/* ==========================================================================
   frame.css
   Base, design tokens, typography and page layout
   ========================================================================== */

/* ---------- Design tokens: dark theme (default) ---------- */
:root {
  color-scheme: dark;

  --font-sans: "Lato", "Segoe UI", Roboto, Helvetica, Arial, sans-serif;

  --color-bg: #1f1f1f;
  --color-bg-alt: #242424;
  --color-surface: #2a2a2a;
  --color-surface-2: #303030;
  --color-surface-hover: #333333;
  --color-text: #eaeaea;
  --color-text-muted: #b8b8b8;
  --color-heading: #ffffff;
  --color-accent: #4dabf7;
  --color-accent-strong: #2196f3;
  --color-accent-soft: rgba(77, 171, 247, 0.14);
  --color-border: rgba(255, 255, 255, 0.11);
  --color-border-strong: rgba(77, 171, 247, 0.45);
  --color-focus: #74c0fc;

  --shadow-sm: 0 4px 14px rgba(0, 0, 0, 0.18);
  --shadow-md: 0 10px 28px rgba(0, 0, 0, 0.24);
  --shadow-lg: 0 20px 52px rgba(0, 0, 0, 0.32);

  --radius-sm: 0.5rem;
  --radius-md: 0.8rem;
  --radius-lg: 1.1rem;
  --radius-pill: 999px;

  --header-height: 4.75rem;
  --page-width: 74rem;
  --content-width: 67rem;

  --space-1: 0.35rem;
  --space-2: 0.65rem;
  --space-3: 1rem;
  --space-4: 1.5rem;
  --space-5: 2rem;
  --space-6: 3rem;
  --space-7: 4.5rem;

  --transition-fast: 160ms ease;
  --transition-base: 260ms ease;
}

/* ---------- Light theme ---------- */
html[data-theme="light"] {
  color-scheme: light;

  --color-bg: #f4f6f8;
  --color-bg-alt: #eef1f4;
  --color-surface: #ffffff;
  --color-surface-2: #f7f9fb;
  --color-surface-hover: #f2f7fb;
  --color-text: #29323b;
  --color-text-muted: #5f6b76;
  --color-heading: #17212b;
  --color-accent: #1976d2;
  --color-accent-strong: #0d5eaf;
  --color-accent-soft: rgba(25, 118, 210, 0.11);
  --color-border: rgba(23, 33, 43, 0.12);
  --color-border-strong: rgba(25, 118, 210, 0.38);
  --color-focus: #0d6efd;

  --shadow-sm: 0 4px 14px rgba(31, 45, 61, 0.08);
  --shadow-md: 0 12px 30px rgba(31, 45, 61, 0.12);
  --shadow-lg: 0 22px 55px rgba(31, 45, 61, 0.16);
}

/* Compatibility while the old body.light-mode script is being removed. */
body.light-mode {
  --color-bg: #f4f6f8;
  --color-bg-alt: #eef1f4;
  --color-surface: #ffffff;
  --color-surface-2: #f7f9fb;
  --color-surface-hover: #f2f7fb;
  --color-text: #29323b;
  --color-text-muted: #5f6b76;
  --color-heading: #17212b;
  --color-accent: #1976d2;
  --color-accent-strong: #0d5eaf;
  --color-accent-soft: rgba(25, 118, 210, 0.11);
  --color-border: rgba(23, 33, 43, 0.12);
  --color-border-strong: rgba(25, 118, 210, 0.38);
  --color-focus: #0d6efd;
}

/* ---------- Reset and global behavior ---------- */
*,
*::before,
*::after {
  box-sizing: border-box;
}

html {
  min-width: 20rem;
  scroll-behavior: smooth;
  scroll-padding-top: calc(var(--header-height) + 1rem);
  background: var(--color-bg);
}

body {
  min-height: 100vh;
  margin: 0;
  padding-top: var(--header-height);
  overflow-x: hidden;
  font-family: var(--font-sans);
  font-size: 1rem;
  line-height: 1.7;
  color: var(--color-text);
  background:
    radial-gradient(circle at 85% 0%, var(--color-accent-soft), transparent 24rem),
    linear-gradient(180deg, var(--color-bg), var(--color-bg-alt));
  text-rendering: optimizeLegibility;
  -webkit-font-smoothing: antialiased;
  transition:
    color var(--transition-base),
    background-color var(--transition-base);
}

main {
  display: block;
}

header,
main,
footer {
  width: 100%;
}

section[id] {
  scroll-margin-top: calc(var(--header-height) + 1rem);
}

/* ---------- Typography ---------- */
h1,
h2,
h3,
h4,
h5,
h6 {
  margin: 0 0 0.75em;
  color: var(--color-heading);
  font-weight: 700;
  line-height: 1.24;
  text-wrap: balance;
}

h1 {
  font-size: clamp(2.15rem, 5vw, 4rem);
  letter-spacing: -0.035em;
}

h2 {
  font-size: clamp(1.75rem, 3.2vw, 2.45rem);
  letter-spacing: -0.025em;
}

h3 {
  font-size: clamp(1.25rem, 2.2vw, 1.62rem);
}

h4 {
  font-size: 1.15rem;
}

h5,
h6 {
  font-size: 1rem;
}

p,
ul,
ol,
dl,
blockquote {
  margin-top: 0;
  margin-bottom: 1rem;
}

p {
  color: var(--color-text);
}

strong {
  color: var(--color-heading);
  font-weight: 700;
}

small,
.date,
.institution,
.authors,
.thesis-info {
  color: var(--color-text-muted);
}

a {
  color: var(--color-accent);
  text-decoration: none;
  text-underline-offset: 0.2em;
  transition: color var(--transition-fast);
}

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

a:not([class]):hover {
  text-decoration: underline;
}

hr {
  width: 100%;
  height: 1px;
  margin: 0 0 var(--space-4);
  border: 0;
  background: linear-gradient(
    90deg,
    var(--color-accent),
    var(--color-border) 45%,
    transparent
  );
  opacity: 0.75;
}

ul,
ol {
  padding-left: 1.35rem;
}

li + li {
  margin-top: 0.4rem;
}

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

img {
  height: auto;
}

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

/* ---------- Shared layout ---------- */
.content-container {
  width: min(calc(100% - 2rem), var(--page-width));
  margin: 1.35rem auto;
  padding: clamp(1.25rem, 3vw, 2.35rem);
  color: var(--color-text);
  background: color-mix(in srgb, var(--color-surface) 96%, transparent);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
  box-shadow: var(--shadow-sm);
  transition:
    border-color var(--transition-base),
    box-shadow var(--transition-base),
    background-color var(--transition-base);
}

.content-container:hover {
  border-color: var(--color-border-strong);
  box-shadow: var(--shadow-md);
}

.content {
  width: min(100%, var(--content-width));
  margin-inline: auto;
}

.content > :last-child {
  margin-bottom: 0;
}

.section-intro {
  max-width: 52rem;
  color: var(--color-text-muted);
  font-size: 1.05rem;
}

.surface {
  background: var(--color-surface-2);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
}

.card {
  min-width: 0;
  padding: 1.25rem;
  background: var(--color-surface-2);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  box-shadow: var(--shadow-sm);
  transition:
    transform var(--transition-base),
    border-color var(--transition-base),
    box-shadow var(--transition-base),
    background-color var(--transition-base);
}

.card:hover {
  transform: translateY(-0.2rem);
  border-color: var(--color-border-strong);
  box-shadow: var(--shadow-md);
  background: var(--color-surface-hover);
}

.grid {
  display: grid;
  grid-template-columns: repeat(12, minmax(0, 1fr));
  gap: 1rem;
}

/* ---------- Utility classes ---------- */
.visually-hidden {
  position: absolute !important;
  width: 1px !important;
  height: 1px !important;
  padding: 0 !important;
  margin: -1px !important;
  overflow: hidden !important;
  clip: rect(0, 0, 0, 0) !important;
  white-space: nowrap !important;
  border: 0 !important;
}

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

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

.no-scroll {
  overflow: hidden;
}

/* ---------- Responsive base ---------- */
@media (max-width: 64rem) {
  :root {
    --header-height: 4.5rem;
  }

  .content-container {
    width: min(calc(100% - 1.5rem), var(--page-width));
  }
}

@media (max-width: 40rem) {
  body {
    line-height: 1.65;
  }

  .content-container {
    width: calc(100% - 1rem);
    margin-block: 0.75rem;
    padding: 1.1rem;
    border-radius: var(--radius-md);
  }

  ul,
  ol {
    padding-left: 1.15rem;
  }
}

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

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