@import url("https://fonts.googleapis.com/css2?family=IBM+Plex+Sans:ital,wght@0,300;0,400;0,600;1,300;1,400;1,600&display=swap");

:root {
  color-scheme: light;
  font-family: "IBM Plex Sans", sans-serif;
  font-synthesis: none;
  --page: #ffffff;
  --text: #212529;
  --brand: #33312e;
  --muted: #767676;
  --label: #808080;
  --line: #d7d7d7;
  --control: #ffffff;
  --control-text: #495057;
  --control-border: rgba(51, 49, 46, 0.2);
  --selected: #33312e;
  --selected-text: #ffffff;
  --menu-hover: #d9d9d9;
  --select-icon: #a9a9a9;
  --control-hover: #777777;
  --focus: rgba(13, 110, 253, 0.24);
}

:root[data-theme="dark"] {
  color-scheme: dark;
  --page: #171717;
  --text: #f1f1f1;
  --brand: #ffffff;
  --muted: #b8b8b8;
  --label: #c8bdb9;
  --line: #444444;
  --control: #222222;
  --control-text: #f1f1f1;
  --control-border: #5a5a5a;
  --selected: #f1f1f1;
  --selected-text: #171717;
  --menu-hover: #383838;
  --select-icon: #b8b8b8;
  --control-hover: #a0a0a0;
  --focus: rgba(255, 255, 255, 0.28);
}

* {
  box-sizing: border-box;
}

body {
  min-width: 320px;
  min-height: 100vh;
  margin: 0;
  font-size: 16px;
  font-weight: 400;
  line-height: 1.5;
  color: var(--text);
  background: var(--page);
  transition: color 160ms ease, background-color 160ms ease;
}

button,
select,
input {
  font: inherit;
}

button {
  color: inherit;
}

.site-header {
  min-height: 72px;
  margin: 0 15px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  border-bottom: 1px solid var(--line);
}

.brand {
  color: var(--brand);
  font-size: 42px;
  font-weight: 600;
  line-height: 1;
  letter-spacing: 0;
  text-decoration: none;
}

.theme-switcher {
  display: flex;
  align-items: center;
  gap: 14px;
  padding-right: 8px;
}

.theme-swatch {
  width: 28px;
  height: 28px;
  padding: 0;
  border: 3px solid var(--brand);
  border-radius: 50%;
  cursor: pointer;
  transition: transform 140ms ease, box-shadow 140ms ease;
}

.theme-swatch-light { background: #ffffff; }
.theme-swatch-dark { background: #202020; }
.theme-swatch:hover { transform: scale(1.06); }
.theme-swatch.is-active { box-shadow: inset 0 0 0 3px var(--page); }

main {
  min-height: calc(100vh - 72px);
  margin: 0 15px;
}

.filters {
  padding: 9px 0 17px;
  border-bottom: 1px solid var(--line);
}

.filter-grid {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  grid-template-rows: repeat(2, auto);
  column-gap: 0;
  row-gap: 8px;
}

.advanced-filters {
  display: contents;
}

.filter-field {
  min-width: 0;
}

.qualification-field {
  grid-column: 1;
  grid-row: 1;
}

.subject-field { grid-column: 1; grid-row: 2; }
.series-field { grid-column: 2; grid-row: 1; }
.paper-field { grid-column: 2; grid-row: 2; }
.topic-field { grid-column: 3; grid-row: 1; }
.subtopic-field { grid-column: 3; grid-row: 2; }

.series-field,
.paper-field,
.topic-field,
.subtopic-field {
  margin-left: 16px;
}

.filter-field > span {
  display: block;
  margin: 0 0 6px 5px;
  color: var(--label);
  font-size: 14px;
  font-weight: 300;
  line-height: 21px;
}

select {
  appearance: none;
  width: 100%;
  height: 38px;
  padding: 0 48px 0 11px;
  border: 1px solid var(--control-border);
  border-radius: 4px;
  color: var(--control-text);
  background-color: var(--control);
  background-image:
    linear-gradient(var(--control-border), var(--control-border)),
    linear-gradient(45deg, transparent 50%, var(--select-icon) 50%),
    linear-gradient(135deg, var(--select-icon) 50%, transparent 50%);
  background-position:
    right 36px center,
    right 16px center,
    right 11px center;
  background-repeat: no-repeat;
  background-size:
    1px 24px,
    5px 5px,
    5px 5px;
  cursor: pointer;
  font-size: 16px;
}

.multi-select {
  position: relative;
}

.multi-select-control {
  width: 100%;
  min-height: 38px;
  padding: 4px 0 4px 10px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  border: 1px solid var(--control-border);
  border-radius: 4px;
  background: var(--control);
  cursor: pointer;
  text-align: left;
}

.multi-select-control:hover,
.multi-select.is-open .multi-select-control {
  border-color: var(--control-hover);
}

.multi-select-values {
  min-width: 0;
  display: flex;
  align-items: center;
  gap: 4px;
  overflow: hidden;
}

.select-placeholder {
  color: var(--label);
}

.series-chip {
  min-width: 0;
  max-width: 150px;
  padding: 2px 7px;
  display: inline-flex;
  align-items: center;
  gap: 5px;
  color: var(--selected-text);
  background: var(--selected);
  font-size: 14px;
  line-height: 24px;
  white-space: nowrap;
}

.series-chip-label {
  overflow: hidden;
  text-overflow: ellipsis;
}

.series-chip-remove {
  padding: 0;
  border: 0;
  background: transparent;
  color: inherit;
  cursor: pointer;
  font-size: 17px;
  line-height: 1;
}

.select-actions {
  height: 28px;
  flex: 0 0 auto;
  display: flex;
  align-items: center;
}

.select-clear {
  width: 30px;
  padding: 0;
  border: 0;
  background: transparent;
  color: var(--muted);
  cursor: pointer;
  font-size: 22px;
  font-weight: 600;
  line-height: 1;
  text-align: center;
}

.select-separator {
  width: 1px;
  height: 24px;
  background: var(--control-border);
}

.select-chevron {
  width: 34px;
  height: 100%;
  position: relative;
}

.select-chevron::after {
  content: "";
  width: 7px;
  height: 7px;
  position: absolute;
  top: 9px;
  left: 12px;
  border-right: 2px solid var(--select-icon);
  border-bottom: 2px solid var(--select-icon);
  transform: rotate(45deg);
}

.multi-select.is-open .select-chevron::after {
  top: 12px;
  transform: rotate(225deg);
}

.multi-select-menu {
  position: absolute;
  z-index: 20;
  top: calc(100% + 6px);
  left: 0;
  width: 100%;
  max-height: 300px;
  overflow-y: auto;
  border: 1px solid var(--control-border);
  border-radius: 4px;
  background: var(--control);
  box-shadow: 0 4px 12px rgba(0, 0, 0, 0.12);
}

.multi-select-menu button {
  width: 100%;
  min-height: 40px;
  padding: 8px 12px;
  border: 0;
  background: transparent;
  cursor: pointer;
  text-align: left;
}

.multi-select-menu button:hover,
.multi-select-menu button:focus-visible {
  background: var(--menu-hover);
  outline: 0;
}

.multi-select-menu button[aria-selected="true"] {
  color: var(--selected-text);
  background: var(--selected);
}

select:hover {
  border-color: var(--control-hover);
}

select:disabled {
  color: var(--muted);
  background-color: color-mix(in srgb, var(--control) 92%, var(--line));
  cursor: not-allowed;
}

select:focus-visible,
input:focus-visible,
button:focus-visible,
.brand:focus-visible {
  outline: 3px solid var(--focus);
  outline-offset: 2px;
}

.question-search {
  height: 40px;
  margin: 16px 0 0;
  position: relative;
}

.question-search input {
  width: 100%;
  height: 40px;
  padding: 0 46px 0 42px;
  border: 1px solid var(--control-border);
  border-radius: 4px;
  color: var(--control-text);
  background: var(--control);
}

.question-search input:hover,
.question-search input:focus {
  border-color: var(--control-hover);
}

.question-search input::placeholder {
  color: var(--label);
  opacity: 1;
}

.search-icon {
  width: 14px;
  height: 14px;
  position: absolute;
  z-index: 1;
  top: 12px;
  left: 15px;
  border: 2px solid var(--select-icon);
  border-radius: 50%;
  pointer-events: none;
}

.search-icon::after {
  content: "";
  width: 7px;
  height: 2px;
  position: absolute;
  right: -6px;
  bottom: -3px;
  background: var(--select-icon);
  transform: rotate(45deg);
  transform-origin: left center;
}

.search-clear {
  width: 38px;
  height: 38px;
  padding: 0;
  position: absolute;
  top: 1px;
  right: 1px;
  border: 0;
  background: transparent;
  color: var(--muted);
  cursor: pointer;
  font-size: 23px;
  line-height: 1;
}

.results-bar {
  min-height: 166px;
  display: flex;
  align-items: flex-end;
  justify-content: space-between;
  padding: 0 0 8px 5px;
  border-bottom: 1px solid var(--line);
}

.results-bar strong,
.results-bar span {
  display: block;
}

.results-bar strong {
  margin-bottom: 0;
  font-size: 14px;
  font-weight: 300;
}

#filterSummary {
  display: none;
}

.pack-trigger {
  min-height: 38px;
  padding: 0 11px;
  display: inline-flex;
  align-items: center;
  gap: 8px;
  border: 1px solid var(--control-border);
  border-radius: 4px;
  background: var(--control);
  cursor: pointer;
}

.pack-trigger:hover {
  border-color: var(--control-hover);
}

.pack-trigger-icon {
  width: 15px;
  height: 18px;
  position: relative;
  display: block;
  border: 1.5px solid currentColor;
}

.pack-trigger-icon::after {
  content: "";
  width: 7px;
  position: absolute;
  right: 3px;
  bottom: 4px;
  border-bottom: 1.5px solid currentColor;
  box-shadow: 0 -4px 0 currentColor;
}

.pack-count {
  min-width: 22px;
  height: 22px;
  padding: 0 6px;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  border-radius: 11px;
  color: var(--selected-text);
  background: var(--selected);
  font-size: 12px;
}

.question-grid {
  min-height: 465px;
  padding: 8px 0 28px;
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(320px, 1fr));
  gap: 16px;
}

.question-card {
  min-width: 0;
  height: 350px;
  padding: 8px;
  position: relative;
  border: 1px solid var(--line);
  border-radius: 4px;
  color: var(--text);
  background: var(--control);
  overflow: hidden;
  transition: border-color 120ms ease, box-shadow 120ms ease;
}

.question-card:hover {
  border-color: var(--control-hover);
  box-shadow: 0 2px 8px rgba(0, 0, 0, 0.1);
}

.question-card-open {
  width: 100%;
  height: 100%;
  padding: 0;
  display: grid;
  grid-template-rows: 56px 1fr 48px;
  border: 0;
  color: inherit;
  background: transparent;
  cursor: pointer;
  text-align: center;
}

.card-pack-toggle {
  width: 28px;
  height: 28px;
  padding: 0;
  position: absolute;
  z-index: 2;
  top: 12px;
  right: 12px;
  border: 1px solid var(--control-border);
  border-radius: 50%;
  color: var(--text);
  background: var(--control);
  cursor: pointer;
  font-size: 20px;
  line-height: 24px;
}

.card-pack-toggle:hover {
  border-color: var(--text);
}

.card-pack-toggle.is-selected {
  border-color: var(--selected);
  color: var(--selected-text);
  background: var(--selected);
  font-size: 15px;
}

.question-card-heading {
  position: relative;
  display: flex;
  flex-direction: column;
  justify-content: center;
  border-bottom: 1px solid var(--text);
  font-size: 12px;
  line-height: 18px;
}

.question-card-heading strong {
  font-size: 14px;
  font-weight: 400;
}

.question-card-heading small {
  position: absolute;
  right: 2px;
  bottom: 4px;
  color: var(--muted);
  font-size: 11px;
}

.question-preview {
  min-height: 0;
  display: block;
  overflow: hidden;
  background: #ffffff;
}

.question-preview img {
  width: 100%;
  height: auto;
  display: block;
}

.question-card-footer {
  display: flex;
  min-width: 0;
  padding: 4px 6px;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  border-top: 1px solid var(--text);
  font-size: 12px;
  overflow: hidden;
}

.question-card-topic {
  width: 100%;
  overflow: hidden;
  text-overflow: ellipsis;
  white-space: nowrap;
}

.question-card-match {
  width: 100%;
  color: var(--muted);
  font-size: 10px;
  line-height: 14px;
  overflow: hidden;
  text-overflow: ellipsis;
  white-space: nowrap;
}

.empty-library {
  grid-column: 1 / -1;
  min-height: 360px;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  color: var(--muted);
  text-align: center;
}

.empty-library strong {
  color: var(--text);
  font-size: 16px;
}

.question-viewer {
  width: min(1040px, calc(100vw - 36px));
  height: min(94vh, 980px);
  padding: 0;
  border: 1px solid var(--line);
  border-radius: 4px;
  color: var(--text);
  background: var(--page);
  overflow: hidden;
}

.question-viewer::backdrop {
  background: rgba(0, 0, 0, 0.62);
}

.viewer-shell {
  height: 100%;
  display: grid;
  grid-template-rows: auto auto 1fr;
}

.viewer-header {
  min-height: 76px;
  padding: 12px 18px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  border-bottom: 1px solid var(--line);
}

.viewer-header h1 {
  margin: 1px 0 0;
  font-size: 24px;
  font-weight: 400;
}

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

.viewer-pack-toggle,
.primary-button,
.secondary-button {
  min-height: 38px;
  padding: 0 13px;
  border: 1px solid var(--control-border);
  border-radius: 4px;
  background: var(--control);
  cursor: pointer;
}

.viewer-pack-toggle:hover,
.secondary-button:hover {
  border-color: var(--control-hover);
}

.viewer-pack-toggle.is-selected,
.primary-button {
  border-color: var(--selected);
  color: var(--selected-text);
  background: var(--selected);
}

.primary-button:disabled,
.secondary-button:disabled {
  opacity: 0.45;
  cursor: not-allowed;
}

.viewer-kicker {
  color: var(--muted);
  font-size: 13px;
}

.viewer-close {
  width: 38px;
  height: 38px;
  padding: 0;
  border: 0;
  background: transparent;
  cursor: pointer;
  font-size: 32px;
  font-weight: 300;
  line-height: 1;
}

.viewer-tabs {
  padding: 0 18px;
  display: flex;
  gap: 26px;
  border-bottom: 1px solid var(--line);
}

.viewer-tab {
  height: 48px;
  padding: 0;
  border: 0;
  border-bottom: 3px solid transparent;
  background: transparent;
  cursor: pointer;
}

.viewer-tab.is-active {
  border-bottom-color: var(--text);
  font-weight: 600;
}

.viewer-pages {
  padding: 22px;
  overflow: auto;
  background: color-mix(in srgb, var(--page) 88%, var(--line));
}

.viewer-pages img {
  width: min(100%, 900px);
  height: auto;
  margin: 0 auto 18px;
  display: block;
  background: #ffffff;
  box-shadow: 0 1px 5px rgba(0, 0, 0, 0.18);
}

.question-load-sentinel {
  grid-column: 1 / -1;
  min-height: 46px;
  border: 1px solid var(--line);
  background: var(--page);
  color: var(--muted);
  cursor: pointer;
  font: inherit;
}

.question-load-sentinel:hover,
.question-load-sentinel:focus-visible {
  border-color: var(--text);
  color: var(--text);
}

.pack-dialog {
  width: min(760px, calc(100vw - 36px));
  height: min(86vh, 780px);
  padding: 0;
  border: 1px solid var(--line);
  border-radius: 4px;
  color: var(--text);
  background: var(--page);
  overflow: hidden;
}

.pack-dialog::backdrop {
  background: rgba(0, 0, 0, 0.62);
}

.pack-shell {
  height: 100%;
  display: grid;
  grid-template-rows: auto auto 1fr auto;
}

.pack-header {
  min-height: 76px;
  padding: 12px 18px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  border-bottom: 1px solid var(--line);
}

.pack-header h1 {
  margin: 1px 0 0;
  font-size: 24px;
  font-weight: 400;
}

.pack-toolbar {
  min-height: 58px;
  padding: 9px 18px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
  border-bottom: 1px solid var(--line);
}

.pack-option {
  display: flex;
  align-items: center;
  gap: 9px;
  cursor: pointer;
}

.pack-option input {
  width: 18px;
  height: 18px;
  margin: 0;
  accent-color: var(--selected);
}

.pack-list {
  min-height: 0;
  margin: 0;
  padding: 0;
  overflow-y: auto;
  list-style: none;
}

.pack-item {
  min-height: 70px;
  padding: 11px 18px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 18px;
  border-bottom: 1px solid var(--line);
}

.pack-item-details {
  min-width: 0;
  display: flex;
  flex-direction: column;
}

.pack-item-details strong {
  font-size: 15px;
  font-weight: 600;
}

.pack-item-details span {
  overflow: hidden;
  color: var(--muted);
  font-size: 13px;
  text-overflow: ellipsis;
  white-space: nowrap;
}

.pack-item-actions {
  flex: 0 0 auto;
  display: flex;
  align-items: center;
  gap: 5px;
}

.pack-item-actions button {
  width: 34px;
  height: 34px;
  padding: 0;
  border: 1px solid transparent;
  border-radius: 4px;
  background: transparent;
  cursor: pointer;
  font-size: 20px;
  line-height: 1;
}

.pack-item-actions button:hover:not(:disabled) {
  border-color: var(--control-border);
  background: var(--menu-hover);
}

.pack-item-actions button:disabled {
  opacity: 0.25;
  cursor: not-allowed;
}

.pack-empty {
  min-height: 0;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  color: var(--muted);
  text-align: center;
}

.pack-empty strong {
  color: var(--text);
}

.pack-footer {
  min-height: 70px;
  padding: 12px 18px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 18px;
  border-top: 1px solid var(--line);
}

.pack-footer > span {
  color: var(--muted);
  font-size: 14px;
}

body > footer {
  width: auto;
  min-height: 85px;
  margin: 0 15px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  border-top: 1px solid var(--line);
  color: var(--muted);
  font-size: 12px;
}

[hidden] {
  display: none !important;
}

@media (max-width: 980px) {
  .filter-grid { grid-template-columns: repeat(2, minmax(0, 1fr)); }
  .qualification-field { grid-column: 1; grid-row: 1; }
  .subject-field { grid-column: 1; grid-row: 2; }
  .series-field { grid-column: 2; grid-row: 1; }
  .paper-field { grid-column: 2; grid-row: 2; }
  .topic-field { grid-column: 1; grid-row: 3; }
  .subtopic-field { grid-column: 2; grid-row: 3; }

  .series-field,
  .paper-field,
  .subtopic-field {
    margin-left: 16px;
  }

  .topic-field {
    margin-left: 0;
  }
}

@media (max-width: 680px) {
  .site-header,
  main,
  body > footer {
    width: auto;
    margin-left: 15px;
    margin-right: 15px;
  }

  .site-header {
    min-height: 72px;
  }

  .brand {
    font-size: 34px;
  }

  .theme-switcher {
    gap: 10px;
  }

  .theme-swatch {
    width: 22px;
    height: 22px;
  }

  .filters {
    padding: 12px 0 18px;
  }

  .filter-grid { display: block; }
  .filter-field { display: block; margin-bottom: 12px; }

  .series-field,
  .paper-field,
  .topic-field,
  .subtopic-field {
    margin-left: 0;
  }

  .results-bar { min-height: 110px; }

  .pack-trigger > span:nth-child(2) {
    display: none;
  }

  .question-grid {
    grid-template-columns: 1fr;
  }

  .question-card {
    height: 420px;
  }

  .question-viewer {
    width: 100vw;
    height: 100vh;
    max-width: none;
    max-height: none;
    border: 0;
    border-radius: 0;
  }

  .viewer-pages {
    padding: 10px;
  }

  .viewer-header {
    padding-left: 12px;
    padding-right: 8px;
  }

  .viewer-pack-toggle {
    padding: 0 9px;
    font-size: 13px;
  }

  .pack-dialog {
    width: 100vw;
    height: 100vh;
    max-width: none;
    max-height: none;
    border: 0;
    border-radius: 0;
  }

  .pack-item {
    padding-left: 12px;
    padding-right: 8px;
    gap: 8px;
  }

  .pack-item-actions {
    gap: 0;
  }

  .pack-toolbar,
  .pack-footer {
    padding-left: 12px;
    padding-right: 12px;
  }

  body > footer {
    padding: 20px 0;
    flex-direction: column;
    align-items: flex-start;
    justify-content: center;
    gap: 6px;
  }
}