/* ==========================================================================
   global.css
   Design tokens (Material Design 3 inspired), reset, typography,
   theme tokens and shared components: header, navigation, buttons, footer.
   Font: Arial only. Breakpoints: 600px and 1024px (mobile-first).
   ========================================================================== */

/* --------------------------------------------------------------------------
   1. Tokens that do not depend on the theme
   -------------------------------------------------------------------------- */
:root {
  color-scheme: light;

  /* Brand colour (identical in both themes) */
  --md-primary: #7643e4;
  --md-on-primary: #ffffff;           /* contrast on primary: 5.7:1 (AA) */
  --md-primary-hover: #683bc9;        /* primary mixed with 12% black */

  /* Shape scale */
  --md-shape-sm: 0.5rem;
  --md-shape-md: 0.75rem;
  --md-shape-lg: 1.25rem;
  --md-shape-full: 999px;

  /* Elevation (shadow part; the tint comes from the surface colours) */
  --md-elev-1: 0 1px 2px rgb(0 0 0 / 0.3), 0 1px 3px 1px rgb(0 0 0 / 0.15);
  --md-elev-2: 0 1px 2px rgb(0 0 0 / 0.3), 0 2px 6px 2px rgb(0 0 0 / 0.15);
  --md-elev-3: 0 4px 8px 3px rgb(0 0 0 / 0.15), 0 1px 3px rgb(0 0 0 / 0.3);

  /* Surface glass effect: 0.9 opacity + 20px blur (see components) */
  --md-surface-alpha: 0.9;
  --md-blur: 20px;

  /* State layers derived from the primary colour */
  --md-state-hover: rgb(118 67 228 / 0.12);

  /* Layout */
  --header-h: 4rem;
  --gutter: clamp(1rem, 4vw, 2rem);
  --container-max: 72rem;

  /* M3 type scale (fluid where it matters) */
  --md-display: clamp(2.25rem, 1.5rem + 3.6vw, 3.5rem);
  --md-headline: clamp(1.5rem, 1.2rem + 1.4vw, 2rem);
  --md-title-lg: clamp(1.125rem, 1.05rem + 0.4vw, 1.375rem);
  --md-title-md: 1rem;
  --md-body-lg: 1rem;
  --md-body-md: 0.9375rem;
  --md-label-lg: 0.9375rem;
  --md-label-md: 0.8125rem;
}

/* --------------------------------------------------------------------------
   2. Theme tokens
   Light is the base. The dark block overrides colour roles only.
   -------------------------------------------------------------------------- */
:root,
:root[data-theme="light"] {
  color-scheme: light;

  --md-bg: #f2f2f2;                    /* main background */
  --md-secondary: #c0c0c0;             /* secondary surfaces, borders, outlines */
  --md-surface-rgb: 236 233 241;       /* #f2f2f2 with a 5% primary tint */
  --md-on-surface: #121212;
  --md-on-surface-variant: #3d3d3d;
  --md-outline: #c0c0c0;
  --md-outline-strong: #767676;        /* form controls: >= 3:1 non-text contrast */

  --md-primary-text: #4f26b0;          /* primary as text/focus ring on light: >= 4.9:1 */
  --md-primary-container: #d9cfef;
  --md-on-primary-container: #2a0f66;
  --md-secondary-container: #c0c0c0;
  --md-on-secondary-container: #121212;

  --md-glow: rgb(118 67 228 / 0.28);   /* gradient behind the glass surfaces */
  --md-disabled-bg: rgb(18 18 18 / 0.12);
  --md-disabled-fg: rgb(18 18 18 / 0.38);
}

:root[data-theme="dark"] {
  color-scheme: dark;

  --md-bg: #0c0c0c;
  --md-secondary: #2f2f2f;
  --md-surface-rgb: 30 28 38;          /* #2f2f2f/#0c0c0c blend with a primary tint */
  --md-on-surface: #f2f2f2;
  --md-on-surface-variant: #c0c0c0;
  --md-outline: #2f2f2f;
  --md-outline-strong: #8a8a8a;

  --md-primary-text: #b498f0;          /* primary mixed with 45% white: 8:1 on #0c0c0c */
  --md-primary-container: #41345c;
  --md-on-primary-container: #e6dcfc;
  --md-secondary-container: #2f2f2f;
  --md-on-secondary-container: #f2f2f2;

  --md-primary-hover: #8152e6;         /* primary mixed with 8% white (white text 4.9:1) */
  --md-glow: rgb(118 67 228 / 0.34);
  --md-disabled-bg: rgb(242 242 242 / 0.12);
  --md-disabled-fg: rgb(242 242 242 / 0.38);
}

/* --------------------------------------------------------------------------
   3. Reset and base typography
   -------------------------------------------------------------------------- */
*,
*::before,
*::after {
  box-sizing: border-box;
}

html {
  -webkit-text-size-adjust: 100%;
  text-size-adjust: 100%;
  scroll-padding-top: calc(var(--header-h) + 1rem);
}

@media (prefers-reduced-motion: no-preference) {
  html {
    scroll-behavior: smooth;
  }
}

body {
  margin: 0;
  min-height: 100vh;
  min-height: 100dvh;
  display: flex;
  flex-direction: column;
  font-family: Arial, sans-serif;
  font-size: var(--md-body-lg);
  line-height: 1.5;
  color: var(--md-on-surface);
  background-color: var(--md-bg);
}

/* Soft gradient behind every page so the glass blur is visible */
body::before {
  content: "";
  position: fixed;
  inset: 0;
  z-index: -1;
  pointer-events: none;
  background:
    radial-gradient(40rem circle at 10% 0%, var(--md-glow), transparent 60%),
    radial-gradient(36rem circle at 100% 35%, var(--md-glow), transparent 60%),
    radial-gradient(44rem circle at 20% 100%, var(--md-glow), transparent 60%);
}

main {
  flex: 1 0 auto;
}

main:focus {
  outline: none;
}

h1,
h2,
h3,
h4,
p,
ul,
ol,
dl,
dd,
figure {
  margin: 0;
}

h1,
h2,
h3,
h4 {
  font-family: inherit;
  font-weight: 700;
  line-height: 1.2;
}

h1 {
  font-size: var(--md-display);
  line-height: 1.1;
  letter-spacing: -0.01em;
}

h2 {
  font-size: var(--md-headline);
  line-height: 1.25;
}

h3 {
  font-size: var(--md-title-lg);
  line-height: 1.3;
}

h4 {
  font-size: var(--md-title-md);
}

ul[role="list"],
.list-reset {
  list-style: none;
  padding: 0;
}

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

a {
  color: var(--md-primary-text);
  text-underline-offset: 0.2em;
}

a:hover {
  text-decoration-thickness: 2px;
}

button,
input,
select,
textarea {
  font: inherit;
  color: inherit;
}

button {
  cursor: pointer;
}

/* Visible focus for every interactive element */
:focus-visible {
  outline: 3px solid var(--md-primary-text);
  outline-offset: 3px;
}

/* --------------------------------------------------------------------------
   4. Utilities
   -------------------------------------------------------------------------- */
.container {
  width: min(100% - 2 * var(--gutter), var(--container-max));
  margin-inline: auto;
}

.visually-hidden {
  position: absolute;
  width: 1px;
  height: 1px;
  margin: -1px;
  padding: 0;
  overflow: hidden;
  clip: rect(0 0 0 0);
  clip-path: inset(50%);
  white-space: nowrap;
  border: 0;
}

.skip-link {
  position: absolute;
  top: -4rem;
  left: 0.75rem;
  z-index: 1000;
  padding: 0.75rem 1.25rem;
  border-radius: var(--md-shape-full);
  background: var(--md-primary);
  color: var(--md-on-primary);
  font-weight: 700;
  text-decoration: none;
}

.skip-link:focus {
  top: 0.75rem;
}

/* --------------------------------------------------------------------------
   5. Buttons (M3: filled, tonal, outlined, text)
   -------------------------------------------------------------------------- */
.button {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 0.5rem;
  min-height: 3rem;
  padding: 0.5rem 1.5rem;
  border: 1px solid transparent;
  border-radius: var(--md-shape-full);
  font-size: var(--md-label-lg);
  font-weight: 700;
  line-height: 1.2;
  text-align: center;
  text-decoration: none;
  transition: background-color 0.2s ease, box-shadow 0.2s ease;
}

.button--filled {
  background: var(--md-primary);
  color: var(--md-on-primary);
}

.button--filled:hover {
  background: var(--md-primary-hover);
  box-shadow: var(--md-elev-1);
  text-decoration: none;
}

.button--tonal {
  background: var(--md-primary-container);
  color: var(--md-on-primary-container);
}

.button--tonal:hover {
  box-shadow: var(--md-elev-1);
  text-decoration: none;
}

.button--outlined {
  border-color: var(--md-outline-strong);
  color: var(--md-primary-text);
}

.button--outlined:hover {
  background: var(--md-state-hover);
  text-decoration: none;
}

.button--text {
  min-height: 2.75rem;
  padding-inline: 0.75rem;
  color: var(--md-primary-text);
}

.button--text:hover {
  background: var(--md-state-hover);
  text-decoration: none;
}

.button:disabled,
.button[aria-disabled="true"] {
  background: var(--md-disabled-bg);
  color: var(--md-disabled-fg);
  box-shadow: none;
  cursor: not-allowed;
}

/* --------------------------------------------------------------------------
   6. Header and navigation
   The glass layer is a pseudo-element so the fixed drawer (a descendant of
   the header) is not trapped inside a backdrop-filter containing block.
   -------------------------------------------------------------------------- */
.site-header {
  position: sticky;
  top: 0;
  z-index: 100;
  isolation: isolate;
}

.site-header::before {
  content: "";
  position: absolute;
  inset: 0;
  z-index: -1;
  background: rgb(var(--md-surface-rgb) / var(--md-surface-alpha));
  -webkit-backdrop-filter: blur(var(--md-blur));
  backdrop-filter: blur(var(--md-blur));
  border-bottom: 1px solid var(--md-outline);
}

.site-header__inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1rem;
  min-height: var(--header-h);
}

/* Brand */
.brand {
  display: inline-flex;
  align-items: center;
  gap: 0.625rem;
  min-height: 3rem;
  color: var(--md-on-surface);
  font-size: 1.125rem;
  font-weight: 700;
  text-decoration: none;
}

.brand:hover {
  text-decoration: none;
}

.brand__logo {
  width: 2.25rem;
  height: 2.25rem;
  border-radius: 0.625rem;
}

/* Hamburger button (< 1024px) */
.nav-toggle {
  position: relative;
  flex: none;
  width: 3rem;
  height: 3rem;
  padding: 0;
  border: 0;
  border-radius: var(--md-shape-full);
  background: transparent;
  color: var(--md-on-surface);
}

.nav-toggle:hover {
  background: var(--md-state-hover);
}

.nav-toggle__bar {
  position: absolute;
  left: 0.75rem;
  width: 1.5rem;
  height: 2px;
  border-radius: 2px;
  background: currentColor;
  transition: transform 0.25s ease, opacity 0.2s ease;
}

.nav-toggle__bar:nth-child(1) {
  top: 1.0625rem;
}

.nav-toggle__bar:nth-child(2) {
  top: 1.4375rem;
}

.nav-toggle__bar:nth-child(3) {
  top: 1.8125rem;
}

.nav-toggle[aria-expanded="true"] .nav-toggle__bar:nth-child(1) {
  transform: translateY(0.375rem) rotate(45deg);
}

.nav-toggle[aria-expanded="true"] .nav-toggle__bar:nth-child(2) {
  opacity: 0;
}

.nav-toggle[aria-expanded="true"] .nav-toggle__bar:nth-child(3) {
  transform: translateY(-0.375rem) rotate(-45deg);
}

/* Drawer (mobile): slides in from the right under the header */
.site-nav {
  position: fixed;
  top: var(--header-h);
  right: 0;
  bottom: 0;
  width: min(20rem, 85vw);
  padding: 1rem;
  overflow-y: auto;
  background: rgb(var(--md-surface-rgb) / var(--md-surface-alpha));
  -webkit-backdrop-filter: blur(var(--md-blur));
  backdrop-filter: blur(var(--md-blur));
  border-inline-start: 1px solid var(--md-outline);
  box-shadow: var(--md-elev-3);
  transform: translateX(100%);
  visibility: hidden;
  transition: transform 0.25s ease, visibility 0s linear 0.25s;
}

.site-nav.is-open {
  transform: none;
  visibility: visible;
  transition: transform 0.25s ease, visibility 0s;
}

.site-nav__list {
  display: flex;
  flex-direction: column;
  gap: 0.25rem;
  margin: 0;
  padding: 0;
  list-style: none;
}

.site-nav__link {
  display: flex;
  align-items: center;
  min-height: 3rem;
  padding: 0 1.25rem;
  border-radius: var(--md-shape-full);
  color: var(--md-on-surface);
  font-size: var(--md-label-lg);
  font-weight: 700;
  text-decoration: none;
}

.site-nav__link:hover {
  background: var(--md-state-hover);
  text-decoration: none;
}

.site-nav__link[aria-current="page"] {
  background: var(--md-primary-container);
  color: var(--md-on-primary-container);
}

.site-nav__tools {
  margin-top: 0.75rem;
  padding-top: 0.75rem;
  border-top: 1px solid var(--md-outline);
}

/* Theme toggle: shows a moon in light mode, a sun in dark mode */
.theme-toggle {
  display: flex;
  align-items: center;
  gap: 0.75rem;
  width: 100%;
  min-height: 3rem;
  padding: 0 1.25rem;
  border: 1px solid var(--md-outline-strong);
  border-radius: var(--md-shape-full);
  background: transparent;
  color: var(--md-on-surface);
  font-size: var(--md-label-lg);
  font-weight: 700;
}

.theme-toggle:hover {
  background: var(--md-state-hover);
}

.theme-toggle__icon {
  flex: none;
  width: 1.5rem;
  height: 1.5rem;
  fill: none;
  stroke: currentColor;
  stroke-width: 2;
  stroke-linecap: round;
  stroke-linejoin: round;
}

.theme-toggle__icon--sun,
:root[data-theme="dark"] .theme-toggle__icon--moon {
  display: none;
}

:root[data-theme="dark"] .theme-toggle__icon--sun {
  display: block;
}

/* Desktop (>= 1024px): horizontal top bar, no hamburger */
@media (min-width: 1024px) {
  .nav-toggle {
    display: none;
  }

  .site-nav {
    position: static;
    width: auto;
    margin-inline-start: auto;
    padding: 0;
    overflow: visible;
    background: none;
    -webkit-backdrop-filter: none;
    backdrop-filter: none;
    border: 0;
    box-shadow: none;
    transform: none;
    visibility: visible;
    transition: none;
  }

  .site-nav__list {
    flex-direction: row;
    align-items: center;
    gap: 0.25rem;
  }

  .site-nav__tools {
    margin: 0 0 0 0.5rem;
    padding: 0;
    border: 0;
  }

  .theme-toggle {
    justify-content: center;
    width: 3rem;
    padding: 0;
  }

  /* Label stays available to screen readers */
  .theme-toggle__label {
    position: absolute;
    width: 1px;
    height: 1px;
    margin: -1px;
    overflow: hidden;
    clip: rect(0 0 0 0);
    clip-path: inset(50%);
    white-space: nowrap;
  }
}

/* --------------------------------------------------------------------------
   7. Footer
   -------------------------------------------------------------------------- */
.site-footer {
  margin-top: clamp(2rem, 5vw, 4rem);
  background: rgb(var(--md-surface-rgb) / var(--md-surface-alpha));
  -webkit-backdrop-filter: blur(var(--md-blur));
  backdrop-filter: blur(var(--md-blur));
  border-top: 1px solid var(--md-outline);
  color: var(--md-on-surface-variant);
  font-size: var(--md-body-md);
}

.site-footer__inner {
  display: grid;
  gap: 2rem;
  padding-block: 2.5rem 1.5rem;
}

.site-footer__brand {
  margin-bottom: 0.5rem;
  color: var(--md-on-surface);
  font-size: 1.125rem;
  font-weight: 700;
}

.site-footer__title {
  margin-bottom: 0.5rem;
  color: var(--md-on-surface);
  font-size: var(--md-title-md);
}

.site-footer__list {
  display: grid;
  gap: 0.125rem;
  margin: 0;
  padding: 0;
  list-style: none;
}

.site-footer__list a {
  display: inline-block;
  padding-block: 0.375rem;
  color: var(--md-on-surface-variant);
}

.site-footer__list a:hover {
  color: var(--md-primary-text);
}

.site-footer__legal {
  padding-block: 1rem 2rem;
  border-top: 1px solid var(--md-outline);
  font-size: var(--md-label-md);
}

@media (min-width: 600px) {
  .site-footer__inner {
    grid-template-columns: repeat(2, 1fr);
  }

  .site-footer__about {
    grid-column: 1 / -1;
  }
}

@media (min-width: 1024px) {
  .site-footer__inner {
    grid-template-columns: 1.5fr 1fr 1fr;
  }

  .site-footer__about {
    grid-column: auto;
  }
}

/* --------------------------------------------------------------------------
   8. Reduced motion
   -------------------------------------------------------------------------- */
@media (prefers-reduced-motion: reduce) {
  *,
  *::before,
  *::after {
    animation-duration: 0.01ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.01ms !important;
    transition-delay: 0s !important;
    scroll-behavior: auto !important;
  }
}