:root {
  --bg-page: #f8fafc;
  --bg-surface: #ffffff;
  --bg-subtle: #f1f5f9;
  --bg-hover: #e2e8f0;
  --text-main: #0f172a;
  --text-secondary: #475569;
  --text-muted: #64748b;
  --border-color: #e2e8f0;
  --border-focus: #4f46e5;
  --primary: #4f46e5;
  --primary-hover: #4338ca;
  --primary-soft: #eef2ff;
  --primary-text: #ffffff;
  --success: #059669;
  --success-soft: #ecfdf5;
  --success-border: #a7f3d0;
  --warning: #d97706;
  --warning-soft: #fffbeb;
  --warning-border: #fde68a;
  --danger: #dc2626;
  --danger-soft: #fef2f2;
  --shadow-sm: 0 1px 2px 0 rgba(15, 23, 42, 0.05);
  --shadow-md:
    0 4px 6px -1px rgba(15, 23, 42, 0.07), 0 2px 4px -2px rgba(15, 23, 42, 0.05);
  --shadow-lg:
    0 12px 24px -4px rgba(15, 23, 42, 0.08),
    0 4px 8px -4px rgba(15, 23, 42, 0.04);
  --shadow-modal:
    0 20px 35px -5px rgba(15, 23, 42, 0.18),
    0 8px 14px -6px rgba(15, 23, 42, 0.1);
  --radius-sm: 8px;
  --radius-md: 12px;
  --radius-lg: 16px;
  --font-sans: "Inter", -apple-system, BlinkMacSystemFont, sans-serif;
  --font-display: "Plus Jakarta Sans", "Inter", sans-serif;
}

[data-theme="dark"] {
  --bg-page: #0b0f19;
  --bg-surface: #111827;
  --bg-subtle: #1e293b;
  --bg-hover: #334155;
  --text-main: #f8fafc;
  --text-secondary: #94a3b8;
  --text-muted: #64748b;
  --border-color: #1e293b;
  --border-focus: #6366f1;
  --primary: #6366f1;
  --primary-hover: #818cf8;
  --primary-soft: rgba(99, 102, 241, 0.14);
  --primary-text: #ffffff;
  --success: #34d399;
  --success-soft: rgba(16, 185, 129, 0.12);
  --success-border: rgba(52, 211, 153, 0.3);
  --warning: #fbbf24;
  --warning-soft: rgba(245, 158, 11, 0.12);
  --warning-border: rgba(251, 191, 36, 0.3);
  --danger: #f87171;
  --danger-soft: rgba(239, 68, 68, 0.12);
  --shadow-sm: 0 1px 2px 0 rgba(0, 0, 0, 0.3);
  --shadow-md: 0 4px 10px -1px rgba(0, 0, 0, 0.4);
  --shadow-lg: 0 12px 28px -4px rgba(0, 0, 0, 0.5);
  --shadow-modal: 0 24px 48px -8px rgba(0, 0, 0, 0.7);
}

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

html {
  scroll-behavior: smooth;
}

body {
  font-family: var(--font-sans);
  background-color: var(--bg-page);
  color: var(--text-main);
  line-height: 1.6;
  min-height: 100vh;
  display: flex;
  flex-direction: column;
  -webkit-font-smoothing: antialiased;
  transition:
    background-color 0.2s ease,
    color 0.2s ease;
}

.skip-link {
  position: absolute;
  top: -100px;
  left: 16px;
  background: var(--primary);
  color: #fff;
  padding: 8px 16px;
  border-radius: var(--radius-sm);
  z-index: 1000;
  text-decoration: none;
  font-weight: 600;
}
.skip-link:focus {
  top: 16px;
}

.navbar {
  background: var(--bg-surface);
  border-bottom: 1px solid var(--border-color);
  position: sticky;
  top: 0;
  z-index: 40;
}

.navbar-inner {
  max-width: 1200px;
  margin: 0 auto;
  padding: 14px 20px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 12px;
}

.brand {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  text-decoration: none;
  color: var(--text-main);
}

.brand-icon {
  width: 34px;
  height: 34px;
  border-radius: 9px;
  background: var(--primary);
  color: #fff;
  display: grid;
  place-items: center;
  font-family: var(--font-display);
  font-weight: 800;
  font-size: 0.95rem;
}

.brand-name {
  font-family: var(--font-display);
  font-weight: 700;
  font-size: 1.1rem;
  letter-spacing: -0.02em;
}

.nav-right {
  display: flex;
  align-items: center;
  gap: 10px;
}

.sync-badge {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  font-size: 0.75rem;
  font-weight: 500;
  color: var(--text-secondary);
  background: var(--bg-subtle);
  padding: 5px 10px;
  border-radius: 999px;
}

.sync-dot {
  width: 7px;
  height: 7px;
  border-radius: 50%;
  background: var(--success);
}

.container {
  max-width: 1200px;
  width: 100%;
  margin: 0 auto;
  padding: 32px 20px 72px;
  flex: 1;
}

.page-intro {
  text-align: center;
  max-width: 600px;
  margin: 28px auto 56px;
}

.page-intro h1 {
  font-family: var(--font-display);
  font-size: clamp(1.6rem, 3vw, 2.15rem);
  font-weight: 800;
  letter-spacing: -0.025em;
  line-height: 1.25;
  margin-bottom: 8px;
  color: var(--text-main);
}

.page-intro p {
  font-size: 0.95rem;
  color: var(--text-secondary);
}

.primary-card {
  background: var(--bg-surface);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-lg);
  box-shadow: var(--shadow-lg);
  padding: 28px;
  margin-bottom: 36px;
}

.primary-grid {
  display: grid;
  grid-template-columns: 1.35fr 1fr;
  gap: 28px;
  align-items: stretch;
}

.participants-column {
  display: flex;
  flex-direction: column;
  height: 100%;
}

.section-label-row {
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin-bottom: 8px;
  gap: 8px;
}

.field-label {
  font-weight: 600;
  font-size: 0.9rem;
  color: var(--text-main);
}

.counter-pill {
  font-size: 0.76rem;
  font-weight: 600;
  color: var(--primary);
  background: var(--primary-soft);
  padding: 2px 10px;
  border-radius: 999px;
}

.quick-input-group {
  display: flex;
  gap: 8px;
  margin-bottom: 10px;
}

.input-control,
.textarea-control,
.select-control {
  width: 100%;
  font-family: var(--font-sans);
  font-size: 0.92rem;
  color: var(--text-main);
  background: var(--bg-page);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-sm);
  padding: 10px 13px;
  transition:
    border-color 0.15s ease,
    box-shadow 0.15s ease,
    background-color 0.15s ease;
}

.input-control:focus,
.textarea-control:focus,
.select-control:focus {
  outline: none;
  background: var(--bg-surface);
  border-color: var(--border-focus);
  box-shadow: 0 0 0 3px var(--primary-soft);
}

.textarea-control {
  flex: 1;
  min-height: 200px;
  height: 100%;
  resize: none;
  line-height: 1.65;
}

.textarea-control::-webkit-scrollbar {
    width: 0;
}

.helper-bar {
  display: flex;
  align-items: center;
  justify-content: space-between;
  flex-wrap: wrap;
  gap: 8px;
  margin-top: 8px;
  font-size: 0.78rem;
  color: var(--text-muted);
}

.helper-links {
  display: flex;
  align-items: center;
  gap: 12px;
}

.text-link-btn {
  background: none;
  border: none;
  color: var(--text-secondary);
  font-family: var(--font-sans);
  font-size: 0.78rem;
  font-weight: 500;
  cursor: pointer;
  text-decoration: underline;
  text-underline-offset: 3px;
  padding: 2px 0;
}
.text-link-btn:hover {
  color: var(--primary);
}

.settings-column {
  display: flex;
  flex-direction: column;
  gap: 18px;
  background: var(--bg-page);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
  padding: 20px;
}

.segmented-control {
  display: grid;
  grid-template-columns: 1fr 1fr;
  background: var(--bg-subtle);
  padding: 4px;
  border-radius: var(--radius-sm);
  gap: 4px;
}

.segment-btn {
  font-family: var(--font-sans);
  font-size: 0.8rem;
  font-weight: 600;
  padding: 8px 10px;
  border: none;
  border-radius: 6px;
  background: transparent;
  color: var(--text-secondary);
  cursor: pointer;
  transition: all 0.15s ease;
}

.segment-btn.active {
  background: var(--bg-surface);
  color: var(--text-main);
  box-shadow: var(--shadow-sm);
}

.number-picker-box {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 12px;
  background: var(--bg-surface);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-sm);
  padding: 10px 14px;
}

.number-picker-info {
  display: flex;
  flex-direction: column;
}

.number-picker-sub {
  font-size: 0.76rem;
  color: var(--text-muted);
}

.stepper {
  display: inline-flex;
  align-items: center;
  gap: 4px;
}

.stepper-btn {
  width: 34px;
  height: 34px;
  border-radius: 6px;
  border: 1px solid var(--border-color);
  background: var(--bg-subtle);
  color: var(--text-main);
  font-size: 1.05rem;
  font-weight: 600;
  cursor: pointer;
  display: grid;
  place-items: center;
  transition: background-color 0.15s ease;
}
.stepper-btn:hover {
  background: var(--bg-hover);
}

.stepper-input {
  width: 52px;
  height: 34px;
  text-align: center;
  font-family: var(--font-sans);
  font-size: 1rem;
  font-weight: 700;
  color: var(--text-main);
  background: transparent;
  border: 1px solid transparent;
  border-radius: 6px;
}
.stepper-input:focus {
  outline: none;
  border-color: var(--border-focus);
  background: var(--bg-page);
}

.balance-preview {
  padding: 12px 14px;
  border-radius: var(--radius-sm);
  font-size: 0.82rem;
  line-height: 1.45;
  border: 1px solid var(--border-color);
  background: var(--bg-surface);
  display: flex;
  align-items: flex-start;
  gap: 10px;
}

.balance-preview.is-even {
  background: var(--success-soft);
  border-color: var(--success-border);
}

.balance-preview.is-uneven {
  background: var(--warning-soft);
  border-color: var(--warning-border);
}

.balance-dot {
  width: 20px;
  height: 20px;
  border-radius: 50%;
  display: grid;
  place-items: center;
  font-size: 0.75rem;
  font-weight: 700;
  flex-shrink: 0;
  margin-top: 1px;
}

.balance-preview.is-even .balance-dot {
  background: var(--success);
  color: #fff;
}

.balance-preview.is-uneven .balance-dot {
  background: var(--warning);
  color: #fff;
}

.balance-title {
  font-weight: 600;
  color: var(--text-main);
  display: block;
  margin-bottom: 2px;
}

.balance-desc {
  color: var(--text-secondary);
}

.secondary-prefs {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 10px;
  padding-top: 4px;
  border-top: 1px solid var(--border-color);
}

.pref-item {
  display: flex;
  flex-direction: column;
  gap: 4px;
}

.pref-label {
  font-size: 0.75rem;
  font-weight: 500;
  color: var(--text-secondary);
}

.checkbox-inline {
  display: flex;
  align-items: center;
  gap: 8px;
  font-size: 0.82rem;
  color: var(--text-main);
  cursor: pointer;
  height: 38px;
  padding: 0 10px;
  border-radius: var(--radius-sm);
  background: var(--bg-surface);
  border: 1px solid var(--border-color);
}

.checkbox-inline input {
  accent-color: var(--primary);
  width: 15px;
  height: 15px;
}

.icon-svg {
  width: 16px;
  height: 16px;
  stroke: currentColor;
  stroke-width: 2;
  stroke-linecap: round;
  stroke-linejoin: round;
  fill: none;
  flex-shrink: 0;
  display: inline-block;
  vertical-align: middle;
}
.icon-svg-sm {
  width: 14px;
  height: 14px;
}
.icon-svg-lg {
  width: 20px;
  height: 20px;
}
.icon-svg-xl {
  width: 24px;
  height: 24px;
}

.btn {
  font-family: var(--font-sans);
  font-size: 0.88rem;
  font-weight: 600;
  padding: 10px 16px;
  border-radius: var(--radius-sm);
  border: 1px solid var(--border-color);
  background: var(--bg-surface);
  color: var(--text-main);
  cursor: pointer;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  transition: all 0.15s ease;
  text-decoration: none;
}

.btn:hover {
  background: var(--bg-subtle);
}

.btn-primary {
  background: var(--primary);
  color: var(--primary-text);
  border-color: var(--primary);
  font-size: 0.96rem;
  font-weight: 600;
  padding: 13px 20px;
  box-shadow: 0 4px 12px rgba(79, 70, 229, 0.25);
  width: 100%;
}

.btn-primary:hover {
  background: var(--primary-hover);
  border-color: var(--primary-hover);
  transform: translateY(-1px);
}

.btn-sm {
  padding: 6px 12px;
  font-size: 0.8rem;
}

.btn-warning {
  background: var(--warning);
  color: #fff;
  border-color: var(--warning);
}
.btn-warning:hover {
  filter: brightness(0.95);
  background: var(--warning);
}

.btn-danger {
  background: var(--danger);
  color: #fff;
  border-color: var(--danger);
}
.btn-danger:hover {
  filter: brightness(0.95);
  background: var(--danger);
}

.btn-confirm-primary {
  background: var(--primary);
  color: #fff;
  border-color: var(--primary);
}
.btn-confirm-primary:hover {
  background: var(--primary-hover);
  border-color: var(--primary-hover);
}

.results-wrapper {
  scroll-margin-top: 76px;
}

.results-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  flex-wrap: wrap;
  gap: 12px;
  margin-bottom: 16px;
}

.results-title-group {
  display: flex;
  align-items: center;
  gap: 10px;
  flex-wrap: wrap;
}

.results-title {
  font-family: var(--font-display);
  font-size: 1.25rem;
  font-weight: 700;
  letter-spacing: -0.02em;
}

.time-pill {
  font-size: 0.76rem;
  color: var(--text-muted);
  background: var(--bg-subtle);
  padding: 4px 10px;
  border-radius: 999px;
}

.results-actions {
  display: flex;
  align-items: center;
  gap: 8px;
  flex-wrap: wrap;
}

.uneven-result-notice {
  background: var(--warning-soft);
  border: 1px solid var(--warning-border);
  border-radius: var(--radius-md);
  padding: 12px 16px;
  margin-bottom: 18px;
  display: none;
  align-items: center;
  justify-content: space-between;
  gap: 12px;
  font-size: 0.85rem;
}

.uneven-result-notice.visible {
  display: flex;
}

.groups-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(255px, 1fr));
  gap: 16px;
}

.group-card {
  background: var(--bg-surface);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
  box-shadow: var(--shadow-sm);
  display: flex;
  flex-direction: column;
  overflow: hidden;
  transition:
    box-shadow 0.2s ease,
    border-color 0.2s ease;
  animation: fadeUp 0.25s ease both;
}

.group-card:hover {
  box-shadow: var(--shadow-md);
}

.group-card.is-smaller {
  border-color: var(--warning-border);
}

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

.group-card-head {
  padding: 12px 16px;
  background: var(--bg-subtle);
  border-bottom: 1px solid var(--border-color);
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 8px;
}

.group-card.is-smaller .group-card-head {
  background: var(--warning-soft);
}

.group-title-input {
  font-family: var(--font-display);
  font-weight: 700;
  font-size: 0.95rem;
  color: var(--text-main);
  background: transparent;
  border: 1px solid transparent;
  border-radius: 6px;
  padding: 2px 6px;
  margin-left: -6px;
  width: 100%;
}
.group-title-input:hover,
.group-title-input:focus {
  outline: none;
  background: var(--bg-surface);
  border-color: var(--border-color);
}

.member-count-tag {
  font-size: 0.74rem;
  font-weight: 600;
  color: var(--text-secondary);
  background: var(--bg-surface);
  padding: 2px 8px;
  border-radius: 999px;
  border: 1px solid var(--border-color);
  white-space: nowrap;
}

.member-list {
  list-style: none;
  padding: 12px 16px;
  display: flex;
  flex-direction: column;
  gap: 6px;
  flex: 1;
}

.member-row {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 8px;
  padding: 7px 10px;
  border-radius: 6px;
  background: var(--bg-page);
  font-size: 0.88rem;
  font-weight: 500;
}

.member-info {
  display: flex;
  align-items: center;
  gap: 8px;
  min-width: 0;
}

.member-idx {
  font-size: 0.74rem;
  font-weight: 600;
  color: var(--text-muted);
  width: 20px;
  flex-shrink: 0;
}

.member-name {
  overflow: hidden;
  text-overflow: ellipsis;
  white-space: nowrap;
}

.leader-pill {
  font-size: 0.68rem;
  font-weight: 600;
  color: var(--primary);
  background: var(--primary-soft);
  padding: 2px 7px;
  border-radius: 999px;
  flex-shrink: 0;
}

.history-details {
  margin-top: 32px;
  background: var(--bg-surface);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
  overflow: hidden;
}

.history-summary {
  padding: 14px 18px;
  font-weight: 600;
  font-size: 0.88rem;
  color: var(--text-secondary);
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: space-between;
  user-select: none;
}
.history-summary:hover {
  background: var(--bg-subtle);
}

.history-body {
  padding: 16px 18px;
  border-top: 1px solid var(--border-color);
}

.history-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(220px, 1fr));
  gap: 10px;
  margin-top: 10px;
}

.history-card {
  padding: 10px 12px;
  border: 1px solid var(--border-color);
  border-radius: var(--radius-sm);
  background: var(--bg-page);
  font-size: 0.8rem;
  display: flex;
  flex-direction: column;
  gap: 6px;
}

.modal-backdrop {
  position: fixed;
  inset: 0;
  background: rgba(15, 23, 42, 0.55);
  backdrop-filter: blur(3px);
  z-index: 100;
  display: none;
  place-items: center;
  padding: 20px;
  animation: fadeIn 0.15s ease;
}

.modal-backdrop.open {
  display: grid;
}

@keyframes fadeIn {
  from {
    opacity: 0;
  }
  to {
    opacity: 1;
  }
}

.modal-card {
  background: var(--bg-surface);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-lg);
  box-shadow: var(--shadow-modal);
  max-width: 460px;
  width: 100%;
  padding: 24px;
  animation: scaleIn 0.18s ease;
}

@keyframes scaleIn {
  from {
    opacity: 0;
    transform: scale(0.96) translateY(6px);
  }
  to {
    opacity: 1;
    transform: scale(1) translateY(0);
  }
}

.modal-icon-badge {
  width: 44px;
  height: 44px;
  border-radius: 12px;
  background: var(--warning-soft);
  border: 1px solid var(--warning-border);
  color: var(--warning);
  display: grid;
  place-items: center;
  font-size: 1.25rem;
  font-weight: 700;
  margin-bottom: 14px;
}
.modal-icon-badge.badge-danger {
  background: var(--danger-soft);
  border-color: rgba(220, 38, 38, 0.3);
  color: var(--danger);
}
.modal-icon-badge.badge-primary {
  background: var(--primary-soft);
  border-color: rgba(79, 70, 229, 0.3);
  color: var(--primary);
}

.modal-title {
  font-family: var(--font-display);
  font-size: 1.15rem;
  font-weight: 700;
  margin-bottom: 8px;
  color: var(--text-main);
}

.modal-desc {
  font-size: 0.9rem;
  color: var(--text-secondary);
  margin-bottom: 14px;
}

.modal-breakdown-box {
  background: var(--bg-page);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-sm);
  padding: 12px 14px;
  font-size: 0.85rem;
  color: var(--text-main);
  margin-bottom: 20px;
}

.modal-actions {
  display: flex;
  justify-content: flex-end;
  gap: 10px;
}

.toast-container {
  position: fixed;
  bottom: 20px;
  right: 20px;
  z-index: 90;
  display: flex;
  flex-direction: column;
  gap: 8px;
  max-width: 340px;
  pointer-events: none;
}

.toast {
  pointer-events: auto;
  background: var(--bg-surface);
  color: var(--text-main);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-sm);
  box-shadow: var(--shadow-lg);
  padding: 11px 14px;
  font-size: 0.83rem;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 10px;
}

.site-footer {
  border-top: 1px solid var(--border-color);
  background: var(--bg-surface);
  padding: 20px;
  margin-top: auto;
  text-align: center;
  font-size: 0.8rem;
  color: var(--text-muted);
}

@keyframes highlightSection {
  0% {
    box-shadow: 0 0 0 0 rgba(79, 70, 229, 0.35);
  }
  70% {
    box-shadow: 0 0 0 10px rgba(79, 70, 229, 0);
  }
  100% {
    box-shadow: 0 0 0 0 rgba(79, 70, 229, 0);
  }
}

.results-flash {
  border-radius: var(--radius-md);
  animation: highlightSection 0.9s ease-out;
}

@media (max-width: 768px) {
  .primary-grid {
    grid-template-columns: 1fr;
  }
  .primary-card {
    padding: 20px;
  }
  .secondary-prefs {
    grid-template-columns: 1fr;
  }
}

@media print {
  .navbar,
  .primary-card,
  .results-actions,
  .history-details,
  .site-footer,
  .toast-container,
  .modal-backdrop {
    display: none !important;
  }
}