/* ==========================================================================
   Michael Hayden Portfolio — Design System
   Premium, cohesive foundation: typography, color, spacing, borders,
   shadows, iconography, and reusable components. Fonts are loaded per page.
   ========================================================================== */

:root {
  color-scheme: light;

  /* Typography: families */
  --font-display: "Space Grotesk", "Segoe UI", system-ui, sans-serif;
  --font-body: "IBM Plex Sans", "Segoe UI", system-ui, sans-serif;
  --font-mono: "IBM Plex Mono", ui-monospace, "SFMono-Regular", Menlo, monospace;

  /* Typography: weights */
  --weight-regular: 400;
  --weight-medium: 500;
  --weight-semibold: 600;
  --weight-bold: 700;

  /* Typography: line heights */
  --line-height-tight: 1.12;
  --line-height-snug: 1.32;
  --line-height-body: 1.65;

  /* Typography: letter spacing */
  --tracking-tight: -0.02em;
  --tracking-normal: 0;
  --tracking-wide: 0.04em;
  --tracking-caps: 0.12em;

  /* Typography: fluid modular scale (~1.2 minor third) */
  --fs-50: 0.6875rem;
  --fs-100: 0.75rem;
  --fs-200: 0.875rem;
  --fs-300: 1rem;
  --fs-400: 1.125rem;
  --fs-500: clamp(1.2rem, 0.6vw + 1.05rem, 1.35rem);
  --fs-600: clamp(1.45rem, 1.6vw + 1.1rem, 1.95rem);
  --fs-700: clamp(1.85rem, 3vw + 1rem, 2.6rem);
  --fs-800: clamp(2.3rem, 4.4vw + 1rem, 3.4rem);
  --fs-900: clamp(2.8rem, 6vw + 1rem, 4.5rem);

  /* Spacing scale (4px base) */
  --space-1: 0.25rem;
  --space-2: 0.5rem;
  --space-3: 0.75rem;
  --space-4: 1rem;
  --space-5: 1.25rem;
  --space-6: 1.5rem;
  --space-7: 2rem;
  --space-8: 2.75rem;
  --space-9: 4rem;
  --space-10: 5.5rem;
  --space-11: 7rem;

  /* Border radius */
  --radius-xs: 6px;
  --radius-sm: 10px;
  --radius-md: 14px;
  --radius-lg: 20px;
  --radius-xl: 28px;
  --radius-2xl: 36px;
  --radius-pill: 999px;

  /* Border widths */
  --border-hairline: 1px;
  --border-thick: 1.5px;

  /* Color primitives: neutral (cool slate) */
  --neutral-0: #ffffff;
  --neutral-50: #f5f8fb;
  --neutral-100: #eaf0f6;
  --neutral-200: #d7e1ec;
  --neutral-300: #b9c8d8;
  --neutral-400: #8ca0b4;
  --neutral-500: #647a90;
  --neutral-600: #4a6076;
  --neutral-700: #364b5f;
  --neutral-800: #22384b;
  --neutral-900: #122334;
  --neutral-950: #091522;

  /* Color primitives: brand (teal/cyan) */
  --brand-50: #e6f7fa;
  --brand-100: #c2ecf2;
  --brand-200: #8fdbe6;
  --brand-300: #57c4d4;
  --brand-400: #2aa7bd;
  --brand-500: #0d8a9f;
  --brand-600: #0b7184;
  --brand-700: #0a5b6b;
  --brand-800: #0a4654;
  --brand-900: #093743;

  /* Color primitives: state */
  --color-success: #1f9d6b;
  --color-success-soft: rgba(31, 157, 107, 0.14);
  --color-warning: #c98a18;
  --color-warning-soft: rgba(201, 138, 24, 0.16);
  --color-danger: #cf4b46;
  --color-danger-soft: rgba(207, 75, 70, 0.14);
  --color-info: #2f78c4;
  --color-info-soft: rgba(47, 120, 196, 0.14);

  /* Semantic surfaces & text (light) */
  --bg-page: #f2f6fa;
  --bg-elevated: rgba(255, 255, 255, 0.94);
  --bg-elevated-solid: #ffffff;
  --bg-muted: #e5edf4;
  --bg-inset: #eef3f8;
  --text-primary: #0f2439;
  --text-secondary: #2f4b66;
  --text-muted: #4d6880;
  --text-inverse: #f5f8fb;
  --text-on-accent: #ffffff;

  /* Accent (mapped to brand for backward compatibility) */
  --accent: var(--brand-500);
  --accent-strong: var(--brand-700);
  --accent-soft: rgba(13, 138, 159, 0.12);
  --accent-contrast: #ffffff;

  /* Borders */
  --border-soft: rgba(16, 41, 65, 0.12);
  --border-strong: rgba(16, 41, 65, 0.24);
  --focus-ring: rgba(13, 138, 159, 0.32);

  /* Motion */
  --duration-xfast: 110ms;
  --duration-fast: 160ms;
  --duration-medium: 240ms;
  --duration-slow: 420ms;
  --ease-standard: cubic-bezier(0.2, 0, 0.1, 1);
  --ease-emphasized: cubic-bezier(0.2, 0.7, 0.1, 1);
  --ease-out: cubic-bezier(0, 0, 0.2, 1);
  /* Gentle, professional settle (no overshoot) for entrances and hovers. */
  --ease-entrance: cubic-bezier(0.22, 1, 0.36, 1);

  /* Elevation (shadows) */
  --shadow-xs: 0 1px 2px rgba(10, 30, 49, 0.06), 0 1px 1px rgba(10, 30, 49, 0.04);
  --shadow-sm: 0 6px 16px rgba(10, 30, 49, 0.08), 0 1px 2px rgba(10, 30, 49, 0.04);
  --shadow-md: 0 14px 32px rgba(10, 30, 49, 0.1), 0 2px 6px rgba(10, 30, 49, 0.05);
  --shadow-lg: 0 24px 50px rgba(10, 30, 49, 0.14), 0 4px 10px rgba(10, 30, 49, 0.06);
  --shadow-xl: 0 36px 72px rgba(10, 30, 49, 0.18);
  --shadow-glow: 0 14px 36px rgba(13, 138, 159, 0.28);
  --shadow-inset: inset 0 1px 0 rgba(255, 255, 255, 0.6);

  /* Layout */
  --layout-max: 1080px;
  --layout-wide: 1240px;
  --layout-gutter: clamp(1.1rem, 3.5vw, 2.4rem);

  /* Icon sizing */
  --icon-sm: 1rem;
  --icon-md: 1.25rem;
  --icon-lg: 1.75rem;
  --icon-stroke: 1.75;
}

[data-theme="dark"] {
  color-scheme: dark;
  --bg-page: #091522;
  --bg-elevated: rgba(13, 30, 46, 0.92);
  --bg-elevated-solid: #102438;
  --bg-muted: #10263c;
  --bg-inset: #0c1f31;
  --text-primary: #deecf7;
  --text-secondary: #bfd3e4;
  --text-muted: #98b2c7;
  --text-inverse: #091522;
  --text-on-accent: #04222a;

  --accent: #44c4d7;
  --accent-strong: #1ea7ba;
  --accent-soft: rgba(68, 196, 215, 0.16);
  --accent-contrast: #04222a;

  --color-success: #3ec88c;
  --color-success-soft: rgba(62, 200, 140, 0.18);
  --color-warning: #e6b45a;
  --color-warning-soft: rgba(230, 180, 90, 0.2);
  --color-danger: #f0746e;
  --color-danger-soft: rgba(240, 116, 110, 0.18);
  --color-info: #67a8ec;
  --color-info-soft: rgba(103, 168, 236, 0.18);

  --border-soft: rgba(163, 199, 226, 0.18);
  --border-strong: rgba(163, 199, 226, 0.34);
  --focus-ring: rgba(68, 196, 215, 0.4);

  --shadow-xs: 0 1px 2px rgba(0, 0, 0, 0.4);
  --shadow-sm: 0 8px 20px rgba(0, 0, 0, 0.4);
  --shadow-md: 0 16px 36px rgba(0, 0, 0, 0.46);
  --shadow-lg: 0 28px 58px rgba(0, 0, 0, 0.52);
  --shadow-xl: 0 40px 80px rgba(0, 0, 0, 0.58);
  --shadow-glow: 0 16px 40px rgba(68, 196, 215, 0.32);
  --shadow-inset: inset 0 1px 0 rgba(255, 255, 255, 0.06);
}

@media (prefers-color-scheme: dark) {
  :root:not([data-theme="light"]) {
    color-scheme: dark;
    --bg-page: #091522;
    --bg-elevated: rgba(13, 30, 46, 0.92);
    --bg-elevated-solid: #102438;
    --bg-muted: #10263c;
    --bg-inset: #0c1f31;
    --text-primary: #deecf7;
    --text-secondary: #bfd3e4;
    --text-muted: #98b2c7;
    --text-inverse: #091522;
    --text-on-accent: #04222a;

    --accent: #44c4d7;
    --accent-strong: #1ea7ba;
    --accent-soft: rgba(68, 196, 215, 0.16);
    --accent-contrast: #04222a;

    --color-success: #3ec88c;
    --color-success-soft: rgba(62, 200, 140, 0.18);
    --color-warning: #e6b45a;
    --color-warning-soft: rgba(230, 180, 90, 0.2);
    --color-danger: #f0746e;
    --color-danger-soft: rgba(240, 116, 110, 0.18);
    --color-info: #67a8ec;
    --color-info-soft: rgba(103, 168, 236, 0.18);

    --border-soft: rgba(163, 199, 226, 0.18);
    --border-strong: rgba(163, 199, 226, 0.34);
    --focus-ring: rgba(68, 196, 215, 0.4);

    --shadow-xs: 0 1px 2px rgba(0, 0, 0, 0.4);
    --shadow-sm: 0 8px 20px rgba(0, 0, 0, 0.4);
    --shadow-md: 0 16px 36px rgba(0, 0, 0, 0.46);
    --shadow-lg: 0 28px 58px rgba(0, 0, 0, 0.52);
    --shadow-xl: 0 40px 80px rgba(0, 0, 0, 0.58);
    --shadow-glow: 0 16px 40px rgba(68, 196, 215, 0.32);
    --shadow-inset: inset 0 1px 0 rgba(255, 255, 255, 0.06);
  }
}

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

html {
  -webkit-text-size-adjust: 100%;
  text-size-adjust: 100%;
  scroll-behavior: smooth;
}

html,
body {
  margin: 0;
  padding: 0;
  /* Guard against horizontal scroll from full-bleed effects on small screens. */
  overflow-x: hidden;
}

body {
  font-family: var(--font-body);
  font-size: var(--fs-300);
  line-height: var(--line-height-body);
  color: var(--text-primary);
  background: var(--bg-page);
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  font-feature-settings: "kern" 1, "liga" 1, "calt" 1;
  text-rendering: optimizeLegibility;
  -webkit-tap-highlight-color: rgba(13, 138, 159, 0.16);
}

/* Media never forces an overflow on narrow viewports. */
img,
svg,
video,
canvas {
  height: auto;
}

h1,
h2,
h3,
h4,
h5,
h6 {
  margin: 0;
  font-family: var(--font-display);
  font-weight: var(--weight-bold);
  color: var(--text-primary);
  line-height: var(--line-height-tight);
  letter-spacing: var(--tracking-tight);
  text-wrap: balance;
}

h1 {
  font-size: var(--fs-800);
}

h2 {
  font-size: var(--fs-600);
}

h3 {
  font-size: var(--fs-500);
}

h4 {
  font-size: var(--fs-400);
  line-height: var(--line-height-snug);
}

p,
ul,
ol {
  margin: 0;
}

p {
  text-wrap: pretty;
}

a {
  color: var(--accent);
  text-decoration-thickness: 1px;
  text-underline-offset: 0.18em;
  transition: color var(--duration-fast) var(--ease-standard);
}

a:hover {
  color: var(--accent-strong);
}

img,
svg,
video {
  max-width: 100%;
}

code,
kbd,
samp,
pre {
  font-family: var(--font-mono);
  font-size: 0.92em;
}

hr {
  border: 0;
  border-top: var(--border-hairline) solid var(--border-soft);
  margin: var(--space-6) 0;
}

::selection {
  background: var(--accent-soft);
  color: var(--text-primary);
}

:where(a, button, input, textarea, select, summary, [tabindex]):focus-visible {
  outline: 3px solid var(--focus-ring);
  outline-offset: 2px;
  border-radius: var(--radius-xs);
}

.container,
.u-container {
  width: min(var(--layout-max), calc(100% - (var(--layout-gutter) * 2)));
  margin-inline: auto;
}

.u-container-wide {
  width: min(var(--layout-wide), calc(100% - (var(--layout-gutter) * 2)));
  margin-inline: auto;
}

.eyebrow,
.overline {
  margin: 0;
  display: inline-flex;
  align-items: center;
  gap: var(--space-2);
  text-transform: uppercase;
  letter-spacing: var(--tracking-caps);
  font-size: var(--fs-100);
  font-weight: var(--weight-bold);
  color: var(--text-muted);
}

.eyebrow--accent,
.overline--accent {
  color: var(--accent);
}

.lead {
  font-size: var(--fs-400);
  line-height: var(--line-height-snug);
  color: var(--text-secondary);
  max-width: 62ch;
}

.prose {
  max-width: 68ch;
  color: var(--text-secondary);
}

.prose > * + * {
  margin-top: var(--space-4);
}

.prose strong {
  color: var(--text-primary);
  font-weight: var(--weight-semibold);
}

.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: var(--space-2);
  width: fit-content;
  padding: 0.7rem 1.15rem;
  border-radius: var(--radius-pill);
  border: var(--border-hairline) solid transparent;
  text-decoration: none;
  font: inherit;
  font-weight: var(--weight-semibold);
  line-height: 1;
  letter-spacing: 0.01em;
  cursor: pointer;
  white-space: nowrap;
  transition: transform var(--duration-fast) var(--ease-emphasized), box-shadow var(--duration-fast) var(--ease-standard), background-color var(--duration-fast) var(--ease-standard), border-color var(--duration-fast) var(--ease-standard), color var(--duration-fast) var(--ease-standard);
}

.btn:hover {
  transform: translateY(-1px);
}

.btn:active {
  transform: translateY(0);
}

.btn:focus-visible {
  outline: 3px solid var(--focus-ring);
  outline-offset: 2px;
}

.btn--primary {
  background: linear-gradient(120deg, var(--accent), var(--accent-strong));
  color: var(--accent-contrast);
  box-shadow: var(--shadow-glow);
}

.btn--primary:hover {
  box-shadow: var(--shadow-lg);
}

.btn--secondary {
  background: color-mix(in srgb, var(--bg-elevated) 88%, transparent);
  border-color: var(--border-soft);
  color: var(--text-primary);
  box-shadow: var(--shadow-xs);
}

.btn--secondary:hover {
  border-color: var(--border-strong);
  box-shadow: var(--shadow-sm);
}

.btn--ghost {
  background: transparent;
  border-color: var(--border-strong);
  color: var(--text-secondary);
}

.btn--ghost:hover {
  background: var(--accent-soft);
  border-color: var(--accent);
  color: var(--accent-strong);
}

.btn--sm {
  padding: 0.46rem 0.85rem;
  font-size: var(--fs-200);
}

.btn--lg {
  padding: 0.9rem 1.5rem;
  font-size: var(--fs-400);
}

.btn--block {
  width: 100%;
}

.btn--icon {
  padding: 0.55rem;
  aspect-ratio: 1;
}

.btn[disabled],
.btn[aria-disabled="true"] {
  opacity: 0.55;
  cursor: not-allowed;
  transform: none;
  box-shadow: none;
}

.icon {
  display: inline-block;
  flex: none;
  width: var(--icon-md);
  height: var(--icon-md);
  vertical-align: middle;
  fill: none;
  stroke: currentColor;
  stroke-width: var(--icon-stroke);
  stroke-linecap: round;
  stroke-linejoin: round;
}

.icon--sm {
  width: var(--icon-sm);
  height: var(--icon-sm);
}

.icon--lg {
  width: var(--icon-lg);
  height: var(--icon-lg);
}

.icon-tile {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 2.75rem;
  height: 2.75rem;
  border-radius: var(--radius-md);
  background: var(--accent-soft);
  color: var(--accent-strong);
  border: var(--border-hairline) solid var(--border-soft);
}

.card,
.panel,
.surface-card,
.project-card,
.topic-card,
.focus-card,
.project-panel,
.detail-panel {
  border-radius: var(--radius-lg);
  background: var(--bg-elevated);
  border: var(--border-hairline) solid var(--border-soft);
  box-shadow: var(--shadow-sm);
}

.card,
.panel,
.surface-card {
  padding: var(--space-6);
}

.card--inset {
  background: var(--bg-inset);
  box-shadow: none;
}

.card--feature {
  box-shadow: var(--shadow-md);
}

.divider {
  height: var(--border-hairline);
  border: 0;
  background: linear-gradient(90deg, transparent, var(--border-strong), transparent);
  margin: 0;
}

.avatar {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 3rem;
  height: 3rem;
  border-radius: 50%;
  object-fit: cover;
  background: var(--bg-muted);
  border: var(--border-thick) solid var(--bg-elevated-solid);
  box-shadow: var(--shadow-xs);
}

.badge,
.chip,
.tag {
  display: inline-flex;
  align-items: center;
  gap: var(--space-2);
  font-size: var(--fs-100);
  font-weight: var(--weight-semibold);
  line-height: 1;
}

.badge {
  padding: 0.35rem 0.7rem;
  border-radius: var(--radius-pill);
  background: var(--accent-soft);
  color: var(--accent-strong);
  border: var(--border-hairline) solid color-mix(in srgb, var(--accent) 24%, transparent);
}

.tag {
  padding: 0.4rem 0.75rem;
  border-radius: var(--radius-sm);
  background: var(--bg-muted);
  color: var(--text-secondary);
  border: var(--border-hairline) solid var(--border-soft);
}

.chip {
  padding: 0.4rem 0.85rem;
  border-radius: var(--radius-pill);
  background: color-mix(in srgb, var(--bg-elevated) 90%, transparent);
  color: var(--text-secondary);
  border: var(--border-hairline) solid var(--border-soft);
}

.tag-list {
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-2);
  padding: 0;
  margin: 0;
  list-style: none;
}

.status {
  display: inline-flex;
  align-items: center;
  gap: var(--space-2);
  padding: 0.32rem 0.7rem;
  border-radius: var(--radius-pill);
  font-size: var(--fs-100);
  font-weight: var(--weight-semibold);
}

.status::before {
  content: "";
  width: 0.5rem;
  height: 0.5rem;
  border-radius: 50%;
  background: currentColor;
}

.status--success {
  background: var(--color-success-soft);
  color: var(--color-success);
}

.status--warning {
  background: var(--color-warning-soft);
  color: var(--color-warning);
}

.status--danger {
  background: var(--color-danger-soft);
  color: var(--color-danger);
}

.status--info {
  background: var(--color-info-soft);
  color: var(--color-info);
}

.stat {
  display: grid;
  gap: var(--space-1);
}

.stat__value {
  font-family: var(--font-display);
  font-size: var(--fs-700);
  font-weight: var(--weight-bold);
  line-height: 1;
  color: var(--text-primary);
  letter-spacing: var(--tracking-tight);
}

.stat__label {
  font-size: var(--fs-100);
  font-weight: var(--weight-semibold);
  text-transform: uppercase;
  letter-spacing: var(--tracking-wide);
  color: var(--text-muted);
}

.contact-form,
.form-stack {
  display: grid;
  gap: var(--space-5);
}

.form-field,
.contact-form label {
  display: grid;
  gap: var(--space-2);
  font-size: var(--fs-200);
  font-weight: var(--weight-semibold);
  color: var(--text-secondary);
}

.contact-form input,
.contact-form textarea,
.contact-form select {
  width: 100%;
  border-radius: var(--radius-sm);
  border: var(--border-hairline) solid var(--border-strong);
  padding: 0.74rem 0.9rem;
  background: color-mix(in srgb, var(--bg-elevated) 96%, transparent);
  color: var(--text-primary);
  font: inherit;
  transition: border-color var(--duration-fast) var(--ease-standard), box-shadow var(--duration-fast) var(--ease-standard);
}

.contact-form input::placeholder,
.contact-form textarea::placeholder {
  color: var(--text-muted);
}

.contact-form input:focus,
.contact-form textarea:focus,
.contact-form select:focus {
  outline: none;
  border-color: var(--accent);
  box-shadow: 0 0 0 4px var(--focus-ring);
}

.form-help {
  font-size: var(--fs-100);
  font-weight: var(--weight-regular);
  color: var(--text-muted);
}

.form-error {
  font-size: var(--fs-100);
  font-weight: var(--weight-semibold);
  color: var(--color-danger);
}

.u-grid {
  display: grid;
  gap: var(--space-4);
}

.u-grid-2 {
  display: grid;
  gap: var(--space-5);
  grid-template-columns: repeat(2, minmax(0, 1fr));
}

.u-grid-3 {
  display: grid;
  gap: var(--space-5);
  grid-template-columns: repeat(3, minmax(0, 1fr));
}

.u-grid-auto {
  display: grid;
  gap: var(--space-5);
  grid-template-columns: repeat(auto-fit, minmax(min(100%, 240px), 1fr));
}

.u-stack > * + * {
  margin-top: var(--space-4);
}

.u-stack-sm > * + * {
  margin-top: var(--space-2);
}

.u-stack-lg > * + * {
  margin-top: var(--space-6);
}

.u-cluster {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: var(--space-3);
}

.u-section {
  padding-block: var(--space-9);
}

.u-section-lg {
  padding-block: var(--space-10);
}

.motion-lift {
  transition: transform var(--duration-fast) var(--ease-emphasized), box-shadow var(--duration-fast) var(--ease-standard);
}

.motion-lift:hover {
  transform: translateY(-3px);
  box-shadow: var(--shadow-md);
}

.u-animate-fade-up {
  opacity: 0;
  transform: translateY(12px);
  animation: ds-fade-up var(--duration-medium) var(--ease-out) forwards;
}

@keyframes ds-fade-up {
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

.u-text-muted {
  color: var(--text-muted);
}

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

.u-text-accent {
  color: var(--accent);
}

.u-text-balance {
  text-wrap: balance;
}

.u-visually-hidden {
  position: absolute;
  width: 1px;
  height: 1px;
  padding: 0;
  margin: -1px;
  overflow: hidden;
  clip: rect(0, 0, 0, 0);
  white-space: nowrap;
  border: 0;
}

/* ==========================================================================
   Site navigation
   ========================================================================== */

.skip-link {
  position: absolute;
  left: 50%;
  top: var(--space-2);
  transform: translateX(-50%) translateY(-160%);
  z-index: 1000;
  padding: 0.65rem 1.1rem;
  border-radius: var(--radius-pill);
  background: var(--accent);
  color: var(--accent-contrast);
  font-weight: var(--weight-semibold);
  text-decoration: none;
  box-shadow: var(--shadow-md);
  transition: transform var(--duration-medium) var(--ease-emphasized);
}

.skip-link:focus-visible {
  transform: translateX(-50%) translateY(0);
  color: var(--accent-contrast);
  outline: 3px solid var(--focus-ring);
  outline-offset: 2px;
}

.site-nav {
  position: sticky;
  top: 0;
  z-index: 900;
  background: color-mix(in srgb, var(--bg-page) 86%, transparent);
  -webkit-backdrop-filter: saturate(150%) blur(14px);
  backdrop-filter: saturate(150%) blur(14px);
  border-bottom: var(--border-hairline) solid transparent;
  transition: background-color var(--duration-medium) var(--ease-standard),
    border-color var(--duration-medium) var(--ease-standard),
    box-shadow var(--duration-medium) var(--ease-standard);
}

.site-nav[data-scrolled] {
  background: color-mix(in srgb, var(--bg-page) 94%, transparent);
  border-bottom-color: var(--border-soft);
  box-shadow: var(--shadow-sm);
}

.site-nav__inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: var(--space-5);
  min-height: 4.25rem;
  padding-block: var(--space-3);
}

.site-nav__brand {
  display: inline-flex;
  align-items: center;
  gap: var(--space-3);
  font-family: var(--font-display);
  font-weight: var(--weight-bold);
  font-size: var(--fs-400);
  letter-spacing: var(--tracking-tight);
  color: var(--text-primary);
  text-decoration: none;
  transition: color var(--duration-fast) var(--ease-standard);
}

.site-nav__brand:hover {
  color: var(--text-primary);
}

.site-nav__brand-mark {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 2.3rem;
  height: 2.3rem;
  border-radius: var(--radius-md);
  overflow: hidden;
  box-shadow: var(--shadow-glow);
}

.site-nav__brand-mark img {
  display: block;
  width: 100%;
  height: 100%;
  object-fit: cover;
}

.site-nav__menu {
  display: flex;
  align-items: center;
  gap: var(--space-6);
}

.site-nav__links {
  display: flex;
  align-items: center;
  gap: var(--space-2);
  margin: 0;
  padding: 0;
  list-style: none;
}

.site-nav__links a {
  position: relative;
  display: inline-flex;
  align-items: center;
  padding: 0.5rem 0.8rem;
  border-radius: var(--radius-sm);
  color: var(--text-secondary);
  font-weight: var(--weight-semibold);
  font-size: var(--fs-200);
  text-decoration: none;
  transition: color var(--duration-fast) var(--ease-standard),
    background-color var(--duration-fast) var(--ease-standard);
}

.site-nav__links a::after {
  content: "";
  position: absolute;
  left: 0.8rem;
  right: 0.8rem;
  bottom: 0.32rem;
  height: 2px;
  border-radius: var(--radius-pill);
  background: var(--accent);
  transform: scaleX(0);
  transform-origin: left center;
  transition: transform var(--duration-medium) var(--ease-emphasized);
}

.site-nav__links a:hover {
  color: var(--text-primary);
  background: color-mix(in srgb, var(--bg-elevated) 70%, transparent);
}

.site-nav__links a:hover::after {
  transform: scaleX(1);
}

.site-nav__links a[aria-current="page"] {
  color: var(--accent-strong);
}

.site-nav__links a[aria-current="page"]::after {
  transform: scaleX(1);
}

.site-nav__cta {
  flex: none;
}

.site-nav__toggle {
  display: none;
  align-items: center;
  justify-content: center;
  width: 2.75rem;
  height: 2.75rem;
  padding: 0;
  border-radius: var(--radius-sm);
  border: var(--border-hairline) solid var(--border-soft);
  background: color-mix(in srgb, var(--bg-elevated) 80%, transparent);
  color: var(--text-primary);
  cursor: pointer;
  transition: border-color var(--duration-fast) var(--ease-standard),
    background-color var(--duration-fast) var(--ease-standard);
}

.site-nav__toggle:hover {
  border-color: var(--border-strong);
}

.site-nav__toggle-bars {
  position: relative;
  display: block;
  width: 1.2rem;
  height: 0.8rem;
}

.site-nav__toggle-bars span {
  position: absolute;
  left: 0;
  width: 100%;
  height: 2px;
  border-radius: var(--radius-pill);
  background: currentColor;
  transition: transform var(--duration-medium) var(--ease-emphasized),
    opacity var(--duration-fast) var(--ease-standard);
}

.site-nav__toggle-bars span:nth-child(1) {
  top: 0;
}

.site-nav__toggle-bars span:nth-child(2) {
  top: 50%;
  transform: translateY(-50%);
}

.site-nav__toggle-bars span:nth-child(3) {
  bottom: 0;
}

.site-nav[data-open] .site-nav__toggle-bars span:nth-child(1) {
  top: 50%;
  transform: translateY(-50%) rotate(45deg);
}

.site-nav[data-open] .site-nav__toggle-bars span:nth-child(2) {
  opacity: 0;
}

.site-nav[data-open] .site-nav__toggle-bars span:nth-child(3) {
  bottom: auto;
  top: 50%;
  transform: translateY(-50%) rotate(-45deg);
}

/* Right-aligned controls (theme toggle + mobile menu button). */
.site-nav__controls {
  display: inline-flex;
  align-items: center;
  gap: var(--space-2);
}

.site-nav__theme-toggle {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 2.6rem;
  height: 2.6rem;
  padding: 0;
  border-radius: var(--radius-sm);
  border: var(--border-hairline) solid var(--border-soft);
  background: color-mix(in srgb, var(--bg-elevated) 80%, transparent);
  color: var(--text-secondary);
  cursor: pointer;
  transition: border-color var(--duration-fast) var(--ease-standard),
    background-color var(--duration-fast) var(--ease-standard),
    color var(--duration-fast) var(--ease-standard),
    transform var(--duration-fast) var(--ease-standard);
}

.site-nav__theme-toggle:hover {
  border-color: var(--border-strong);
  color: var(--accent-strong);
}

.site-nav__theme-toggle:active {
  transform: scale(0.94);
}

.site-nav__theme-toggle:focus-visible {
  outline: 2px solid var(--accent);
  outline-offset: 2px;
}

.site-nav__theme-icon {
  width: 1.2rem;
  height: 1.2rem;
}

/* Show the sun in dark theme (switch to light), the moon in light theme. */
.site-nav__theme-icon--moon {
  display: none;
}

[data-theme="light"] .site-nav__theme-icon--sun {
  display: none;
}

[data-theme="light"] .site-nav__theme-icon--moon {
  display: block;
}

@media (min-width: 821px) {
  .site-nav__menu {
    margin-left: auto;
  }
}

@media (max-width: 820px) {
  .site-nav__toggle {
    display: inline-flex;
  }

  .site-nav__menu {
    position: absolute;
    inset: 100% 0 auto 0;
    flex-direction: column;
    align-items: stretch;
    gap: var(--space-4);
    padding: var(--space-5) var(--layout-gutter) var(--space-6);
    background: var(--bg-elevated-solid);
    border-bottom: var(--border-hairline) solid var(--border-soft);
    box-shadow: var(--shadow-lg);
    opacity: 0;
    visibility: hidden;
    transform: translateY(-10px);
    transition: opacity var(--duration-medium) var(--ease-standard),
      transform var(--duration-medium) var(--ease-emphasized),
      visibility 0s linear var(--duration-medium);
  }

  .site-nav[data-open] .site-nav__menu {
    opacity: 1;
    visibility: visible;
    transform: translateY(0);
    transition: opacity var(--duration-medium) var(--ease-standard),
      transform var(--duration-medium) var(--ease-emphasized);
  }

  .site-nav__links {
    flex-direction: column;
    align-items: stretch;
    gap: var(--space-1);
  }

  .site-nav__links a {
    padding: 0.8rem 0.75rem;
    font-size: var(--fs-300);
    border-radius: var(--radius-sm);
  }

  .site-nav__links a::after {
    display: none;
  }

  .site-nav__links a[aria-current="page"] {
    background: var(--accent-soft);
  }

  .site-nav__cta {
    width: 100%;
  }
}

:where(section, header, main, article)[id],
#main-content {
  scroll-margin-top: 5.5rem;
}

#main-content:focus {
  outline: none;
}

/* Grids never overflow their track on small screens. */
.u-grid-2 > *,
.u-grid-3 > *,
.u-grid-auto > * {
  min-width: 0;
}

@media (max-width: 900px) {
  .u-grid-3 {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }
}

@media (max-width: 760px) {
  :root {
    /* Tighter section rhythm reclaims vertical space on phones. */
    --space-10: 4.25rem;
    --space-11: 5rem;
  }

  .u-grid-2,
  .u-grid-3 {
    grid-template-columns: 1fr;
  }

  .u-hide-mobile {
    display: none !important;
  }

  /* Comfortable, thumb-friendly tap targets across interactive elements. */
  .btn {
    min-height: 2.75rem;
  }

  .btn--sm {
    min-height: 2.4rem;
  }

  :where(.site-nav__links a, .tag, .chip, .badge) {
    touch-action: manipulation;
  }

  /* Anchored sections clear the sticky header when jumped to. */
  :where(section, header, main, article)[id],
  #main-content {
    scroll-margin-top: 4.75rem;
  }
}

@media (min-width: 761px) {
  .u-hide-desktop {
    display: none !important;
  }
}

/* Small phones: tighten spacing further and make CTAs full-width. */
@media (max-width: 480px) {
  :root {
    --layout-gutter: 1.05rem;
    --space-9: 3rem;
    --space-10: 3.5rem;
    --space-11: 4rem;
  }

  .btn--block-mobile,
  .u-stack-actions > .btn {
    width: 100%;
  }

  .lead {
    font-size: var(--fs-300);
  }
}

/* ==========================================================================
   Scroll reveal — tasteful entrance animations as content enters the viewport.
   Elements are hidden via CSS from first paint (no flash); the shared
   navigation script adds [data-revealed] when the element scrolls into view.
   A <noscript> override in the document head keeps content visible without JS.
   ========================================================================== */

[data-reveal] {
  opacity: 0;
  transform: translateY(18px);
  transition: opacity var(--duration-slow) var(--ease-out),
    transform var(--duration-slow) var(--ease-entrance);
  transition-delay: var(--reveal-delay, 0ms);
  will-change: opacity, transform;
}

[data-reveal][data-revealed] {
  opacity: 1;
  transform: none;
  /* Release the compositor hint once the entrance has played to keep
     scrolling and subsequent interactions smooth. */
  will-change: auto;
}

[data-reveal-variant="left"] {
  transform: translateX(-22px);
}

[data-reveal-variant="right"] {
  transform: translateX(22px);
}

[data-reveal-variant="scale"] {
  transform: scale(0.97);
}

/* ==========================================================================
   Interaction feedback — subtle lift on content cards and tactile press.
   ========================================================================== */

.card,
.topic-card,
.focus-card {
  transition: transform var(--duration-medium) var(--ease-emphasized),
    box-shadow var(--duration-medium) var(--ease-standard),
    border-color var(--duration-fast) var(--ease-standard);
}

.card:hover,
.topic-card:hover,
.focus-card:hover {
  transform: translateY(-4px);
  box-shadow: var(--shadow-md);
  border-color: var(--border-strong);
}

.btn:active {
  transform: translateY(0) scale(0.985);
}

/* ==========================================================================
   Loading & content-swap — shared skeleton primitives and a graceful fade
   for async content so the UI feels fluid while data resolves.
   ========================================================================== */

.skeleton {
  display: block;
  position: relative;
  color: transparent !important;
  border-radius: var(--radius-sm, 6px);
  background: linear-gradient(
    100deg,
    var(--bg-inset, rgba(17, 42, 67, 0.06)) 30%,
    var(--bg-elevated, rgba(17, 42, 67, 0.12)) 50%,
    var(--bg-inset, rgba(17, 42, 67, 0.06)) 70%
  );
  background-size: 200% 100%;
  animation: skeletonShimmer 1.4s var(--ease-standard) infinite;
}

@keyframes skeletonShimmer {
  0% {
    background-position: 200% 0;
  }
  100% {
    background-position: -200% 0;
  }
}

/* Containers that fade their freshly-loaded content into place. */
[data-loaded="false"] {
  opacity: 0.999; /* establishes a paint layer without hiding skeletons */
}

.is-content-enter {
  animation: ds-content-enter var(--duration-medium) var(--ease-out) both;
}

@keyframes ds-content-enter {
  from {
    opacity: 0;
  }
  to {
    opacity: 1;
  }
}

@media (prefers-reduced-motion: reduce) {
  .skeleton {
    animation: none;
  }

  .is-content-enter {
    animation: none;
  }
}

@media (prefers-reduced-motion: reduce) {
  html {
    scroll-behavior: auto;
  }

  *,
  *::before,
  *::after {
    animation-duration: 0.01ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.01ms !important;
    scroll-behavior: auto !important;
  }

  .u-animate-fade-up {
    opacity: 1;
    transform: none;
  }

  [data-reveal] {
    opacity: 1;
    transform: none;
    transition: none;
  }

  .card:hover,
  .topic-card:hover,
  .focus-card:hover,
  .btn:active {
    transform: none;
  }
}

/* ==========================================================================
   Site footer — a considered, credibility-reinforcing close to every page.
   Brand statement, secondary navigation, availability cue, and a legal bar.
   ========================================================================== */

.site-footer {
  margin-top: var(--space-11);
  border-top: var(--border-hairline) solid var(--border-soft);
  background: var(--bg-inset);
  color: var(--text-secondary);
}

.site-footer__inner {
  display: grid;
  grid-template-columns: minmax(0, 1.4fr) minmax(0, 1fr);
  gap: clamp(2rem, 5vw, 4.5rem);
  padding-block: var(--space-9) var(--space-8);
}

.site-footer__brand-link {
  display: inline-flex;
  align-items: center;
  gap: 0.6rem;
  text-decoration: none;
  color: var(--text-primary);
}

.site-footer__brand-mark {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 5.25rem;
  /* height: 2.25rem; */
  border-radius: var(--radius-sm);
  overflow: hidden;
}

.site-footer__brand-mark img {
  display: block;
  width: 100%;
  height: 100%;
  object-fit: cover;
}

.site-footer__brand-name {
  font-family: var(--font-display);
  font-weight: var(--weight-semibold);
  font-size: var(--fs-400);
  color: var(--text-primary);
}

.site-footer__tagline {
  margin: var(--space-4) 0 0;
  max-width: 42ch;
  font-size: var(--fs-300);
  line-height: var(--line-height-body);
  color: var(--text-muted);
  text-wrap: pretty;
}

.site-footer__status {
  display: inline-flex;
  align-items: center;
  gap: 0.55rem;
  margin: var(--space-5) 0 0;
  font-size: var(--fs-200);
  font-weight: var(--weight-medium);
  color: var(--text-secondary);
}

.site-footer__status-dot {
  width: 0.55rem;
  height: 0.55rem;
  border-radius: var(--radius-pill);
  background: var(--color-success);
  box-shadow: 0 0 0 4px var(--color-success-soft);
}

.site-footer__nav {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: clamp(1.5rem, 4vw, 3rem);
}

.site-footer__heading {
  margin: 0 0 var(--space-4);
  font-family: var(--font-body);
  font-size: var(--fs-100);
  font-weight: var(--weight-semibold);
  letter-spacing: var(--tracking-caps);
  text-transform: uppercase;
  color: var(--text-muted);
}

.site-footer__col ul {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  gap: var(--space-3);
}

.site-footer__col a {
  display: inline-block;
  color: var(--text-secondary);
  text-decoration: none;
  font-size: var(--fs-300);
  transition: color var(--duration-fast) var(--ease-standard);
}

.site-footer__col a:hover,
.site-footer__col a:focus-visible {
  color: var(--accent);
}

.site-footer__bar {
  border-top: var(--border-hairline) solid var(--border-soft);
}

.site-footer__bar-inner {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: space-between;
  gap: var(--space-4);
  padding-block: var(--space-5);
}

.site-footer__copy {
  margin: 0;
  font-size: var(--fs-200);
  color: var(--text-muted);
}

.site-footer__top {
  display: inline-flex;
  align-items: center;
  gap: 0.4rem;
  font-size: var(--fs-200);
  font-weight: var(--weight-medium);
  color: var(--text-secondary);
  text-decoration: none;
  transition: color var(--duration-fast) var(--ease-standard);
}

.site-footer__top svg {
  width: 1rem;
  height: 1rem;
}

.site-footer__top:hover,
.site-footer__top:focus-visible {
  color: var(--accent);
}

@media (max-width: 760px) {
  .site-footer__inner {
    grid-template-columns: 1fr;
    gap: var(--space-8);
    padding-block: var(--space-8) var(--space-7);
  }
}

@media (max-width: 480px) {
  .site-footer__nav {
    grid-template-columns: 1fr;
    gap: var(--space-7);
  }

  .site-footer__bar-inner {
    flex-direction: column;
    align-items: flex-start;
  }
}