/* Shared appearance layer. Preset colors, layout, card geometry and behavior remain owned
   by their existing modules. Light presets use softer shadows and darker accent ink. */
:root {
  --ui-middle-border-width: 2px;
  --ui-left-bottom-border-width: 2px;
  --ui-top-right-border-width: 1.5px;
  --ui-border-color: #4b5563;
  --ui-shadow-strength: 1.5;
  --ui-blue: #8ab8ff;
  --ui-teal: #5cd9c4;
  --ui-amber: #f2bf77;
  --ui-rose: #f39bae;
  --ui-accent: var(--primary);
  --ui-accent-ink: color-mix(in srgb, var(--primary) 78%, var(--text));
  --ui-button-fill: var(--primary);
  --ui-button-top: color-mix(in srgb, var(--ui-button-fill) 84%, white);
  --ui-button-ink: color-mix(in srgb, var(--background) 92%, black);
  --ui-ground: var(--background);
  --ui-panel: color-mix(in srgb, var(--surface) 85%, var(--surface-alt));
  --ui-panel-top: color-mix(in srgb, var(--surface) 62%, var(--surface-alt));
  --ui-raised: color-mix(in srgb, var(--surface-alt) 94%, var(--text));
  --ui-field: color-mix(in srgb, var(--background) 78%, var(--surface));
  --ui-field-line: var(--ui-border-color);
  --ui-rim: var(--ui-border-color);
  --ui-highlight: rgb(255 255 255 / .09);
  --ui-shadow-rgb: 0 0 0;
  --ui-shadow-base: .48;
  --ui-shadow-contact-base: .24;
  --ui-shadow-opacity: min(.9, calc(var(--ui-shadow-base) * var(--ui-shadow-strength)));
  --ui-shadow-close: min(.6, calc(var(--ui-shadow-contact-base) * var(--ui-shadow-strength)));
  --ui-line-inset: max(0px, calc(var(--ui-left-bottom-border-width) - 1px));
  --ui-surface-outline: inset 0 0 0 var(--ui-line-inset) var(--ui-rim);
  --shadow-sm: 0 3px 5px rgb(var(--ui-shadow-rgb) / var(--ui-shadow-close)), 0 10px 18px -9px rgb(var(--ui-shadow-rgb) / var(--ui-shadow-opacity));
  --shadow-md: 0 5px 8px -3px rgb(var(--ui-shadow-rgb) / var(--ui-shadow-close)), 0 22px 34px -13px rgb(var(--ui-shadow-rgb) / var(--ui-shadow-opacity));
  --shadow-lg: 0 10px 18px -6px rgb(var(--ui-shadow-rgb) / var(--ui-shadow-opacity)), 0 36px 74px -16px rgb(var(--ui-shadow-rgb) / var(--ui-shadow-opacity));
}
html:is([data-theme="classic"], [data-theme="paper"], [data-theme="lavender"], [data-theme="rose"], [data-theme="arctic"], [data-theme="cotton_candy"]) {
  --ui-blue: #245eb1;
  --ui-teal: #08786a;
  --ui-amber: #965409;
  --ui-rose: #b03661;
  --warning: #965409;
  --ui-button-fill: color-mix(in srgb, var(--primary) 82%, var(--text));
  --ui-button-top: color-mix(in srgb, var(--ui-button-fill) 96%, white);
  --ui-button-ink: #fff;
  --ui-ground: var(--background);
  --ui-panel: var(--surface);
  --ui-panel-top: color-mix(in srgb, var(--surface) 96%, white);
  --ui-raised: var(--surface);
  --ui-field: color-mix(in srgb, var(--surface) 80%, var(--background));
  --ui-highlight: rgb(255 255 255 / .95);
  --ui-shadow-rgb: 24 34 48;
  --ui-shadow-base: .24;
  --ui-shadow-contact-base: .11;
}
html[data-theme="cotton_candy"] { --ui-blue: #387AB1; --ui-teal: #357E9E; --ui-rose: #BC438A; }
.course-code-prefix input:placeholder-shown, .course-code-number input:placeholder-shown { border-style: dashed; }
.course-code-prefix input::placeholder, .course-code-number input::placeholder { color: var(--muted); font-style: italic; opacity: .6; font-weight: 400; }
.course-code-prefix input:not(:placeholder-shown), .course-code-number input:not(:placeholder-shown) { color: var(--text); font-weight: 650; }

/* Four opaque, nested edge paints: left/bottom, outer line, middle band, inner line.
   Each successive top/right boundary adds a width, so the enclosing lines always touch
   the band. Subtract the existing 1px physical border; no layout or hit area changes. */
.panel, .surface-panel, .metric-card, .modal, .home-launch-card, .create-choice,
.column-folder, .folder-child-card, .theme-choice, .button.primary, .button.secondary,
.deck-overview-hero, .plan-detail-hero {
  --ui-edge-scale: 1;
  --ui-edge-color: var(--ui-middle-border-color, color-mix(in srgb, var(--ui-accent) 78%, var(--ui-panel)));
  --ui-lb-inset: max(0px, calc(var(--ui-left-bottom-border-width) * var(--ui-edge-scale) - 1px));
  --ui-outline-size: max(1px, calc(var(--ui-top-right-border-width) * var(--ui-edge-scale)));
  --ui-band-size: calc(var(--ui-middle-border-width) * var(--ui-edge-scale));
  --ui-outer-inset: calc(var(--ui-outline-size) - 1px);
  --ui-middle-inset: calc(var(--ui-outline-size) + var(--ui-band-size) - 1px);
  --ui-inner-inset: calc(2 * var(--ui-outline-size) + var(--ui-band-size) - 1px);
  --ui-bevel: inset var(--ui-lb-inset) calc(-1 * var(--ui-lb-inset)) 0 0 var(--ui-border-color), inset calc(-1 * var(--ui-outer-inset)) var(--ui-outer-inset) 0 0 var(--ui-border-color), inset calc(-1 * var(--ui-middle-inset)) var(--ui-middle-inset) 0 0 var(--ui-edge-color), inset calc(-1 * var(--ui-inner-inset)) var(--ui-inner-inset) 0 0 var(--ui-border-color);
}
.button.primary, .button.secondary, .theme-choice { --ui-edge-scale: .5; }

/* The page sits behind distinct navigation, content panels and raised controls. */
.app-layout, .landing-page {
  background: radial-gradient(ellipse at 48% 0, color-mix(in srgb, var(--primary) 7%, transparent), transparent 58%), var(--ui-ground);
}
.app-sidebar {
  background: linear-gradient(165deg, var(--ui-panel-top), var(--surface) 52%, color-mix(in srgb, var(--surface) 82%, var(--background)));
  border-right-color: var(--ui-rim);
  box-shadow: 8px 0 24px -18px rgb(var(--ui-shadow-rgb) / var(--ui-shadow-opacity));
}
.mobile-app-header, .settings-section-nav {
  background: var(--ui-panel);
  border-color: var(--ui-rim);
  box-shadow: var(--ui-surface-outline), var(--shadow-sm);
}
.sidebar-link.active {
  color: var(--text);
  background: linear-gradient(115deg, color-mix(in srgb, var(--primary) 23%, var(--ui-panel)), color-mix(in srgb, var(--primary) 9%, var(--ui-panel)));
  border-color: var(--ui-border-color);
  box-shadow: var(--ui-surface-outline), var(--shadow-sm);
}
.app-ad-rail { border-left-color: var(--border); background: color-mix(in srgb, var(--background) 62%, var(--surface)); }
.panel, .surface-panel, .metric-card {
  background-color: var(--ui-panel);
  border-color: var(--ui-rim);
  box-shadow: var(--ui-bevel), var(--shadow-md);
}
.dashboard-panel, .settings-section, .active-session-card {
  background-image: linear-gradient(155deg, var(--ui-panel-top), var(--ui-panel) 60%);
}
.modal {
  background: var(--ui-panel);
  border-color: var(--ui-rim);
  box-shadow: var(--ui-bevel), var(--shadow-lg);
}
.modal-header {
  background: linear-gradient(120deg, var(--ui-panel-top), var(--ui-panel));
  border-bottom-color: var(--ui-rim);
  box-shadow: 0 3px 8px -6px rgb(var(--ui-shadow-rgb) / var(--ui-shadow-opacity));
}
.deck-detail-footer, .settings-save-bar, .workspace-selection-bar {
  background: var(--ui-panel-top);
  border-color: var(--ui-rim);
  box-shadow: var(--shadow-md);
}
.deck-overview-hero, .plan-detail-hero {
  border-color: var(--ui-rim);
  background: linear-gradient(125deg, color-mix(in srgb, var(--ui-blue) 10%, var(--ui-raised)), var(--ui-panel));
  box-shadow: var(--ui-bevel), var(--shadow-sm);
}
.deck-overview-thumbnail .deck-thumbnail, .hero-product-frame { box-shadow: var(--shadow-lg); }

/* Recessed form fields contrast with their containing panels. No sizing or hit areas change. */
:where(.app-layout, .modal, .landing-page) :is(select, textarea, input:not([type="checkbox"], [type="radio"], [type="range"], [type="color"], [type="file"], [type="hidden"], [type="button"], [type="submit"])):not(.search-field input) {
  color: var(--text);
  background-color: var(--ui-field);
  border-color: var(--ui-field-line);
  box-shadow: inset 0 0 0 var(--ui-line-inset) var(--ui-field-line), inset 0 2px 4px rgb(var(--ui-shadow-rgb) / .14), 0 1px 0 var(--ui-highlight);
}
.search-field {
  background: var(--ui-field);
  border-color: var(--ui-field-line);
  box-shadow: inset 0 0 0 var(--ui-line-inset) var(--ui-field-line), inset 0 2px 4px rgb(var(--ui-shadow-rgb) / .14), 0 1px 0 var(--ui-highlight);
}
.search-field input { color: var(--text); background: transparent; box-shadow: none; }
.input-suffix > span { background: var(--surface-alt); border-color: var(--ui-field-line); color: var(--text); }
:where(.app-layout, .modal, .landing-page) :is(select, textarea, input:not([type="checkbox"], [type="radio"], [type="range"], [type="color"], [type="file"], [type="hidden"], [type="button"], [type="submit"])):not(.search-field input):focus, .search-field:focus-within {
  border-color: var(--primary);
  box-shadow: 0 0 0 3px color-mix(in srgb, var(--primary) 24%, transparent), inset 0 1px 3px rgb(var(--ui-shadow-rgb) / .1);
}
.search-field input:focus { box-shadow: none; }
input::placeholder, textarea::placeholder { color: var(--muted); opacity: 1; }
.button.primary {
  color: var(--ui-button-ink);
  background: linear-gradient(180deg, var(--ui-button-top), var(--ui-button-fill));
  border-color: var(--ui-border-color);
  box-shadow: var(--ui-bevel), 0 3px 0 -1px color-mix(in srgb, var(--ui-button-fill) 50%, black), 0 10px 18px -8px rgb(var(--ui-shadow-rgb) / var(--ui-shadow-opacity));
}
.button.primary:hover:not(:disabled) { background: linear-gradient(180deg, var(--ui-button-top), var(--ui-button-fill)); box-shadow: var(--ui-bevel), 0 3px 0 -1px color-mix(in srgb, var(--ui-button-fill) 50%, black), 0 14px 22px -8px rgb(var(--ui-shadow-rgb) / var(--ui-shadow-opacity)); }
.button.secondary {
  background: linear-gradient(180deg, var(--ui-raised), var(--ui-panel));
  border-color: var(--ui-rim);
  box-shadow: var(--ui-bevel), var(--shadow-sm);
}
.button.primary:active:not(:disabled), .button.secondary:active:not(:disabled) {
  box-shadow: inset 0 2px 4px rgb(var(--ui-shadow-rgb) / .25), 0 1px 0 var(--ui-highlight);
}
.text-button, .text-link, .eyebrow, .workspace-item-action, .workspace-file-arrow { color: var(--ui-accent-ink); }
.workspace-tabs > .active, .segmented-control button.active {
  background: color-mix(in srgb, var(--primary) 12%, var(--ui-panel));
  color: var(--ui-accent-ink);
  box-shadow: inset 0 1px 0 var(--ui-highlight);
}
.theme-choice {
  background: var(--ui-panel);
  border-color: var(--ui-rim);
  box-shadow: var(--ui-bevel), var(--shadow-sm);
}
.theme-choice:has(input:checked) {
  border-color: var(--ui-border-color);
  background: color-mix(in srgb, var(--primary) 10%, var(--ui-panel));
  box-shadow: var(--ui-bevel), var(--shadow-md);
}
.theme-preview { box-shadow: inset 0 1px 0 rgb(255 255 255 / .18), 0 3px 6px rgb(var(--ui-shadow-rgb) / var(--ui-shadow-close)); }

/* Complementary accents identify tasks without replacing the selected preset. */
.home-launch-card[data-action="study"], .home-launch-card[data-action="library"], .study-launchpad a[href="#/app/library"], .create-choice[data-create="deck"] { --ui-accent: var(--ui-blue); }
.home-launch-card[data-action="notes"], .study-launchpad a[href="#/app/groups"], .create-choice[data-create="notes"], .create-choice[data-create="collection"] { --ui-accent: var(--ui-teal); }
.home-launch-card[data-action="lecture"], .create-choice[data-create="lecture"] { --ui-accent: var(--ui-rose); }
.study-launchpad a[href="#/app/today"], .create-choice[data-create="test"], .create-choice[data-create="plan"], .create-choice[data-create="import"] { --ui-accent: var(--ui-amber); }
.home-launch-card, .create-choice {
  color: var(--text);
  background: linear-gradient(135deg, color-mix(in srgb, var(--ui-accent) 12%, var(--ui-raised)), var(--ui-panel) 74%);
  border-color: var(--ui-border-color);
  box-shadow: var(--ui-bevel), var(--shadow-md);
}
.home-launch-card > svg:first-child, .create-choice > svg {
  color: var(--ui-accent);
  filter: drop-shadow(0 3px 2px rgb(var(--ui-shadow-rgb) / var(--ui-shadow-close)));
}
.home-launch-card > svg:last-child { color: var(--ui-accent); }
.home-launch-card > span, .create-choice small { color: var(--muted); }
.dashboard-day-line:nth-of-type(1) > svg { color: var(--ui-blue); }
.dashboard-day-line:nth-of-type(2) > svg { color: var(--ui-amber); }
.dashboard-day-line:nth-of-type(3) > svg { color: var(--ui-teal); }
.workspace-tabs [data-tab="notes"].active { color: var(--ui-teal); border-bottom-color: var(--ui-teal); }
.workspace-tabs [data-tab="tests"].active { color: var(--ui-amber); border-bottom-color: var(--ui-amber); }
.dashboard-two-column > .dashboard-panel:nth-child(even) { --ui-accent: var(--ui-teal); }

/* Library wells recede; folder tiles sit above them. Ghost topics remain dashed and hollow. */
.library-browser-column:nth-child(4n + 1) { --ui-accent: var(--primary); }
.library-browser-column:nth-child(4n + 2) { --ui-accent: var(--ui-blue); }
.library-browser-column:nth-child(4n + 3) { --ui-accent: var(--ui-amber); }
.library-browser-column:nth-child(4n + 4) { --ui-accent: var(--ui-teal); }
.library-browser-column {
  background: linear-gradient(180deg, color-mix(in srgb, var(--ui-accent) 7%, var(--ui-panel)), color-mix(in srgb, var(--background) 75%, var(--surface)) 105px);
  border-color: var(--ui-rim);
  box-shadow: inset 0 1px 0 var(--ui-highlight), 0 6px 12px -9px rgb(var(--ui-shadow-rgb) / var(--ui-shadow-opacity));
}
.library-column-heading > svg { color: var(--ui-accent); }
.column-folder, .folder-child-card {
  background: linear-gradient(155deg, var(--ui-raised), var(--ui-panel));
  border-color: var(--ui-rim);
  box-shadow: var(--ui-bevel), var(--shadow-sm);
}
.column-folder.is-selected {
  background: linear-gradient(125deg, color-mix(in srgb, var(--ui-accent) 16%, var(--ui-raised)), var(--ui-panel));
  border-color: var(--ui-border-color);
  box-shadow: var(--ui-bevel), var(--shadow-sm);
}
.column-folder-select > svg:first-child { color: var(--ui-accent); }
.column-visit-page { color: color-mix(in srgb, var(--ui-accent) 80%, var(--text)); }
.column-folder.is-ghost, .folder-child-card.is-ghost { box-shadow: none; border-color: var(--ui-field-line); }
.workspace-material-item { background: color-mix(in srgb, var(--surface-alt) 30%, var(--ui-panel)); border-color: var(--ui-rim); }
.workspace-material-item:nth-child(even) { background: color-mix(in srgb, var(--surface-alt) 12%, var(--ui-panel)); }
.workspace-material-item > a > svg { color: var(--ui-blue); }
.workspace-material-item > a[href*="/app/notebook/"] > svg { color: var(--ui-teal); }
.topic-warning { color: var(--warning); }
.upcoming-test-card { --ui-accent: var(--ui-amber); }
.personal-plan-card { --ui-accent: var(--ui-teal); }

@media (hover: hover) {
  .home-launch-card:hover, .create-choice:not(:disabled):hover {
    border-color: var(--ui-border-color);
    background: linear-gradient(135deg, color-mix(in srgb, var(--ui-accent) 20%, var(--ui-raised)), var(--ui-panel) 85%);
    box-shadow: var(--ui-bevel), var(--shadow-lg);
  }
  .column-folder:not(.is-ghost):hover { border-color: var(--ui-border-color); box-shadow: var(--ui-bevel), var(--shadow-md); }
  .workspace-material-item:hover { background: color-mix(in srgb, var(--primary) 9%, var(--ui-panel)); }
  .button.secondary:hover:not(:disabled) { background: var(--ui-raised); border-color: var(--ui-field-line); box-shadow: var(--ui-bevel), var(--shadow-md); }
}

/* Appearance controls and their live preview are confined to Settings. */
.appearance-depth-settings { margin: 22px 0; padding-top: 20px; border-top: 1px solid var(--ui-rim); }
.appearance-border-preview { display: grid; gap: 8px; padding: 24px; margin-bottom: 22px; min-height: 130px; }
.appearance-border-preview strong { font-size: 20px; }
.appearance-border-preview small { color: var(--muted); }
.appearance-color-control { display: grid; grid-template-columns: 48px minmax(0, 1fr); gap: 10px; }
.appearance-color-control input { width: 100%; min-width: 0; }
.appearance-color-control input[type="color"] { padding: 4px; cursor: pointer; }
.appearance-color-auto { display: flex; align-items: center; gap: 8px; font-size: 12px; color: var(--muted); }
.appearance-adjuster { display: grid; grid-template-columns: minmax(80px, 1fr) 112px; align-items: center; gap: 14px; }
.appearance-adjuster input[type="range"] { width: 100%; min-width: 0; padding: 0; accent-color: var(--primary); border: 0; box-shadow: none; }
.appearance-adjuster .input-suffix { min-width: 0; }
.appearance-adjuster .input-suffix > span { min-width: 32px; }
.appearance-adjuster input[type="number"] { width: 100%; min-width: 0; padding-inline: 8px; }
.appearance-depth-footer { display: flex; flex-wrap: wrap; align-items: center; gap: 12px; margin-top: 16px; }
.appearance-save-status { color: var(--muted); }
@media (forced-colors: active) {
  .panel, .modal, .home-launch-card, .create-choice, .column-folder, .library-browser-column, .button { box-shadow: none; filter: none; }
  .column-folder.is-selected, .theme-choice:has(input:checked), .sidebar-link.active { border-color: Highlight; outline: 1px solid Highlight; }
}
@media print {
  .panel, .surface-panel, .metric-card, .column-folder, .library-browser-column, .button, .home-launch-card, .create-choice { box-shadow: none; filter: none; }
  .app-layout, .landing-page { background: none; }
}
/* Online routes mount their loading state before waiting for server responses. */
.deferred-online-view { min-height: 60vh; }
.online-loading-skeleton { display: grid; grid-template-columns: repeat(auto-fit, minmax(220px, 1fr)); gap: 20px; margin-top: 28px; }
.online-loading-skeleton > div { min-height: 180px; border-radius: 18px; background: var(--surface-alt); border: 1px solid var(--border); }
.card-copy-choices { display: grid; gap: 10px; max-height: 50vh; overflow: auto; padding: 4px; }
.card-copy-choices button { justify-content: flex-start; white-space: normal; text-align: left; }
.course-gradebook { min-width: 0; }
.grade-table-scroll { width: 100%; overflow-x: auto; margin: 24px 0; }
.grade-table { width: 100%; border-collapse: collapse; text-align: left; }
.grade-table caption { text-align: left; font-weight: 700; font-size: 1.15rem; margin-bottom: 14px; }
.grade-table th, .grade-table td { padding: 9px; border-bottom: 1px solid var(--border); vertical-align: middle; }
.grade-table th { font-size: .8rem; color: var(--muted); }
.grade-table input, .grade-table select { width: 120px; min-width: 95px; }
.grade-table input[data-field="name"] { width: 190px; }
.grade-table input[type="date"] { width: 150px; }
.grade-table input:disabled { opacity: .45; }
.grade-table input:read-only { border-style: dashed; }
.grade-category { display: flex; gap: 12px; align-items: end; margin-bottom: 12px; }
.grade-category .field { flex: 1; min-width: 0; }
.grade-actions { display: flex; flex-wrap: wrap; align-items: center; gap: 12px; }
.grade-results { display: grid; grid-template-columns: repeat(auto-fit,minmax(180px,1fr)); gap: 18px; margin: 26px 0 16px; }
.grade-results article { display: grid; gap: 8px; padding: 18px; border: 1px solid var(--border); border-radius: 14px; background: var(--surface-alt); }
.grade-results strong { font-size: 1.5rem; }
.grade-results small, .grade-results span { color: var(--muted); }
.grade-results .inline-notice { grid-column: 1/-1; }
@media (max-width: 600px) { .grade-category { flex-wrap: wrap; } .course-gradebook .dashboard-panel-head { flex-wrap: wrap; } }