  border-radius: 4px;
  padding: 0 7px;
  color: var(--sub);
}
.member-del {
  background: none;
  border: none;
  color: var(--sub);
  cursor: pointer;
  padding: 6px 2px 6px 8px;
  opacity: .5;
  transition: opacity .12s, color .12s;
}
.member-del svg { width: 13px; height: 13px; }
.member-del:hover { opacity: 1; color: var(--red); }

.inline-form { display: flex; gap: 10px; margin-top: 16px; }
.inline-form input { margin-top: 0; flex: 1; }

.hint { font-size: .78rem; color: var(--sub); margin: 4px 0 6px; }
.hint-block {
  font-size: .84rem;
  color: var(--sub);
  background: var(--fill);
  border-radius: 8px;
  padding: 9px 13px;
  margin-bottom: 16px;
  font-variant-numeric: tabular-nums;
}

/* ===== 統計 ===== */
.stats-head { margin: 4px 0 2px; }
.stats-head select { margin-top: 0; font-weight: 600; }
#tab-stats .stat-strip { border-top: none; margin-bottom: 26px; }

.bar-list { list-style: none; }
.bar-list li { padding: 11px 0; border-bottom: 1px solid var(--rule); }
.bar-row {
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: 10px;
  margin-bottom: 7px;
}
.bar-name {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  font-weight: 600;
  font-size: .9rem;
}
.bar-icon {
  width: 20px;
  height: 20px;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  flex-shrink: 0;
}
.bar-icon svg { width: 15px; height: 15px; }
.bar-val {
  font-family: var(--mono);
  font-variant-numeric: tabular-nums;
  font-weight: 600;
  font-size: .9rem;
  white-space: nowrap;
}
.bar-val em {
  font-style: normal;
  font-weight: 500;
  font-size: .76rem;
  color: var(--sub);
  margin-left: 4px;
}
.bar-sub {
  font-size: .74rem;
  color: var(--sub);
  margin-top: 5px;
  font-variant-numeric: tabular-nums;
}
.bar-track {
  height: 3px;
  background: var(--fill);
  overflow: hidden;
}
.bar-fill {
  height: 100%;
  background: var(--ink);
  transition: width .3s ease;
}

#btn-export { margin-top: 18px; }

/* ===== 新增按鈕與底部導覽 ===== */
.fab {
  position: fixed;
  right: 18px;
  bottom: calc(74px + env(safe-area-inset-bottom));
  width: 52px;
  height: 52px;
  display: flex;
  align-items: center;
  justify-content: center;
  border-radius: 14px;
  border: none;
  background: var(--ink);
  color: var(--paper);
  box-shadow: 0 6px 20px rgba(0, 0, 0, .22);
  cursor: pointer;
  z-index: 20;
  transition: opacity .12s, transform .1s;
}
.fab svg { width: 21px; height: 21px; }
.fab:hover { opacity: .88; }
.fab:active { transform: scale(.95); }

.tab-bar {
  position: fixed;
  left: 0;
  right: 0;
  bottom: 0;
  display: flex;
  background: var(--card);
  border-top: 1px solid var(--rule);
  padding: 0 12px calc(4px + env(safe-area-inset-bottom));
  z-index: 15;
}
.tab-btn {
  flex: 1;
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 2px;
  padding: 9px 0 6px;
  background: none;
  border: none;
  border-top: 2px solid transparent;
  margin-top: -1px;
  color: var(--sub);
  cursor: pointer;
  transition: color .12s, border-color .12s;
}
.tab-btn svg { width: 20px; height: 20px; }
.tab-btn span {
  font-size: .66rem;
  font-weight: 600;
  letter-spacing: .1em;
}
.tab-btn.active {
  color: var(--ink);
  border-top-color: var(--ink);
}

/* ===== Modal ===== */
.modal {
  position: fixed;
  inset: 0;
  background: rgba(20, 18, 14, .5);
  display: flex;
  align-items: flex-end;
  justify-content: center;
  z-index: 50;
  animation: fade-in .15s ease;
}
.modal-card {
  background: var(--card);
  width: 100%;
  max-width: 560px;
  max-height: 92dvh;
  overflow-y: auto;
  scrollbar-width: none;
  border-radius: 14px 14px 0 0;
  padding: 22px 22px calc(22px + env(safe-area-inset-bottom));
  animation: slide-up .24s cubic-bezier(.22, 1, .36, 1);
}
.modal-card::-webkit-scrollbar { display: none; }
.modal-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding-bottom: 10px;
  border-bottom: 2px solid var(--rule-strong);
  margin-bottom: 18px;
}
.modal-header h2 { font-size: 1.1rem; font-weight: 700; letter-spacing: .02em; }

.icon-btn {
  display: flex;
  align-items: center;
  justify-content: center;
  background: none;
  border: none;
  width: 32px;
  height: 32px;
  color: var(--sub);
  cursor: pointer;
  flex-shrink: 0;
  transition: color .12s;
}
.icon-btn svg { width: 16px; height: 16px; }
.icon-btn:hover { color: var(--ink); }

@keyframes fade-in { from { opacity: 0; } }
@keyframes slide-up { from { transform: translateY(48px); opacity: .3; } }

.row-2 { display: grid; grid-template-columns: 1fr 1fr; gap: 12px; }

.split-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: 10px;
}
.split-header label { margin-bottom: 0; }

.seg {
  display: flex;
  gap: 2px;
  border: 1px solid var(--rule);
  border-radius: 8px;
  padding: 2px;
}
.seg-btn {
  border: none;
  background: none;
  color: var(--sub);
  padding: 4px 12px;
  font-size: .82rem;
  font-weight: 600;
  border-radius: 6px;
  cursor: pointer;
  transition: background .12s, color .12s;
}
.seg-btn.active { background: var(--ink); color: var(--paper); }

.split-list {
  list-style: none;
  margin-bottom: 16px;
  border-top: 1.5px solid var(--rule-strong);
}
.split-list li {
  display: flex;
  align-items: center;
  gap: 12px;
  padding: 10px 2px;
  border-bottom: 1px solid var(--rule);
}
.split-list input[type="checkbox"] {
  width: 18px;
  height: 18px;
  margin: 0;
  accent-color: var(--ink);
  flex-shrink: 0;
}
.split-name { flex: 1; font-weight: 600; }
.split-amount-input {
  width: 110px !important;
  margin-top: 0 !important;
  text-align: right;
  padding: 6px 10px !important;
}
.split-amount-label {
  color: var(--sub);
  font-family: var(--mono);
  font-size: .88rem;
  font-weight: 500;
  min-width: 80px;
  text-align: right;
  font-variant-numeric: tabular-nums;
}

/* ===== Toast ===== */
.toast {
  position: fixed;
  left: 50%;
  bottom: calc(96px + env(safe-area-inset-bottom));
  transform: translateX(-50%);
  background: var(--ink);
  color: var(--paper);
  border-radius: 8px;
  padding: 10px 20px;
  font-size: .88rem;
  font-weight: 600;
  z-index: 100;
  max-width: 90vw;
  text-align: center;
  box-shadow: 0 6px 20px rgba(0, 0, 0, .2);
  animation: toast-in .2s cubic-bezier(.22, 1, .36, 1);
}
@keyframes toast-in { from { transform: translate(-50%, 12px); opacity: 0; } }

/* ===== 平板 / 桌面 ===== */
@media (min-width: 768px) {
  .container { max-width: 680px; }
  .group-header, .summary-wrap { max-width: 680px; }

  .tab-bar {
    position: sticky;
    top: 0;
    bottom: auto;
    max-width: 680px;
    margin: 0 auto;
    background: var(--paper);
    border-top: none;
    border-bottom: 1px solid var(--rule);
    padding: 0 20px;
  }
  .tab-btn {
    flex: 0 0 auto;
    flex-direction: row;
    gap: 7px;
    padding: 12px 16px 10px;
    border-top: none;
    border-bottom: 2px solid transparent;
    margin: 0 0 -1px;
  }
  .tab-btn svg { width: 16px; height: 16px; }
  .tab-btn span { font-size: .88rem; letter-spacing: .06em; }
  .tab-btn.active { border-bottom-color: var(--ink); }

  #view-group { display: flex; flex-direction: column; }
  #view-group .group-header { order: 0; width: 100%; }
  #view-group .summary-wrap { order: 1; width: 100%; }
  #view-group .tab-bar { order: 2; width: 100%; }
  #view-group .container { order: 3; padding-bottom: 60px; width: 100%; }

  .fab { bottom: 36px; right: calc(50% - 340px); }

  .modal { align-items: center; padding: 24px; }
  .modal-card { border-radius: 12px; max-height: 88vh; }
  @keyframes slide-up { from { transform: translateY(20px) scale(.98); opacity: 0; } }

  .toast { bottom: 48px; }
}

@media (min-width: 1100px) {
  .fab { right: calc(50% - 340px - 76px); }
}