:root {
  color-scheme: light;
  font-family: Arial, Helvetica, sans-serif;
  color: #171717;
  background: #f4f5f6;
  font-size: 16px;
}
* { box-sizing: border-box; }
body { margin: 0; min-width: 320px; }
button, input, select, textarea { font: inherit; }
button { min-height: 40px; padding: 8px 14px; border: 1px solid #17697b; border-radius: 5px; background: #17697b; color: #fff; cursor: pointer; }
button.secondary { background: #fff; color: #174955; border-color: #9caeb3; }
button.danger { background: #a52f2f; border-color: #a52f2f; }
button.link-danger { border: 0; background: transparent; color: #a52f2f; }
input { width: 100%; min-height: 40px; border: 1px solid #aeb6ba; border-radius: 4px; padding: 8px 10px; background: #fff; }
textarea { width: 100%; border: 1px solid #aeb6ba; border-radius: 4px; padding: 8px 10px; background: #fff; resize: vertical; }
select { width: 100%; min-height: 40px; border: 1px solid #aeb6ba; border-radius: 4px; padding: 8px 10px; background: #fff; }
label { display: grid; gap: 5px; font-weight: 700; }
h1, h2, h3 { margin-top: 0; letter-spacing: 0; }
h1 { font-size: 24px; }
h2 { font-size: 19px; }
h3 { font-size: 17px; }
.app-header { height: 58px; padding: 0 18px; display: flex; align-items: center; justify-content: space-between; background: #fff; border-bottom: 1px solid #cfd5d8; }
.app-header > div { display: flex; align-items: center; gap: 12px; }
.app-brand img { width: 42px; height: 42px; object-fit: contain; }
.app-header a { color: #17697b; }
.account-nav { display: flex; align-items: center; gap: 16px; }
.mode { padding: 4px 8px; border-radius: 4px; font-size: 13px; font-weight: 700; }
.mode.preview { background: #fff0bd; color: #684e00; }
.mode.live { background: #d7f0df; color: #15572b; }
.app-layout { min-height: calc(100vh - 107px); display: grid; grid-template-columns: 250px minmax(0, 1fr); }
.domain-nav { background: #243238; color: #fff; padding: 18px 12px; }
.domain-nav h2 { padding: 0 8px; }
.domain-nav nav { display: grid; gap: 3px; margin-bottom: 14px; }
.domain-group { margin-bottom: 12px; }
.domain-group h3 { margin: 0; padding: 8px 9px 5px; color: #fff; font-size: 16px; }
.domain-nav nav a { color: #fff; text-decoration: none; display: grid; gap: 3px; padding: 9px 9px 9px 18px; border-left: 3px solid transparent; }
.domain-nav nav a.active { background: #34474f; border-left-color: #50c0d4; }
.domain-nav nav span { font-size: 13px; color: #c6d0d4; overflow-wrap: anywhere; }
.domain-nav form button { width: 100%; }
.customer-admin { margin-top: 14px; }
.customer-admin summary { cursor: pointer; padding: 8px; }
.customer-admin form { display: grid; gap: 8px; padding-top: 8px; }
.customer-admin label { color: #fff; font-size: 12px; }
.customer-admin label input { margin-top: 3px; }
.customer-summary { display: grid; gap: 2px; padding: 8px; border-bottom: 1px solid #405158; font-size: 12px; overflow-wrap: anywhere; }
.customer-summary span { color: #c6d0d4; }
.customer-summary form { display: block; padding: 4px 0 0; }
.customer-summary .customer-remove { width: auto; min-height: 30px; padding: 4px 8px; border-color: #bd5555; background: #8f2d2d; font-size: 12px; }
.mailbox-picker { display: grid; grid-template-columns: minmax(260px, 520px) auto; align-items: end; gap: 10px; }
.mailbox-options { display: grid; gap: 8px; max-width: 760px; }
.mailbox-option { display: grid; grid-template-columns: minmax(220px, 1fr) auto; align-items: center; gap: 12px; padding: 10px 12px; border: 1px solid #cfd5d8; border-radius: 4px; background: #fff; }
.mailbox-option span { color: #287044; font-weight: 700; }
.workspace { min-width: 0; padding: 20px; }
.workspace-heading { display: flex; justify-content: space-between; align-items: center; gap: 16px; margin-bottom: 16px; }
.workspace-heading h1 { margin-bottom: 3px; }
.workspace-heading p { margin: 0; color: #506269; }
.identity-grid { display: grid; grid-template-columns: repeat(5, minmax(135px, 1fr)); gap: 12px; margin-bottom: 18px; }
.tabs { display: flex; flex-wrap: wrap; border-bottom: 1px solid #aeb6ba; gap: 2px; }
.tabs .tab { color: #263b42; border: 1px solid transparent; border-bottom: 0; background: transparent; border-radius: 4px 4px 0 0; }
.tabs .tab.active { background: #fff; border-color: #aeb6ba; }
.tab-panel { display: none; min-height: 360px; padding: 18px 0; }
.tab-panel.active { display: block; }
.panel-heading { display: flex; align-items: center; justify-content: space-between; gap: 12px; margin-bottom: 12px; }
.panel-heading h2 { margin: 0; }
.repeat-list { display: grid; gap: 8px; margin-bottom: 10px; }
.new-folder-rule { display: grid; grid-template-columns: minmax(220px, 1fr) minmax(160px, .55fr) auto; gap: 10px; align-items: end; margin-bottom: 12px; padding: 12px; border: 1px solid #cfd5d8; border-radius: 5px; background: #fff; }
.rule-group { border: 1px solid #cfd5d8; border-radius: 5px; background: #fff; }
.rule-group summary { display: flex; justify-content: space-between; align-items: center; gap: 12px; padding: 11px 13px; cursor: pointer; list-style: none; }
.rule-group summary::-webkit-details-marker { display: none; }
.rule-summary-title { display: inline-flex; align-items: center; gap: 8px; min-width: 0; }
.collapse-arrow { width: 18px; color: #17697b; font-size: 16px; line-height: 1; }
.collapse-arrow::before { content: "▼"; }
.rule-group[open] .collapse-arrow::before { content: "▲"; }
.rule-group summary .rule-count { color: #506269; font-size: 13px; white-space: nowrap; }
.rule-group .rule-row { padding: 0 12px 12px; }
.rule-group-actions { display: flex; flex-wrap: wrap; gap: 8px; padding: 0 12px 12px; }
.rule-group-actions button { min-height: 34px; padding: 6px 10px; font-size: 14px; }
.save-folder-group { background: #17697b; border-color: #17697b; color: #fff; }
.rule-row { display: grid; grid-template-columns: minmax(240px, 1fr) 28px minmax(150px, .7fr) 42px; gap: 8px; align-items: start; }
.rule-row span { text-align: center; }
.panel-help { margin: -2px 0 12px; color: #506269; font-size: 14px; }
.combined-rules { max-width: 900px; min-height: 220px; line-height: 1.45; }
.simple-row { display: grid; grid-template-columns: minmax(220px, 620px) 42px; gap: 8px; }
.remove { width: 42px; padding: 0; background: #fff; color: #8b2424; border-color: #b9a3a3; font-size: 22px; }
.action-bar { display: flex; flex-wrap: wrap; gap: 8px; padding: 12px 0; background: #f4f5f6; border-top: 1px solid #cfd5d8; }
.top-actions { margin-bottom: 10px; border-top: 0; border-bottom: 1px solid #cfd5d8; }
.transfer-row { display: flex; align-items: end; flex-wrap: wrap; gap: 18px; margin-top: 20px; padding-top: 18px; border-top: 1px solid #cfd5d8; }
.transfer-row form { display: flex; align-items: end; gap: 8px; }
.export-control { display: grid; gap: 5px; }
.export-control span { font-weight: 700; }
.notice { margin-bottom: 14px; padding: 11px 13px; border-left: 4px solid; background: #fff; }
.notice.success { border-color: #268347; }
.notice.error { border-color: #b63131; }
.filter-preview { display: grid; gap: 8px; }
.filter-preview > div { display: grid; grid-template-columns: 260px minmax(220px, .8fr) minmax(300px, 1.4fr); gap: 12px; padding: 9px 0; border-bottom: 1px solid #d8dddf; }
.filter-preview span, .filter-preview code { overflow-wrap: anywhere; }
pre { overflow: auto; padding: 12px; background: #fff; border: 1px solid #cfd5d8; }
.setup-shell, .login-shell { width: min(680px, calc(100% - 32px)); margin: 60px auto; }
.setup-form, .login-form { background: #fff; border: 1px solid #cfd5d8; padding: 20px; }
.form-grid { display: grid; grid-template-columns: 1fr 1fr; gap: 14px; }
.form-grid .wide { grid-column: 1 / -1; }
.login-form { display: grid; gap: 14px; max-width: 420px; }
.empty-state { padding: 30px 0; }
.advanced-actions { margin-top: 22px; border-top: 1px solid #cfd5d8; padding-top: 14px; }
.advanced-actions summary { cursor: pointer; font-weight: 700; color: #40555d; }
.advanced-actions[open] { padding-bottom: 20px; }
.advanced-actions h2 { margin: 18px 0 6px; }
.advanced-actions form { display: grid; grid-template-columns: minmax(240px, 520px) auto; align-items: end; gap: 10px; }
.site-footer { min-height: 49px; display: flex; align-items: center; justify-content: space-between; flex-wrap: wrap; gap: 10px 18px; padding: 12px 18px; border-top: 1px solid #cfd5d8; background: #fff; color: #506269; font-size: 13px; }
.site-footer nav { display: flex; flex-wrap: wrap; gap: 14px; }
.site-footer a { color: #17697b; }
@media (max-width: 960px) {
  .app-layout { grid-template-columns: 1fr; }
  .domain-nav { padding: 12px; }
  .domain-nav nav { grid-template-columns: repeat(auto-fit, minmax(180px, 1fr)); }
  .identity-grid { grid-template-columns: repeat(2, minmax(0, 1fr)); }
  .filter-preview > div { grid-template-columns: 1fr; }
}
@media (max-width: 600px) {
  .app-header { height: auto; min-height: 58px; gap: 10px; padding: 8px 12px; }
  .app-brand { flex-wrap: wrap; }
  .app-brand img { width: 36px; height: 36px; }
  .workspace { padding: 12px; }
  .workspace-heading { align-items: stretch; flex-direction: column; }
  .workspace-heading form button { width: 100%; }
  .identity-grid, .form-grid { grid-template-columns: 1fr; }
  .form-grid .wide { grid-column: auto; }
  .new-folder-rule { grid-template-columns: 1fr; }
  .rule-row { grid-template-columns: 1fr 42px; }
  .rule-row span { display: none; }
  .rule-row [name="rule_folder[]"] { grid-column: 1; }
  .rule-row .remove { grid-column: 2; grid-row: 1 / 3; height: 100%; }
  .transfer-row form { width: 100%; align-items: stretch; flex-direction: column; }
  .export-control { width: 100%; }
  .advanced-actions form { grid-template-columns: 1fr; }
  .site-footer { align-items: flex-start; flex-direction: column; }
}

/* Optional 0.3.27 learning tab; existing mail-filter styles are unchanged. */
.learning-stats { display: flex; gap: 12px; flex-wrap: wrap; margin: 14px 0; }
.learning-stats > div { display: grid; gap: 4px; min-width: 145px; padding: 12px; background: #fff; border: 1px solid #cfd5d8; border-radius: 4px; }
.learning-stats strong { font-size: 24px; }
.learning-stats span { color: #506269; font-size: 13px; }
.learning-form { display: grid; grid-template-columns: repeat(2, minmax(0, 350px)); gap: 12px; margin: 18px 0; }
.learning-wide { grid-column: 1 / -1; }
.learning-checkbox { display: flex; align-items: center; gap: 9px; font-weight: 400; }
.learning-checkbox input { width: 19px; min-height: 19px; }
.learning-form > button { justify-self: start; }
.learning-tools { display: flex; align-items: end; gap: 15px; flex-wrap: wrap; margin: 16px 0; }
.learning-tools form { display: flex; align-items: end; gap: 8px; flex-wrap: wrap; }
.learning-tools label { min-width: 250px; }
.learning-folders { max-width: 730px; display: grid; gap: 5px; }
.learning-folders > div { display: flex; justify-content: space-between; gap: 10px; background: #fff; padding: 8px; }
@media (max-width: 600px) { .learning-form { grid-template-columns: 1fr; } .learning-tools form { width: 100%; } }
.learning-test { display: grid; max-width: 740px; gap: 10px; margin: 10px 0 14px; }
.learning-test > button { justify-self: start; }