/**
 * Design system — inspired by [untitled] (untitled.stream)
 * Shared across hub and all tools.
 */
:root {
  --u-bg: #0a0a0a;
  --u-bg-subtle: #0f0f0f;
  --u-surface: #141414;
  --u-surface-raised: #1a1a1a;
  --u-surface-hover: #222222;
  --u-border: rgba(255, 255, 255, 0.08);
  --u-border-strong: rgba(255, 255, 255, 0.14);
  --u-text: #fafafa;
  --u-text-secondary: #a3a3a3;
  --u-text-muted: #737373;
  --u-text-faint: #525252;
  --u-accent: #fafafa;
  --u-accent-hover: #e5e5e5;
  --u-accent-muted: rgba(255, 255, 255, 0.12);
  --u-success: #4ade80;
  --u-success-bg: rgba(74, 222, 128, 0.1);
  --u-warning: #fbbf24;
  --u-warning-bg: rgba(251, 191, 36, 0.1);
  --u-error: #f87171;
  --u-error-bg: rgba(248, 113, 113, 0.1);
  --u-radius-sm: 6px;
  --u-radius: 10px;
  --u-radius-lg: 14px;
  --u-radius-xl: 18px;
  --u-shadow: 0 1px 2px rgba(0, 0, 0, 0.4);
  --u-shadow-lg: 0 8px 32px rgba(0, 0, 0, 0.5);
  --u-font: 'IBM Plex Sans', -apple-system, BlinkMacSystemFont, 'Segoe UI', system-ui, sans-serif;
  --u-transition: 0.15s ease;
}

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

html {
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

html {
  overflow-x: hidden;
  -webkit-text-size-adjust: 100%;
}

body.u-theme {
  font-family: var(--u-font);
  background: var(--u-bg);
  color: var(--u-text);
  line-height: 1.5;
  overflow-x: hidden;
  overflow-y: auto;
  -webkit-overflow-scrolling: touch;
}

/* Tailwind CDN bridge — map utility classes to tokens */
.u-theme.bg-u-bg { background-color: var(--u-bg) !important; }
.u-theme.bg-u-surface { background-color: var(--u-surface) !important; }
.u-theme.bg-u-surface-raised { background-color: var(--u-surface-raised) !important; }
.u-theme.text-u-text { color: var(--u-text) !important; }
.u-theme.text-u-secondary { color: var(--u-text-secondary) !important; }
.u-theme.text-u-muted { color: var(--u-text-muted) !important; }
.u-theme.border-u { border-color: var(--u-border) !important; }
.u-theme.border-u-strong { border-color: var(--u-border-strong) !important; }

/* Cards & panels */
.u-card {
  background: var(--u-surface);
  border: 1px solid var(--u-border);
  border-radius: var(--u-radius-lg);
  padding: 1.5rem;
}

.u-card-raised {
  background: var(--u-surface-raised);
  border: 1px solid var(--u-border);
  border-radius: var(--u-radius-lg);
}

/* Form controls */
.u-input,
.u-select,
.u-textarea {
  width: 100%;
  padding: 0.625rem 0.875rem;
  background: var(--u-surface-raised);
  border: 1px solid var(--u-border);
  border-radius: var(--u-radius);
  color: var(--u-text);
  font-size: 0.875rem;
  font-family: inherit;
  transition: border-color var(--u-transition), box-shadow var(--u-transition);
}

.u-input::placeholder,
.u-textarea::placeholder {
  color: var(--u-text-faint);
}

.u-input:focus,
.u-select:focus,
.u-textarea:focus {
  outline: none;
  border-color: var(--u-border-strong);
  box-shadow: 0 0 0 3px rgba(255, 255, 255, 0.06);
}

.u-label {
  display: block;
  font-size: 0.8125rem;
  font-weight: 500;
  color: var(--u-text-secondary);
  margin-bottom: 0.375rem;
}

/* Buttons */
.u-btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 0.5rem;
  padding: 0.5625rem 1rem;
  border-radius: var(--u-radius);
  font-size: 0.875rem;
  font-weight: 500;
  font-family: inherit;
  border: none;
  cursor: pointer;
  transition: background var(--u-transition), opacity var(--u-transition), border-color var(--u-transition);
  text-decoration: none;
}

.u-btn:disabled {
  opacity: 0.45;
  cursor: not-allowed;
}

.u-btn-primary {
  background: var(--u-accent);
  color: #0a0a0a;
}

.u-btn-primary:hover:not(:disabled) {
  background: var(--u-accent-hover);
}

.u-btn-ghost {
  background: transparent;
  color: var(--u-text-secondary);
  border: 1px solid var(--u-border);
}

.u-btn-ghost:hover:not(:disabled) {
  background: var(--u-surface-hover);
  color: var(--u-text);
  border-color: var(--u-border-strong);
}

.u-btn-sm {
  padding: 0.375rem 0.75rem;
  font-size: 0.8125rem;
}

/* Badges */
.u-badge {
  display: inline-flex;
  align-items: center;
  gap: 0.375rem;
  padding: 0.25rem 0.625rem;
  border-radius: 999px;
  font-size: 0.6875rem;
  font-weight: 500;
  letter-spacing: 0.02em;
  border: 1px solid var(--u-border);
  background: var(--u-surface-raised);
  color: var(--u-text-muted);
}

.u-badge-success {
  background: var(--u-success-bg);
  border-color: rgba(74, 222, 128, 0.2);
  color: var(--u-success);
}

.u-badge-error {
  background: var(--u-error-bg);
  border-color: rgba(248, 113, 113, 0.2);
  color: var(--u-error);
}

.u-badge-warning {
  background: var(--u-warning-bg);
  border-color: rgba(251, 191, 36, 0.2);
  color: var(--u-warning);
}

/* Section headers */
.u-page-header h1 {
  font-size: 1.375rem;
  font-weight: 600;
  letter-spacing: -0.025em;
  color: var(--u-text);
}

.u-page-header p {
  font-size: 0.875rem;
  color: var(--u-text-muted);
  margin-top: 0.25rem;
}

.u-section-label {
  font-size: 0.625rem;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.14em;
  color: var(--u-text-faint);
}

/* Dropzone */
.u-dropzone {
  border: 1px dashed var(--u-border-strong);
  border-radius: var(--u-radius-lg);
  padding: 2rem;
  text-align: center;
  cursor: pointer;
  transition: border-color var(--u-transition), background var(--u-transition);
}

.u-dropzone:hover {
  border-color: rgba(255, 255, 255, 0.22);
  background: rgba(255, 255, 255, 0.02);
}

/* Progress */
.u-progress {
  height: 3px;
  background: var(--u-surface-hover);
  border-radius: 999px;
  overflow: hidden;
}

.u-progress-bar {
  height: 100%;
  background: var(--u-text);
  border-radius: 999px;
  transition: width 0.35s ease;
}

/* Tables */
.u-table thead {
  color: var(--u-text-muted);
  font-size: 0.6875rem;
  text-transform: uppercase;
  letter-spacing: 0.06em;
}

.u-table tbody tr {
  border-bottom: 1px solid var(--u-border);
}

.u-table tbody tr:hover {
  background: rgba(255, 255, 255, 0.02);
}

/* Scrollbar */
.u-scroll::-webkit-scrollbar { width: 5px; height: 5px; }
.u-scroll::-webkit-scrollbar-thumb { background: #333; border-radius: 3px; }
.u-scroll::-webkit-scrollbar-track { background: transparent; }

/* Brand mark */
.u-brand {
  font-weight: 500;
  letter-spacing: -0.02em;
  color: var(--u-text);
}

.u-brand-brackets {
  color: var(--u-text-muted);
  font-weight: 400;
}

/* Stat cards */
.u-stat {
  background: var(--u-surface);
  border: 1px solid var(--u-border);
  border-radius: var(--u-radius-lg);
  padding: 1rem 1.25rem;
}

.u-stat-label {
  font-size: 0.6875rem;
  font-weight: 500;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  color: var(--u-text-muted);
}

.u-stat-value {
  font-size: 1.5rem;
  font-weight: 600;
  letter-spacing: -0.02em;
  color: var(--u-text);
  margin-top: 0.25rem;
}

/* Module tabs — shared pattern across tools */
.u-tabs {
  display: flex;
  gap: 0.25rem;
  padding: 0.25rem;
  border-radius: var(--u-radius);
  background: var(--u-surface);
  border: 1px solid var(--u-border);
  width: fit-content;
}

.u-tab {
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  padding: 0.5rem 1rem;
  border-radius: var(--u-radius-sm);
  font-size: 0.875rem;
  font-weight: 500;
  color: var(--u-text-muted);
  background: transparent;
  border: none;
  cursor: pointer;
  font-family: inherit;
  text-decoration: none;
  transition: color var(--u-transition), background var(--u-transition);
}

.u-tab:hover:not(.u-tab--active) {
  color: var(--u-text-secondary);
}

.u-tab--active {
  color: var(--u-text);
  background: var(--u-surface-raised);
}

.u-tab-panel[hidden] {
  display: none !important;
}

/* Form action bar */
.u-form-actions {
  margin-top: 0.25rem;
  padding-top: 1.25rem;
  border-top: 1px solid var(--u-border);
}

/* Page shell — tools embedded in hub iframe */
.u-shell {
  width: 100%;
  max-width: 100%;
  min-width: 0;
  margin-left: auto;
  margin-right: auto;
  padding: 1rem 0.75rem 2rem;
  box-sizing: border-box;
}

.u-shell--md { max-width: 48rem; }
.u-shell--lg { max-width: 72rem; }

@media (min-width: 640px) {
  .u-shell {
    padding: 1.25rem 1.25rem 2.5rem;
  }
}

@media (min-width: 768px) {
  .u-shell {
    padding: 1.5rem 1.5rem 3rem;
  }
}

/* Tool panel — MailAuto-style sections */
.u-panel {
  background: var(--u-surface);
  border: 1px solid var(--u-border);
  border-radius: var(--u-radius-lg);
  padding: 1rem;
  box-shadow: var(--u-shadow-lg);
}

@media (min-width: 640px) {
  .u-panel {
    padding: 1.5rem;
  }
}

/* Scrollable table wrapper */
.u-table-wrap {
  overflow-x: auto;
  -webkit-overflow-scrolling: touch;
  max-width: 100%;
}

.u-table-wrap > table {
  min-width: 36rem;
}

/* Responsive button rows */
.u-btn-row {
  display: flex;
  flex-direction: column;
  gap: 0.5rem;
}

@media (min-width: 640px) {
  .u-btn-row {
    flex-direction: row;
    flex-wrap: wrap;
  }
}

.u-btn-row > .u-btn,
.u-btn-row > button,
.u-btn-row > a.u-btn {
  width: 100%;
}

@media (min-width: 640px) {
  .u-btn-row > .u-btn,
  .u-btn-row > button,
  .u-btn-row > a.u-btn {
    width: auto;
  }
}

.u-attach-buttons {
  display: grid;
  grid-template-columns: 1fr;
  gap: 0.5rem;
}

@media (min-width: 400px) {
  .u-attach-buttons {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }
}

@media (min-width: 640px) {
  .u-attach-buttons {
    display: flex;
    flex-wrap: wrap;
  }

  .u-attach-buttons > button {
    width: auto;
  }
}

.u-attach-buttons > button {
  width: 100%;
  justify-content: center;
}

/* List item with actions */
.u-list-item {
  display: flex;
  flex-direction: column;
  align-items: stretch;
  gap: 0.75rem;
  padding: 0.75rem;
  border-radius: var(--u-radius);
  background: var(--u-surface-raised);
  border: 1px solid var(--u-border);
}

@media (min-width: 640px) {
  .u-list-item {
    flex-direction: row;
    align-items: center;
    justify-content: space-between;
    gap: 0.5rem;
    padding: 0.75rem;
  }
}

.u-list-item__actions {
  display: flex;
  flex-wrap: wrap;
  gap: 0.375rem;
  flex-shrink: 0;
}

@media (max-width: 639px) {
  .u-list-item__actions > button {
    flex: 1;
    min-width: 0;
  }
}

/* Modal footer */
.u-modal-footer {
  display: flex;
  flex-direction: column-reverse;
  gap: 0.5rem;
}

@media (min-width: 640px) {
  .u-modal-footer {
    flex-direction: row;
    justify-content: flex-end;
  }
}

@media (max-width: 639px) {
  .u-modal-footer > button {
    width: 100%;
  }
}

/* Master-detail — mobile shows list OR detail */
.u-master-detail {
  display: grid;
  gap: 1rem;
}

@media (min-width: 768px) {
  .u-master-detail {
    grid-template-columns: 260px 1fr;
  }

  .u-master-detail__back {
    display: none !important;
  }
}

@media (max-width: 767px) {
  .u-master-detail[data-view="detail"] .u-master-detail__nav {
    display: none;
  }

  .u-master-detail[data-view="list"] .u-master-detail__detail {
    display: none;
  }
}

.u-master-detail__back {
  display: inline-flex;
  align-items: center;
  gap: 0.375rem;
  padding: 0.375rem 0.625rem;
  margin-bottom: 0.25rem;
  border-radius: var(--u-radius-sm);
  border: 1px solid var(--u-border);
  background: transparent;
  color: var(--u-text-secondary);
  font-size: 0.8125rem;
  font-weight: 500;
  font-family: inherit;
  cursor: pointer;
  transition: background var(--u-transition), color var(--u-transition);
}

.u-master-detail__back:hover {
  background: var(--u-surface-hover);
  color: var(--u-text);
}

@media (max-width: 639px) {
  .u-card {
    padding: 1rem;
  }

  .u-panel {
    padding: 1rem;
  }

  .u-dropzone {
    padding: 1.25rem 0.875rem;
  }

  .u-page-header h1 {
    font-size: 1.125rem;
  }

  .u-page-header p {
    font-size: 0.8125rem;
  }
}

/* Code inline */
.u-theme code {
  font-size: 0.8125em;
  background: var(--u-surface-raised);
  border: 1px solid var(--u-border);
  padding: 0.125rem 0.375rem;
  border-radius: var(--u-radius-sm);
  color: var(--u-text-secondary);
  overflow-wrap: anywhere;
  word-break: break-word;
}

.u-theme details {
  overflow-wrap: anywhere;
}