:root {
  color-scheme: light dark;

  --colour-primary: #2563eb;
  --colour-primary-hover: #1d4ed8;
  --colour-primary-light: #dbeafe;
  --colour-bg: #fafafa;
  --colour-bg-secondary: #f4f4f5;
  --colour-bg-tertiary: #e4e4e7;
  --colour-border: #d4d4d8;
  --colour-text: #18181b;
  --colour-text-secondary: #52525b;
  --colour-text-tertiary: #a1a1aa;
  --colour-block-bg: #ffffff;
  --colour-block-border: #e4e4e7;
  --colour-warning: #b45309;
  --colour-warning-bg: #fef3c7;
  --colour-error: #b91c1c;
  --colour-error-bg: #fee2e2;
  --colour-shadow: rgba(0, 0, 0, 0.08);

  --space-xs: 0.25rem;
  --space-sm: 0.5rem;
  --space-md: 0.75rem;
  --space-lg: 1rem;
  --space-xl: 1.5rem;
  --space-2xl: 2rem;
  --radius: 0.5rem;

  --preview-family: system-ui;
  --preview-size: 52px;

  --mono: ui-monospace, "SF Mono", "Cascadia Code", Menlo, Monaco, Consolas, "Liberation Mono", monospace;
}

@media (prefers-color-scheme: dark) {
  :root {
    --colour-primary: #60a5fa;
    --colour-primary-hover: #93c5fd;
    --colour-primary-light: #1e3a8a;
    --colour-bg: #0a0a0a;
    --colour-bg-secondary: #171717;
    --colour-bg-tertiary: #262626;
    --colour-border: #3f3f46;
    --colour-text: #fafafa;
    --colour-text-secondary: #a1a1aa;
    --colour-text-tertiary: #71717a;
    --colour-block-bg: #141414;
    --colour-block-border: #262626;
    --colour-warning: #fbbf24;
    --colour-warning-bg: #2a1f05;
    --colour-error: #fca5a5;
    --colour-error-bg: #2a0d0d;
    --colour-shadow: rgba(0, 0, 0, 0.5);
  }
}

*,
*::before,
*::after {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

[hidden] {
  display: none !important;
}

body {
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
  background: var(--colour-bg);
  color: var(--colour-text);
  line-height: 1.5;
  min-height: 100dvh;
  padding: var(--space-lg);
}

body.dragover::after {
  content: "Drop the font";
  position: fixed;
  inset: var(--space-sm);
  z-index: 20;
  display: grid;
  place-items: center;
  font-size: 1.5rem;
  font-weight: 600;
  color: var(--colour-primary);
  background: color-mix(in srgb, var(--colour-bg) 88%, transparent);
  border: 2px dashed var(--colour-primary);
  border-radius: var(--radius);
}

.container {
  width: 100%;
  max-width: 64rem;
  margin-inline: auto;
}

/* ------------------------------------------------------------- header --- */

.app-header {
  margin-bottom: var(--space-xl);
}

h1 {
  font-family: Georgia, "Times New Roman", Times, serif;
  font-size: 1.75rem;
  letter-spacing: -0.01em;
}

.tagline {
  color: var(--colour-text-secondary);
  max-width: 46rem;
  margin-top: var(--space-xs);
}

/* ------------------------------------------------------------ buttons --- */

.btn {
  font: inherit;
  font-weight: 500;
  padding: var(--space-sm) var(--space-lg);
  border: 1px solid var(--colour-border);
  border-radius: var(--radius);
  background: var(--colour-block-bg);
  color: var(--colour-text);
  cursor: pointer;

  &:hover {
    border-color: var(--colour-primary);
    color: var(--colour-primary);
  }

  &.primary {
    background: var(--colour-primary);
    border-color: var(--colour-primary);
    color: #fff;

    &:hover {
      background: var(--colour-primary-hover);
      border-color: var(--colour-primary-hover);
      color: #fff;
    }
  }

  &.small {
    font-size: 0.875rem;
    padding: var(--space-xs) var(--space-md);
  }

  &.tiny {
    font-size: 0.75rem;
    padding: 0.15rem var(--space-sm);
  }
}

/* ---------------------------------------------------------- dropzone ---- */

.dropzone {
  border: 2px dashed var(--colour-border);
  border-radius: var(--radius);
  background: var(--colour-bg-secondary);
  padding: var(--space-2xl) var(--space-lg);
  text-align: center;
  cursor: pointer;

  &:hover {
    border-color: var(--colour-primary);
  }
}

.dropzone-title {
  font-size: 1.25rem;
  font-weight: 600;
}

.dropzone-hint {
  color: var(--colour-text-secondary);
  font-size: 0.875rem;
  margin-top: var(--space-xs);
}

.dropzone-actions {
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-sm);
  justify-content: center;
  margin-top: var(--space-lg);
}

.status,
.error {
  margin-top: var(--space-lg);
  padding: var(--space-md);
  border-radius: var(--radius);
  background: var(--colour-bg-secondary);
  color: var(--colour-text-secondary);
  font-size: 0.9375rem;
}

.error {
  background: var(--colour-error-bg);
  color: var(--colour-error);
}

/* ------------------------------------------------------------ panels ---- */

.panel,
.summary {
  margin-top: var(--space-xl);
  padding: var(--space-lg);
  background: var(--colour-block-bg);
  border: 1px solid var(--colour-block-border);
  border-radius: var(--radius);
}

.panel-head {
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-sm) var(--space-lg);
  align-items: center;
  justify-content: space-between;
  margin-bottom: var(--space-lg);

  & h2 {
    font-size: 1.125rem;
    font-weight: 600;
  }
}

.count {
  font-weight: 400;
  font-size: 0.875rem;
  color: var(--colour-text-tertiary);
}

.control {
  display: flex;
  align-items: center;
  gap: var(--space-sm);
  font-size: 0.875rem;
  color: var(--colour-text-secondary);

  & select,
  & input[type="search"] {
    font: inherit;
    padding: var(--space-xs) var(--space-sm);
    border: 1px solid var(--colour-input-border, var(--colour-border));
    border-radius: var(--radius);
    background: var(--colour-bg);
    color: var(--colour-text);
    max-width: 100%;
  }
}

.control.checkbox {
  cursor: pointer;
}

/* ----------------------------------------------------------- summary ---- */

.summary-title {
  display: flex;
  flex-wrap: wrap;
  align-items: baseline;
  gap: var(--space-sm);

  & h2 {
    font-family: Georgia, "Times New Roman", Times, serif;
    font-size: 1.5rem;
  }
}

.subfamily {
  color: var(--colour-text-secondary);
}

.badges {
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-xs);
  list-style: none;
  margin-top: var(--space-md);
}

.badge {
  font-size: 0.75rem;
  padding: 0.1rem var(--space-sm);
  border-radius: 999px;
  background: var(--colour-bg-tertiary);
  color: var(--colour-text-secondary);

  &.strong {
    background: var(--colour-primary-light);
    color: var(--colour-primary);
    font-weight: 600;
  }
}

.file-switch {
  margin-top: var(--space-md);
}

.facts-details {
  margin-top: var(--space-md);
  font-size: 0.875rem;

  & summary {
    cursor: pointer;
    color: var(--colour-text-secondary);
  }
}

.facts {
  display: grid;
  grid-template-columns: max-content 1fr;
  gap: var(--space-xs) var(--space-md);
  margin-top: var(--space-sm);

  & dt {
    color: var(--colour-text-tertiary);
  }

  & dd {
    overflow-wrap: anywhere;
  }
}

.notice {
  margin-top: var(--space-md);
  padding: var(--space-sm) var(--space-md);
  border-radius: var(--radius);
  background: var(--colour-bg-secondary);
  color: var(--colour-text-secondary);
  font-size: 0.8125rem;

  &.warning {
    background: var(--colour-warning-bg);
    color: var(--colour-warning);
  }
}

/* ----------------------------------------------------------- preview ---- */

.preview-controls {
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-md);
  align-items: center;
}

.preview-controls output {
  font-variant-numeric: tabular-nums;
  min-width: 3.5em;
}

.preview {
  font-family: var(--preview-family), system-ui, sans-serif;
  font-size: var(--preview-size);
  line-height: 1.2;
  padding: var(--space-md);
  border: 1px dashed var(--colour-border);
  border-radius: var(--radius);
  overflow-wrap: anywhere;
  min-height: 2em;

  &:focus-visible {
    outline: 2px solid var(--colour-primary);
    outline-offset: 2px;
  }
}

/* -------------------------------------------------------------- axes ---- */

.axes {
  display: grid;
  gap: var(--space-lg);
}

.axis-head {
  display: flex;
  justify-content: space-between;
  align-items: baseline;
  gap: var(--space-sm);

  & label {
    display: flex;
    align-items: baseline;
    gap: var(--space-sm);
    font-weight: 500;
  }
}

.axis-value {
  font-family: var(--mono);
  font-size: 0.875rem;
}

.axis input[type="range"] {
  width: 100%;
  accent-color: var(--colour-primary);
}

.axis-range {
  display: flex;
  justify-content: space-between;
  font-size: 0.75rem;
  color: var(--colour-text-tertiary);
  font-family: var(--mono);
}

.axis-note {
  font-size: 0.75rem;
  color: var(--colour-text-tertiary);
}

/* ---------------------------------------------------------- features ---- */

.feature-group {
  margin-bottom: var(--space-xl);

  &:last-child {
    margin-bottom: 0;
  }
}

.group-title {
  font-size: 0.8125rem;
  text-transform: uppercase;
  letter-spacing: 0.06em;
  color: var(--colour-text-tertiary);
  border-bottom: 1px solid var(--colour-border);
  padding-bottom: var(--space-xs);
  margin-bottom: var(--space-md);
}

.feature {
  padding: var(--space-md) 0;
  border-bottom: 1px solid var(--colour-block-border);

  &:last-child {
    border-bottom: 0;
  }
}

.feature-head {
  display: flex;
  gap: var(--space-md);
  align-items: flex-start;
}

.feature-meta h3 {
  display: flex;
  flex-wrap: wrap;
  align-items: baseline;
  gap: var(--space-sm);
  font-size: 1rem;
  font-weight: 600;
}

code.tag {
  font-family: var(--mono);
  font-size: 0.8125rem;
  padding: 0.05rem 0.3rem;
  border-radius: 0.25rem;
  background: var(--colour-bg-tertiary);
}

.feature-badges {
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-xs);
  margin-top: var(--space-xs);
}

.chip {
  font-size: 0.6875rem;
  padding: 0.05rem 0.4rem;
  border-radius: 999px;
  border: 1px solid var(--colour-border);
  color: var(--colour-text-tertiary);

  &.on {
    border-color: var(--colour-primary);
    color: var(--colour-primary);
  }
}

.switch {
  flex: none;
  display: inline-flex;
  cursor: pointer;

  & input {
    position: absolute;
    opacity: 0;
    width: 2.5rem;
    height: 1.5rem;
    cursor: pointer;
  }

  & .switch-track {
    width: 2.5rem;
    height: 1.5rem;
    border-radius: 999px;
    background: var(--colour-bg-tertiary);
    border: 1px solid var(--colour-border);
    position: relative;
    transition: background 0.15s ease;

    &::after {
      content: "";
      position: absolute;
      inset-block: 2px;
      left: 2px;
      width: 1.125rem;
      border-radius: 50%;
      background: var(--colour-block-bg);
      box-shadow: 0 1px 2px var(--colour-shadow);
      transition: translate 0.15s ease;
    }
  }

  & input:checked + .switch-track {
    background: var(--colour-primary);
    border-color: var(--colour-primary);

    &::after {
      translate: 0.95rem 0;
    }
  }

  & input:focus-visible + .switch-track {
    outline: 2px solid var(--colour-primary);
    outline-offset: 2px;
  }
}

.compare {
  display: grid;
  gap: var(--space-sm);
  margin-top: var(--space-md);
}

.pane {
  border: 1px solid var(--colour-block-border);
  border-radius: var(--radius);
  background: var(--colour-bg-secondary);
  padding: var(--space-sm);
  overflow: hidden;
}

.pane-label {
  display: block;
  font-size: 0.6875rem;
  text-transform: uppercase;
  letter-spacing: 0.06em;
  color: var(--colour-text-tertiary);
}

.sample {
  font-family: var(--preview-family), system-ui, sans-serif;
  font-size: min(var(--preview-size), 40px);
  line-height: 1.3;
  overflow-wrap: anywhere;
  white-space: pre-wrap;
}

.alternates {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: var(--space-xs);
  margin-top: var(--space-sm);
}

.alternates-label {
  font-size: 0.75rem;
  color: var(--colour-text-tertiary);
  margin-right: var(--space-xs);
}

.chip-button {
  font: inherit;
  font-size: 0.75rem;
  min-width: 2rem;
  padding: 0.1rem var(--space-sm);
  border: 1px solid var(--colour-border);
  border-radius: var(--radius);
  background: var(--colour-block-bg);
  color: var(--colour-text-secondary);
  cursor: pointer;

  &.active {
    background: var(--colour-primary);
    border-color: var(--colour-primary);
    color: #fff;
  }
}

.characters {
  margin-top: var(--space-sm);
  font-size: 0.8125rem;

  & summary {
    cursor: pointer;
    color: var(--colour-text-secondary);
  }
}

.character-list {
  font-family: var(--preview-family), system-ui, sans-serif;
  font-size: 1.25rem;
  line-height: 1.6;
  margin-top: var(--space-xs);
  overflow-wrap: anywhere;
}

.feature-css {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: var(--space-sm);
  margin-top: var(--space-sm);

  & code {
    font-family: var(--mono);
    font-size: 0.75rem;
    color: var(--colour-text-secondary);
    overflow-wrap: anywhere;
  }
}

.empty-note {
  color: var(--colour-text-secondary);
}

/* --------------------------------------------------------------- code --- */

.code-hint {
  background: var(--colour-bg-secondary);
  border: 1px solid var(--colour-border);
  border-radius: 8px;
  padding: 0.75rem 1rem;
  font-size: 0.82rem;
  color: var(--colour-text-secondary);
  font-family: var(--mono);
  overflow-x: auto;
  line-height: 1.7;

  & code {
    background: none;
    border: none;
    padding: 0;
    font-size: inherit;
    color: inherit;
  }
}

/* ------------------------------------------------------------- footer --- */

.app-footer {
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-sm);
  margin-top: var(--space-xl);
  padding-top: var(--space-lg);
  border-top: 1px solid var(--colour-border);
}

/* ------------------------------------------------------------- dialog --- */

dialog {
  width: min(32rem, 100vw);
  max-height: 90dvh;
  margin: auto;
  padding: 0;
  border: 1px solid var(--colour-border);
  border-radius: var(--radius);
  background: var(--colour-block-bg);
  color: var(--colour-text);
  overflow: hidden;

  &::backdrop {
    background: rgba(0, 0, 0, 0.5);
  }
}

.dialog-head {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: var(--space-md);
  padding: var(--space-md) var(--space-lg);
  border-bottom: 1px solid var(--colour-border);

  & h2 {
    font-size: 1.125rem;
  }
}

.dialog-body {
  padding: var(--space-md) var(--space-lg) var(--space-lg);
  display: flex;
  flex-direction: column;
  gap: var(--space-sm);
  max-height: calc(90dvh - 4rem);
}

.search input {
  width: 100%;
}

.dialog-note {
  font-size: 0.75rem;
  color: var(--colour-text-tertiary);
}

.font-list {
  list-style: none;
  overflow-y: auto;
  flex: 1;
  min-height: 12rem;
}

.font-row {
  display: flex;
  justify-content: space-between;
  align-items: baseline;
  gap: var(--space-md);
  width: 100%;
  font: inherit;
  text-align: left;
  padding: var(--space-sm);
  border: 0;
  border-radius: var(--radius);
  background: none;
  color: inherit;
  cursor: pointer;

  &:hover {
    background: var(--colour-bg-secondary);
  }
}

.font-tags {
  font-size: 0.75rem;
  color: var(--colour-text-tertiary);
  flex: none;
}

.visually-hidden {
  position: absolute;
  width: 1px;
  height: 1px;
  overflow: hidden;
  clip-path: inset(50%);
  white-space: nowrap;
}

/* --------------------------------------------------------- responsive --- */

@media (max-width: 639px) {
  dialog {
    inset: 0;
    margin: 0;
    width: 100vw;
    height: 100dvh;
    max-width: 100vw;
    max-height: 100dvh;
    border-radius: 0;
  }

  .dialog-body {
    max-height: none;
    flex: 1;
  }
}

@media (min-width: 640px) {
  body {
    padding: var(--space-2xl) var(--space-lg);
  }

  h1 {
    font-size: 2rem;
  }

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

  .panel,
  .summary {
    padding: var(--space-xl);
  }
}