/* ===== Design tokens ===== */
:root {
  --bg: #FAFAF7;
  --bg-elevated: #FFFFFF;
  --border: #E8E6DE;
  --text: #1A1D24;
  --text-secondary: #5C6066;
  --text-tertiary: #8B9A8C;
  --accent: #4A6FA5;
  --accent-soft: #4A6FA51A;
  --urgent: #C9694A;
  --urgent-soft: #C9694A1A;

  --font-ui: -apple-system, BlinkMacSystemFont, "Segoe UI", system-ui, sans-serif;
  --font-mono: ui-monospace, "SF Mono", "Cascadia Code", Consolas, monospace;

  --radius: 8px;
  --radius-sm: 5px;
  --sidebar-width: 240px;
}

@media (prefers-color-scheme: dark) {
  :root {
    --bg: #1A1D24;
    --bg-elevated: #232730;
    --border: #2E333D;
    --text: #EDEEF0;
    --text-secondary: #A4A9B2;
    --text-tertiary: #6E7681;
    --accent: #7B9FD4;
    --accent-soft: #7B9FD426;
    --urgent: #E08868;
    --urgent-soft: #E0886826;
  }
}

html[data-theme="light"] {
  --bg: #FAFAF7;
  --bg-elevated: #FFFFFF;
  --border: #E8E6DE;
  --text: #1A1D24;
  --text-secondary: #5C6066;
  --text-tertiary: #8B9A8C;
  --accent: #4A6FA5;
  --accent-soft: #4A6FA51A;
  --urgent: #C9694A;
  --urgent-soft: #C9694A1A;
}
html[data-theme="dark"] {
  --bg: #1A1D24;
  --bg-elevated: #232730;
  --border: #2E333D;
  --text: #EDEEF0;
  --text-secondary: #A4A9B2;
  --text-tertiary: #6E7681;
  --accent: #7B9FD4;
  --accent-soft: #7B9FD426;
  --urgent: #E08868;
  --urgent-soft: #E0886826;
}

* { box-sizing: border-box; }

html, body {
  margin: 0;
  padding: 0;
  height: 100%;
  background: var(--bg);
  color: var(--text);
  font-family: var(--font-ui);
  font-size: 15px;
  line-height: 1.5;
  -webkit-font-smoothing: antialiased;
}

button { font-family: inherit; cursor: pointer; }

/* ===== App shell ===== */
.app {
  display: flex;
  height: 100vh;
  overflow: hidden;
}

/* ===== Sidebar ===== */
.sidebar {
  width: var(--sidebar-width);
  flex-shrink: 0;
  background: var(--bg-elevated);
  border-right: 1px solid var(--border);
  display: flex;
  flex-direction: column;
  padding: 20px 0;
  transition: width 0.2s ease;
  overflow: hidden;
}

.sidebar.collapsed { width: 48px; }
.sidebar.collapsed .brand,
.sidebar.collapsed .nav-label,
.sidebar.collapsed .nav-item-count,
.sidebar.collapsed .settings-btn,
.sidebar.collapsed .nav-item span:first-child { display: none; }
.sidebar.collapsed .nav-item { justify-content: center; padding: 8px 0; }

.sidebar-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 0 20px 20px;
  min-width: 0;
}
.sidebar.collapsed .sidebar-header { padding: 0 0 20px; justify-content: center; }

.sidebar-header-right {
  display: flex;
  align-items: center;
  gap: 6px;
}

.brand { font-weight: 700; font-size: 17px; letter-spacing: -0.01em; }

.sync-indicator {
  font-size: 10px;
  color: var(--accent);
  transition: color 0.3s ease;
}
.sync-indicator.syncing { color: var(--text-tertiary); animation: pulse 1s ease-in-out infinite; }
.sync-indicator.error { color: var(--urgent); }

@keyframes pulse {
  0%, 100% { opacity: 1; }
  50% { opacity: 0.3; }
}

.sidebar-collapse-btn {
  background: none;
  border: none;
  color: var(--text-tertiary);
  padding: 2px 4px;
  display: flex;
  align-items: center;
  flex-shrink: 0;
}
.sidebar-collapse-btn:hover { color: var(--text-secondary); }

.nav-section { padding: 0 12px; margin-bottom: 16px; }

.nav-label {
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.06em;
  text-transform: uppercase;
  color: var(--text-tertiary);
  padding: 0 8px 6px;
  display: flex;
  align-items: center;
}

.nav-list { list-style: none; margin: 0; padding: 0; }

.nav-item {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 7px 8px;
  border-radius: var(--radius-sm);
  font-size: 14px;
  color: var(--text-secondary);
  cursor: pointer;
  transition: background 0.12s ease;
}
.nav-item:hover { background: var(--border); }
.nav-item.active { background: var(--accent-soft); color: var(--accent); font-weight: 600; }

.nav-item-count {
  font-family: var(--font-mono);
  font-size: 11px;
  color: var(--text-tertiary);
}
.nav-item.active .nav-item-count { color: var(--accent); }

.settings-btn {
  margin: auto 12px 0;
  background: none;
  border: none;
  text-align: left;
  padding: 8px;
  font-size: 13px;
  color: var(--text-tertiary);
  border-radius: var(--radius-sm);
}
.settings-btn:hover { background: var(--border); color: var(--text-secondary); }

/* ===== Main content ===== */
.main {
  flex: 1;
  display: flex;
  flex-direction: column;
  overflow-y: auto;
  padding: 0 32px 32px;
}

.topbar {
  display: flex;
  align-items: center;
  gap: 12px;
  padding: 20px 0 16px;
  position: sticky;
  top: 0;
  background: var(--bg);
  z-index: 5;
}

.search-input {
  flex: 1;
  max-width: 360px;
  padding: 8px 14px;
  border: 1px solid var(--border);
  border-radius: var(--radius);
  background: var(--bg-elevated);
  color: var(--text);
  font-size: 14px;
}
.search-input:focus { outline: 2px solid var(--accent); outline-offset: -1px; }

.topbar-controls { margin-left: auto; }

.sort-toggle {
  background: var(--bg-elevated);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 7px 12px;
  font-size: 13px;
  font-family: var(--font-mono);
  color: var(--text-secondary);
}
.sort-toggle:hover { border-color: var(--accent); color: var(--accent); }

.list-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding-bottom: 16px;
}

.list-title { font-size: 26px; font-weight: 700; letter-spacing: -0.015em; margin: 0; }

.add-task-btn {
  background: var(--accent);
  color: white;
  border: none;
  border-radius: var(--radius);
  padding: 9px 16px;
  font-size: 14px;
  font-weight: 600;
}
.add-task-btn:hover { opacity: 0.9; }

/* ===== Task list ===== */
.task-list { display: flex; flex-direction: column; }

.task-row {
  display: flex;
  align-items: flex-start;
  gap: 10px;
  padding: 7px 8px;
  border-bottom: 1px solid var(--border);
  cursor: pointer;
  transition: background 0.12s ease;
}
.task-row:hover { background: var(--bg-elevated); }

.task-checkbox {
  width: 18px;
  height: 18px;
  border-radius: 50%;
  border: 2px solid var(--text-tertiary);
  flex-shrink: 0;
  margin-top: 2px;
  display: flex;
  align-items: center;
  justify-content: center;
  background: none;
  padding: 0;
  transition: border-color 0.15s ease, background 0.15s ease;
}
.task-checkbox:hover { border-color: var(--accent); }
.task-checkbox svg { width: 10px; height: 10px; opacity: 0; transition: opacity 0.15s ease; }
.task-checkbox.checked { background: var(--accent); border-color: var(--accent); }
.task-checkbox.checked svg { opacity: 1; }

.task-body {
  flex: 1;
  min-width: 0;
  display: flex;
  align-items: baseline;
  gap: 8px;
}

.task-title {
  flex: 1;
  font-size: 14px;
  color: var(--text);
  white-space: normal;
  word-break: break-word;
  transition: color 0.3s ease;
}
.task-row.completing .task-title {
  color: var(--text-tertiary);
  text-decoration: line-through;
  text-decoration-color: var(--text-tertiary);
}
.task-row.completing { animation: rowFadeOut 0.5s ease 0.4s forwards; }
@keyframes rowFadeOut {
  to { opacity: 0; max-height: 0; padding-top: 0; padding-bottom: 0; margin: 0; }
}

.task-due {
  font-family: var(--font-mono);
  font-size: 11px;
  color: var(--text-tertiary);
  white-space: nowrap;
  flex-shrink: 0;
}
.task-due.overdue { color: var(--urgent); }

/* ===== Empty state ===== */
.empty-state {
  padding: 60px 0;
  text-align: center;
  color: var(--text-tertiary);
  font-size: 14px;
}

/* ===== Detail overlay ===== */
.detail-overlay {
  position: fixed;
  inset: 0;
  background: rgba(0,0,0,0.3);
  display: flex;
  justify-content: flex-end;
  z-index: 50;
}
.detail-overlay[hidden] { display: none; }

.detail-panel {
  width: 420px;
  max-width: 90vw;
  height: 100%;
  background: var(--bg-elevated);
  border-left: 1px solid var(--border);
  padding: 24px;
  overflow-y: auto;
}

.detail-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin-bottom: 20px;
}
.detail-heading { font-size: 19px; font-weight: 700; margin: 0; }
.detail-close-btn { background: none; border: none; font-size: 16px; color: var(--text-tertiary); padding: 4px; }
.detail-close-btn:hover { color: var(--text); }

.detail-field { margin-bottom: 16px; }
.detail-field-row { display: flex; align-items: center; gap: 10px; }
.detail-field-row .detail-label {
  font-size: 13px;
  color: var(--text-secondary);
  flex-shrink: 0;
  width: 70px;
}

.detail-title-input {
  width: 100%;
  font-size: 18px;
  font-weight: 600;
  border: none;
  border-bottom: 1px solid var(--border);
  padding: 6px 0;
  background: transparent;
  color: var(--text);
  resize: none;
  overflow: hidden;
  line-height: 1.4;
  min-height: 2em;
  word-break: break-word;
  font-family: var(--font-ui);
}
.detail-title-input:focus { border-bottom-color: var(--accent); outline: none; }

.detail-notes-display {
  min-height: 180px;
  font-size: 14px;
  font-family: var(--font-ui);
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
  padding: 10px;
  background: var(--bg);
  color: var(--text);
  white-space: pre-wrap;
  word-break: break-word;
  cursor: text;
  line-height: 1.5;
}
.detail-notes-display:hover { border-color: var(--accent); }
.detail-notes-placeholder { color: var(--text-tertiary); }

.notes-link { color: var(--accent); text-decoration: underline; }
.notes-link:hover { opacity: 0.8; }

.detail-notes-input {
  width: 100%;
  font-size: 14px;
  font-family: var(--font-ui);
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
  padding: 10px;
  background: var(--bg);
  color: var(--text);
  resize: vertical;
}
.detail-notes-input:focus { outline: 2px solid var(--accent); outline-offset: -1px; }

.detail-due-input,
.detail-list-select {
  flex: 1;
  font-size: 14px;
  font-family: var(--font-mono);
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
  padding: 6px 8px;
  background: var(--bg);
  color: var(--text);
}

.detail-clear-due-btn { background: none; border: none; color: var(--text-tertiary); font-size: 13px; padding: 4px; }
.detail-clear-due-btn:hover { color: var(--urgent); }

.detail-actions {
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin-top: 24px;
  padding-top: 16px;
  border-top: 1px solid var(--border);
}
.detail-actions-right { display: flex; gap: 8px; margin-left: auto; }

.detail-delete-btn {
  background: none;
  border: 1px solid var(--border);
  color: var(--urgent);
  border-radius: var(--radius-sm);
  padding: 8px 14px;
  font-size: 13px;
}
.detail-delete-btn:hover { background: var(--urgent-soft); border-color: var(--urgent); }

.detail-cancel-btn {
  background: none;
  border: 1px solid var(--border);
  color: var(--text-secondary);
  border-radius: var(--radius-sm);
  padding: 8px 14px;
  font-size: 13px;
}
.detail-cancel-btn:hover { background: var(--border); }

.detail-save-btn {
  background: var(--accent);
  border: none;
  color: white;
  border-radius: var(--radius-sm);
  padding: 8px 16px;
  font-size: 13px;
  font-weight: 600;
}
.detail-save-btn:hover { opacity: 0.9; }
.detail-save-btn:disabled { opacity: 0.6; cursor: default; }

/* ===== Settings panel ===== */
.settings-backdrop {
  display: none;
  position: fixed;
  inset: 0;
  background: rgba(0,0,0,0.3);
  z-index: 40;
}
.settings-backdrop.open { display: block; }

.settings-panel {
  position: fixed;
  top: 0;
  left: 0;
  width: 320px;
  max-width: 90vw;
  height: 100%;
  background: var(--bg-elevated);
  border-right: 1px solid var(--border);
  padding: 24px;
  overflow-y: auto;
  z-index: 45;
  transform: translateX(-100%);
  transition: transform 0.22s ease;
}
.settings-panel.open { transform: translateX(0); }

.settings-header { display: flex; align-items: center; justify-content: space-between; margin-bottom: 24px; }
.settings-heading { font-size: 19px; font-weight: 700; margin: 0; }
.settings-close-btn { background: none; border: none; font-size: 16px; color: var(--text-tertiary); padding: 4px; }
.settings-close-btn:hover { color: var(--text); }

.settings-section { margin-bottom: 28px; padding-bottom: 28px; border-bottom: 1px solid var(--border); }
.settings-section:last-of-type { border-bottom: none; }

.settings-section-header { display: flex; align-items: center; justify-content: space-between; margin-bottom: 12px; }

.settings-section-title {
  font-size: 13px;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.05em;
  color: var(--text-secondary);
  margin: 0 0 12px;
  font-family: var(--font-mono);
}
.settings-section-header .settings-section-title { margin: 0; }

.settings-hint { font-size: 12px; color: var(--text-tertiary); margin: -4px 0 10px; }

.settings-select {
  width: 100%;
  font-size: 14px;
  font-family: var(--font-ui);
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
  padding: 7px 10px;
  background: var(--bg);
  color: var(--text);
}

.settings-radio-group { display: flex; gap: 20px; }
.settings-radio-label { display: flex; align-items: center; gap: 6px; font-size: 14px; color: var(--text-secondary); cursor: pointer; }
.settings-radio-label input { accent-color: var(--accent); }

.sl-add-btn { background: none; border: 1px solid var(--border); border-radius: var(--radius-sm); padding: 4px 10px; font-size: 12px; color: var(--accent); }
.sl-add-btn:hover { background: var(--accent-soft); }

.sl-list { display: flex; flex-direction: column; gap: 4px; margin-bottom: 12px; }
.sl-empty { font-size: 13px; color: var(--text-tertiary); margin: 0; }

.sl-row { display: flex; align-items: center; gap: 8px; padding: 6px 8px; border-radius: var(--radius-sm); background: var(--bg); border: 1px solid var(--border); }
.sl-name { flex: 1; font-size: 14px; color: var(--text); min-width: 0; overflow: hidden; text-overflow: ellipsis; white-space: nowrap; }
.sl-rule { font-family: var(--font-mono); font-size: 11px; color: var(--text-tertiary); white-space: nowrap; }
.sl-edit-btn, .sl-delete-btn { background: none; border: none; font-size: 14px; color: var(--text-tertiary); padding: 2px 4px; flex-shrink: 0; }
.sl-edit-btn:hover { color: var(--accent); }
.sl-delete-btn:hover { color: var(--urgent); }

.sl-form { display: flex; flex-direction: column; gap: 8px; padding: 12px; border: 1px solid var(--border); border-radius: var(--radius-sm); background: var(--bg); }
.sl-form-name, .sl-form-rule { width: 100%; font-size: 14px; font-family: var(--font-ui); border: 1px solid var(--border); border-radius: var(--radius-sm); padding: 7px 10px; background: var(--bg-elevated); color: var(--text); }
.sl-form-name:focus, .sl-form-rule:focus { outline: 2px solid var(--accent); outline-offset: -1px; }
.sl-form-actions { display: flex; gap: 8px; justify-content: flex-end; }
.sl-form-cancel { background: none; border: 1px solid var(--border); border-radius: var(--radius-sm); padding: 6px 12px; font-size: 13px; color: var(--text-secondary); }
.sl-form-cancel:hover { background: var(--border); }
.sl-form-save { background: var(--accent); border: none; border-radius: var(--radius-sm); padding: 6px 14px; font-size: 13px; font-weight: 600; color: white; }
.sl-form-save:hover { opacity: 0.9; }
.sl-form-save:disabled { opacity: 0.6; cursor: default; }

.settings-footer { padding-top: 8px; }
.settings-save-btn { width: 100%; background: var(--accent); border: none; border-radius: var(--radius); padding: 10px; font-size: 14px; font-weight: 600; color: white; }
.settings-save-btn:hover { opacity: 0.9; }
.settings-save-btn:disabled { opacity: 0.6; cursor: default; }

/* ===== Recurrence builder ===== */
.rb-wrapper { border: 1px solid var(--border); border-radius: var(--radius-sm); padding: 10px 12px; background: var(--bg); }
.rb-toggle-row { display: flex; align-items: center; justify-content: space-between; gap: 10px; }
.rb-toggle-label { display: flex; align-items: center; gap: 8px; font-size: 14px; color: var(--text-secondary); cursor: pointer; user-select: none; }
.rb-toggle-label input { accent-color: var(--accent); }
.rb-summary { font-family: var(--font-mono); font-size: 11px; color: var(--text-tertiary); }
.rb-body { margin-top: 12px; display: flex; flex-direction: column; gap: 10px; }
.rb-row { display: flex; align-items: center; gap: 8px; flex-wrap: wrap; }
.rb-label { font-size: 12px; color: var(--text-tertiary); width: 44px; flex-shrink: 0; }
.rb-interval { width: 52px; font-size: 14px; font-family: var(--font-mono); border: 1px solid var(--border); border-radius: var(--radius-sm); padding: 5px 6px; background: var(--bg-elevated); color: var(--text); text-align: center; }
.rb-frequency, .rb-monthly-type, .rb-relative-week, .rb-relative-day, .rb-end-type, .rb-end-date { font-size: 13px; font-family: var(--font-ui); border: 1px solid var(--border); border-radius: var(--radius-sm); padding: 5px 8px; background: var(--bg-elevated); color: var(--text); }
.rb-end-count { width: 60px; font-size: 14px; font-family: var(--font-mono); border: 1px solid var(--border); border-radius: var(--radius-sm); padding: 5px 6px; background: var(--bg-elevated); color: var(--text); text-align: center; }
.rb-end-count-label { font-size: 13px; color: var(--text-secondary); }
.rb-day-btns { display: flex; gap: 4px; }
.rb-day-btn { width: 30px; height: 30px; border-radius: 50%; border: 1px solid var(--border); background: var(--bg-elevated); color: var(--text-secondary); font-size: 12px; font-weight: 600; cursor: pointer; transition: background 0.12s ease, border-color 0.12s ease, color 0.12s ease; }
.rb-day-btn.active { background: var(--accent); border-color: var(--accent); color: white; }
.rb-day-btn:hover:not(.active) { border-color: var(--accent); color: var(--accent); }

/* ===== Responsive ===== */
@media (max-width: 720px) {
  .main { padding: 0 16px 16px; }
  .detail-panel { width: 100%; }

  /* On mobile, sidebar becomes a slide-in drawer over the content */
  .sidebar {
    position: fixed;
    top: 0;
    left: 0;
    height: 100%;
    z-index: 30;
    transform: translateX(-100%);
    transition: transform 0.22s ease, width 0.2s ease;
    width: var(--sidebar-width) !important; /* always full width when open, never collapsed */
    box-shadow: 2px 0 12px rgba(0,0,0,0.15);
  }
  .sidebar.mobile-open {
    transform: translateX(0);
  }
  /* Backdrop behind the open sidebar on mobile */
  .sidebar-backdrop {
    display: none;
    position: fixed;
    inset: 0;
    background: rgba(0,0,0,0.3);
    z-index: 29;
  }
  .sidebar-backdrop.open { display: block; }

  /* Always show all sidebar content on mobile (no collapsed state) */
  .sidebar.collapsed .brand,
  .sidebar.collapsed .nav-label,
  .sidebar.collapsed .nav-item-count,
  .sidebar.collapsed .settings-btn,
  .sidebar.collapsed .nav-item span:first-child { display: unset; }
  .sidebar.collapsed .nav-item { justify-content: space-between; padding: 7px 8px; }
  .sidebar.collapsed .sidebar-header { padding: 0 20px 20px; justify-content: space-between; }

  /* Hamburger button always visible in topbar on mobile */
  .mobile-menu-btn {
    display: flex;
    align-items: center;
    background: none;
    border: none;
    color: var(--text-secondary);
    padding: 4px;
    margin-right: 4px;
  }
}

@media (min-width: 721px) {
  .mobile-menu-btn { display: none; }
  .sidebar-backdrop { display: none !important; }
}

/* ===== Reduced motion ===== */
@media (prefers-reduced-motion: reduce) {
  * { animation-duration: 0.01ms !important; transition-duration: 0.01ms !important; }
}

/* ===== Focus visibility ===== */
:focus-visible { outline: 2px solid var(--accent); outline-offset: 2px; }