/* =========================================================
   Adamas Diamonds — Personal Blog
   Design System: Dark Glassmorphism (deep-space + frosted glass)
   Fonts: Playfair Display (display) / Inter (body)
   ========================================================= */

:root {
  /* brand gradient & glow */
  --brand-blue: #3b82f6;
  --brand-cyan: #22d3ee;
  --brand-indigo: #6366f1;
  --brand-grad: linear-gradient(110deg, #3b82f6 0%, #22d3ee 50%, #6366f1 100%);
  --brand-glow: 0 0 28px rgba(56, 189, 248, 0.4);

  /* dark base (default) */
  --color-background: #06070f;
  --color-foreground: #e7edf8;
  --color-secondary: #a6b4d0;
  --color-muted: #66758f;
  --color-accent: #38bdf8;
  --color-accent-soft: rgba(56, 189, 248, 0.16);

  --glass-bg: rgba(255, 255, 255, 0.07);
  --glass-bg-strong: rgba(255, 255, 255, 0.1);
  --glass-border: rgba(255, 255, 255, 0.12);
  --glass-border-strong: rgba(255, 255, 255, 0.24);
  --glass-blur: 18px;
  --glass-saturate: saturate(150%);
  --glass-shadow: 0 8px 32px rgba(0, 0, 0, 0.45);

  --font-display: 'Playfair Display', Georgia, 'Times New Roman', serif;
  --font-body: 'Inter', -apple-system, BlinkMacSystemFont, 'Helvetica Neue', Arial, sans-serif;

  --space-1: 0.25rem;
  --space-2: 0.5rem;
  --space-3: 0.75rem;
  --space-4: 1rem;
  --space-6: 1.5rem;
  --space-8: 2rem;
  --space-12: 3rem;
  --space-16: 4rem;
  --space-24: 6rem;

  --radius-sm: 10px;
  --radius-md: 16px;
  --radius-lg: 22px;
  --radius-xl: 28px;

  --ease-out: cubic-bezier(0.22, 1, 0.36, 1);
  --dur-fast: 150ms;
  --dur-base: 250ms;

  --container: 1120px;
  --gutter: clamp(1.25rem, 5vw, 2.5rem);
}

[data-theme='light'] {
  --color-background: #eef2fb;
  --color-foreground: #171e2e;
  --color-secondary: #4c5a75;
  --color-muted: #7b8aa3;
  --color-accent: #2563eb;
  --color-accent-soft: rgba(37, 99, 235, 0.14);

  --glass-bg: rgba(255, 255, 255, 0.55);
  --glass-bg-strong: rgba(255, 255, 255, 0.72);
  --glass-border: rgba(255, 255, 255, 0.75);
  --glass-border-strong: rgba(255, 255, 255, 0.95);
  --glass-shadow: 0 8px 30px rgba(90, 110, 160, 0.18);
}

/* ---------- Reset ---------- */

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

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

body {
  font-family: var(--font-body);
  font-size: 1rem;
  line-height: 1.7;
  color: var(--color-foreground);
  background-color: var(--color-background);
  min-height: 100dvh;
  display: flex;
  flex-direction: column;
  transition: color var(--dur-base) var(--ease-out);
  -webkit-font-smoothing: antialiased;
}

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

a {
  color: var(--color-accent);
  text-decoration: none;
  transition: color var(--dur-fast) var(--ease-out);
}

a:hover {
  color: var(--color-foreground);
}

a:focus-visible,
button:focus-visible,
input:focus-visible {
  outline: 2px solid var(--color-accent);
  outline-offset: 2px;
  border-radius: var(--radius-sm);
}

button {
  font-family: inherit;
  cursor: pointer;
}

ul,
ol {
  padding-left: 1.4em;
}

/* ---------- Deep-space background ---------- */

.bg {
  position: fixed;
  inset: 0;
  z-index: -1;
  background-color: #05060f;
  background-image:
    radial-gradient(1px 1px at 18% 32%, rgba(255, 255, 255, 0.7), transparent 100%),
    radial-gradient(1px 1px at 42% 18%, rgba(255, 255, 255, 0.55), transparent 100%),
    radial-gradient(1px 1px at 66% 40%, rgba(255, 255, 255, 0.5), transparent 100%),
    radial-gradient(1px 1px at 84% 22%, rgba(255, 255, 255, 0.6), transparent 100%),
    radial-gradient(1px 1px at 30% 70%, rgba(255, 255, 255, 0.4), transparent 100%),
    radial-gradient(1px 1px at 72% 78%, rgba(255, 255, 255, 0.45), transparent 100%),
    radial-gradient(1px 1px at 55% 88%, rgba(255, 255, 255, 0.5), transparent 100%),
    radial-gradient(1200px 800px at 12% -10%, rgba(59, 130, 246, 0.28), transparent 62%),
    radial-gradient(1000px 720px at 110% 12%, rgba(99, 102, 241, 0.26), transparent 56%),
    linear-gradient(135deg, rgba(0, 0, 0, 0.6) 0%, rgba(20, 10, 50, 0.85) 100%),
    url('https://img2.baidu.com/it/u=3345750435,2422073076&fm=253&fmt=auto&app=138&f=JPEG?w=889&h=500');
  background-size:
    auto, auto, auto, auto, auto, auto, auto,
    auto, auto, auto,
    cover;
  background-repeat: no-repeat;
  background-position: center;
}

[data-theme='light'] .bg {
  background-color: #eef2fb;
  background-image:
    radial-gradient(1200px 800px at 12% -10%, rgba(147, 197, 253, 0.5), transparent 62%),
    radial-gradient(1000px 720px at 110% 12%, rgba(196, 181, 253, 0.45), transparent 56%),
    radial-gradient(900px 620px at 50% 118%, rgba(165, 243, 252, 0.4), transparent 56%),
    linear-gradient(160deg, #eef2fb 0%, #e6ecfa 46%, #ede7fb 100%);
  background-size: auto;
  background-repeat: no-repeat;
  background-position: center;
}

/* ---------- Frosted glass helper ---------- */

.glass,
.bio,
.about-stack,
.article-body,
.article-nav,
.post-card,
.article-nav__link {
  background: var(--glass-bg);
  -webkit-backdrop-filter: blur(var(--glass-blur)) var(--glass-saturate);
  backdrop-filter: blur(var(--glass-blur)) var(--glass-saturate);
  border: 1px solid var(--glass-border);
  box-shadow: var(--glass-shadow);
}

/* ---------- Layout ---------- */

.container {
  width: 100%;
  max-width: var(--container);
  margin-inline: auto;
  padding-inline: var(--gutter);
}

main {
  flex: 1 0 auto;
}

.section {
  padding-block: var(--space-16);
}

.section--tight {
  padding-block: var(--space-8);
}

/* ---------- Header ---------- */

.site-header {
  position: sticky;
  top: 0;
  z-index: 50;
  background: var(--glass-bg);
  -webkit-backdrop-filter: blur(16px) var(--glass-saturate);
  backdrop-filter: blur(16px) var(--glass-saturate);
  border-bottom: 1px solid var(--glass-border);
}

.nav {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: var(--space-4);
  height: 4.25rem;
}

.brand {
  display: inline-flex;
  align-items: center;
  gap: var(--space-2);
  color: var(--color-foreground);
  font-family: var(--font-display);
  font-weight: 700;
  font-size: 1.25rem;
  letter-spacing: -0.02em;
}

.brand:hover {
  color: var(--color-foreground);
}

.brand__mark {
  width: 10px;
  height: 10px;
  background: var(--brand-grad);
  transform: rotate(45deg);
  border-radius: 2px;
  box-shadow: 0 0 12px rgba(56, 189, 248, 0.6);
}

.nav__list {
  display: flex;
  align-items: center;
  gap: var(--space-6);
  list-style: none;
  padding: 0;
}

.nav__link {
  position: relative;
  color: var(--color-secondary);
  font-size: 0.925rem;
  font-weight: 500;
  padding-block: var(--space-2);
}

.nav__link::after {
  content: '';
  position: absolute;
  left: 0;
  bottom: 0;
  width: 100%;
  height: 2px;
  border-radius: 999px;
  background: var(--brand-grad);
  transform: scaleX(0);
  transform-origin: left;
  transition: transform var(--dur-base) var(--ease-out);
}

.nav__link:hover {
  color: var(--color-foreground);
  text-shadow: var(--brand-glow);
}

.nav__link:hover::after,
.nav__link[aria-current='page']::after {
  transform: scaleX(1);
}

.nav__link[aria-current='page'] {
  color: var(--color-foreground);
}

.nav__actions {
  display: flex;
  align-items: center;
  gap: var(--space-2);
}

.theme-toggle,
.nav-toggle {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 2.5rem;
  height: 2.5rem;
  border: 1px solid var(--glass-border);
  border-radius: 50%;
  background: var(--glass-bg);
  color: var(--color-foreground);
  transition: border-color var(--dur-fast) var(--ease-out),
    box-shadow var(--dur-fast) var(--ease-out),
    color var(--dur-fast) var(--ease-out);
}

.theme-toggle:hover,
.nav-toggle:hover {
  border-color: var(--glass-border-strong);
  color: var(--color-accent);
  box-shadow: 0 0 16px rgba(56, 189, 248, 0.35);
}

.nav-toggle {
  display: none;
}

/* ---------- Hero ---------- */

.hero {
  position: relative;
  padding-block: clamp(4.5rem, 12vw, 8rem) clamp(3rem, 8vw, 5rem);
  overflow: hidden;
}

.hero__grid {
  display: grid;
  grid-template-columns: 1fr;
}

.hero__content {
  text-align: center;
}

.hero__eyebrow {
  display: inline-flex;
  align-items: center;
  gap: var(--space-3);
  font-size: 0.8rem;
  font-weight: 600;
  letter-spacing: 0.18em;
  text-transform: uppercase;
  color: var(--color-accent);
  margin-bottom: var(--space-6);
  text-shadow: var(--brand-glow);
}

.hero__eyebrow::before,
.hero__eyebrow::after {
  content: '';
  width: 2.5rem;
  height: 1px;
  background: var(--brand-grad);
}

.hero__title {
  font-family: var(--font-display);
  font-weight: 600;
  font-size: clamp(2.6rem, 7vw, 4.75rem);
  line-height: 1.08;
  letter-spacing: -0.02em;
  margin-bottom: var(--space-8);
  text-shadow: 0 0 44px rgba(56, 189, 248, 0.22);
}

.hero__brand-link {
  position: relative;
  display: inline-block;
  color: var(--color-foreground);
  text-decoration: none;
  transition: transform var(--dur-base) var(--ease-out),
    text-shadow var(--dur-base) var(--ease-out);
}

.hero__brand-link:hover {
  color: var(--color-foreground);
  transform: translateY(-0.4rem);
  text-shadow: var(--brand-glow);
}

.hero__brand-link::after {
  content: '';
  position: absolute;
  left: 0;
  right: 0;
  bottom: 0.02em;
  height: 3px;
  border-radius: 999px;
  background: var(--brand-grad);
  box-shadow: 0 0 12px rgba(56, 189, 248, 0.55);
  transform: scaleX(0);
  transform-origin: left;
  transition: transform var(--dur-base) var(--ease-out);
}

.hero__brand-link:hover::after {
  transform: scaleX(1);
}

.hero__brand-text {
  display: block;
  color: var(--color-foreground);
}

.hero__brand-gradient {
  position: absolute;
  inset: 0;
  background: var(--brand-grad);
  -webkit-background-clip: text;
  background-clip: text;
  -webkit-text-fill-color: transparent;
  color: transparent;
  opacity: 0;
  transition: opacity var(--dur-base) var(--ease-out);
}

.hero__brand-link:hover .hero__brand-gradient {
  opacity: 1;
}

.hero__lead {
  max-width: 34em;
  margin-inline: auto;
  font-size: 1.125rem;
  color: var(--color-secondary);
  line-height: 1.8;
}

/* ---------- Page hero (about) ---------- */

.page-hero {
  padding-block: var(--space-16) var(--space-8);
  text-align: center;
}

.page-hero__title {
  font-family: var(--font-display);
  font-size: clamp(2.2rem, 6vw, 3.4rem);
  font-weight: 600;
  letter-spacing: -0.02em;
  margin-bottom: var(--space-4);
  text-shadow: 0 0 36px rgba(56, 189, 248, 0.22);
}

.page-hero__lead {
  max-width: 42em;
  margin-inline: auto;
  font-size: 1.125rem;
  color: var(--color-secondary);
}

/* ---------- Bio (home) ---------- */

.bio {
  display: grid;
  grid-template-columns: auto 1fr auto;
  gap: var(--space-8);
  align-items: center;
  border-radius: var(--radius-xl);
  padding: clamp(1.5rem, 4vw, 2.5rem);
  transition: border-color var(--dur-base) var(--ease-out),
    box-shadow var(--dur-base) var(--ease-out);
}

.bio:hover {
  border-color: var(--glass-border-strong);
  box-shadow: 0 0 40px rgba(56, 189, 248, 0.18), var(--glass-shadow);
}

.bio__avatar {
  width: 5.5rem;
  height: 5.5rem;
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  background: var(--color-accent-soft);
  border: 1px solid var(--glass-border);
}

.bio__avatar .post-card__gem {
  width: 2.25rem;
  height: 2.25rem;
  border-width: 1.5px;
  border-color: var(--color-accent);
  box-shadow: 0 0 14px rgba(56, 189, 248, 0.5);
}

.bio__name {
  font-family: var(--font-display);
  font-size: 1.5rem;
  font-weight: 700;
  letter-spacing: -0.01em;
}

.bio__role {
  font-size: 0.875rem;
  color: var(--color-muted);
  margin-top: 0.15rem;
}

.bio__text {
  max-width: 52ch;
  color: var(--color-secondary);
}

.bio__cta {
  display: inline-flex;
  align-items: center;
  gap: var(--space-2);
  padding: 0.65rem 1.4rem;
  border: 1px solid var(--glass-border);
  border-radius: 999px;
  font-weight: 600;
  font-size: 0.9rem;
  color: var(--color-foreground);
  white-space: nowrap;
  transition: border-color var(--dur-fast) var(--ease-out),
    box-shadow var(--dur-fast) var(--ease-out),
    color var(--dur-fast) var(--ease-out);
}

.bio__cta:hover {
  border-color: var(--color-accent);
  box-shadow: 0 0 16px rgba(56, 189, 248, 0.4);
  color: var(--color-accent);
}

/* ---------- Cards (post-grid, kept for future lists) ---------- */

.post-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(320px, 1fr));
  gap: var(--space-8);
}

.post-card {
  display: flex;
  flex-direction: column;
  border-radius: var(--radius-lg);
  overflow: hidden;
  transition: transform var(--dur-base) var(--ease-out),
    box-shadow var(--dur-base) var(--ease-out),
    border-color var(--dur-base) var(--ease-out);
}

.post-card:hover {
  transform: translateY(-4px);
  border-color: var(--glass-border-strong);
  box-shadow: 0 0 40px rgba(56, 189, 248, 0.2), var(--glass-shadow);
}

.post-card__cover {
  aspect-ratio: 16 / 9;
  background:
    radial-gradient(circle at 30% 20%, var(--color-accent-soft), transparent 60%),
    linear-gradient(135deg, #0d1226, #05060f);
  display: flex;
  align-items: center;
  justify-content: center;
}

.post-card__gem {
  width: 3rem;
  height: 3rem;
  transform: rotate(45deg);
  border: 2px solid var(--color-accent);
  border-radius: 8px;
  opacity: 0.9;
  box-shadow: 0 0 18px rgba(56, 189, 248, 0.45);
}

.post-card__body {
  display: flex;
  flex-direction: column;
  gap: var(--space-3);
  padding: var(--space-6);
  flex: 1;
}

.post-card__meta {
  display: flex;
  align-items: center;
  gap: var(--space-3);
  font-size: 0.8rem;
  color: var(--color-muted);
}

.post-card__tag {
  display: inline-block;
  padding: 0.15em 0.7em;
  border-radius: 999px;
  background: var(--color-accent-soft);
  color: var(--color-accent);
  font-weight: 600;
  font-size: 0.72rem;
  letter-spacing: 0.06em;
  text-transform: uppercase;
}

.post-card__title {
  font-family: var(--font-display);
  font-size: 1.4rem;
  font-weight: 600;
  line-height: 1.3;
  letter-spacing: -0.01em;
}

.post-card__title a {
  color: var(--color-foreground);
}

.post-card__title a:hover {
  color: var(--color-accent);
}

.post-card__excerpt {
  font-size: 0.95rem;
  color: var(--color-secondary);
  flex: 1;
}

.post-card__footer {
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin-top: var(--space-2);
  font-size: 0.875rem;
}

.post-card__link {
  font-weight: 600;
}

/* ---------- About page ---------- */

.about-stack {
  display: grid;
  gap: var(--space-16);
  border-radius: var(--radius-xl);
  padding: clamp(1.5rem, 4vw, 3rem);
}

.about-block h2 {
  font-family: var(--font-display);
  font-size: 1.6rem;
  font-weight: 600;
  margin-bottom: var(--space-6);
  padding-bottom: var(--space-2);
  border-bottom: 1px solid var(--glass-border);
}

.about-block p {
  color: var(--color-secondary);
  max-width: 60ch;
  margin-bottom: var(--space-4);
}

.timeline {
  list-style: none;
  padding: 0;
  border-left: 1px solid var(--glass-border);
  margin-left: var(--space-2);
}

.timeline__item {
  position: relative;
  padding: 0 0 var(--space-6) var(--space-8);
}

.timeline__item::before {
  content: '';
  position: absolute;
  left: -5px;
  top: 0.5em;
  width: 9px;
  height: 9px;
  border-radius: 50%;
  background: var(--brand-grad);
  box-shadow: 0 0 10px rgba(56, 189, 248, 0.7);
}

.timeline__year {
  font-size: 0.78rem;
  font-weight: 600;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  color: var(--color-accent);
}

.timeline__title {
  font-weight: 600;
  margin: var(--space-1) 0 var(--space-1);
}

.timeline__desc {
  font-size: 0.95rem;
  color: var(--color-secondary);
}

.interests {
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-3);
}

.chip {
  display: inline-flex;
  align-items: center;
  padding: 0.5rem 1.1rem;
  border: 1px solid var(--glass-border);
  border-radius: 999px;
  font-size: 0.875rem;
  font-weight: 500;
  color: var(--color-secondary);
  background: var(--glass-bg);
  transition: border-color var(--dur-fast) var(--ease-out),
    color var(--dur-fast) var(--ease-out),
    box-shadow var(--dur-fast) var(--ease-out);
}

.chip:hover {
  border-color: var(--color-accent);
  color: var(--color-accent);
  box-shadow: 0 0 14px rgba(56, 189, 248, 0.35);
}

/* ---------- Article page ---------- */

.article-header {
  max-width: 46rem;
  margin-inline: auto;
  padding-block: var(--space-16) var(--space-8);
  text-align: center;
}

.article-header__meta {
  display: flex;
  justify-content: center;
  align-items: center;
  gap: var(--space-3);
  flex-wrap: wrap;
  margin-bottom: var(--space-6);
  font-size: 0.85rem;
  color: var(--color-muted);
}

.article-header__title {
  font-family: var(--font-display);
  font-size: clamp(1.9rem, 5vw, 3.2rem);
  font-weight: 600;
  line-height: 1.15;
  letter-spacing: -0.02em;
  margin-bottom: var(--space-6);
  text-shadow: 0 0 32px rgba(56, 189, 248, 0.2);
}

.article-header__excerpt {
  font-size: 1.125rem;
  color: var(--color-secondary);
  max-width: 38em;
  margin-inline: auto;
}

.article-body {
  max-width: 43rem;
  margin-inline: auto;
  padding: clamp(1.5rem, 4vw, 3rem);
  border-radius: var(--radius-xl);
  font-size: 1.0625rem;
  line-height: 1.85;
  color: var(--color-foreground);
  margin-bottom: var(--space-12);
}

.article-body h2 {
  font-family: var(--font-display);
  font-size: 1.7rem;
  font-weight: 600;
  letter-spacing: -0.01em;
  margin: var(--space-12) 0 var(--space-4);
  padding-bottom: var(--space-2);
  border-bottom: 1px solid var(--glass-border);
}

.article-body h3 {
  font-family: var(--font-display);
  font-size: 1.3rem;
  font-weight: 600;
  margin: var(--space-8) 0 var(--space-3);
}

.article-body p {
  margin-bottom: var(--space-6);
}

.article-body a {
  text-decoration: underline;
  text-underline-offset: 3px;
  text-decoration-thickness: 1px;
}

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

.article-body ul,
.article-body ol {
  margin-bottom: var(--space-6);
}

.article-body li {
  margin-bottom: var(--space-2);
}

.article-body blockquote {
  position: relative;
  margin: var(--space-8) 0;
  padding: var(--space-4) var(--space-6);
  font-family: var(--font-display);
  font-size: 1.25rem;
  font-style: italic;
  line-height: 1.6;
  color: var(--color-secondary);
  background: var(--glass-bg-strong);
  border: 1px solid var(--glass-border);
  border-radius: var(--radius-md);
  border-left: 3px solid var(--color-accent);
}

.article-body blockquote::before {
  content: '\201C';
  position: absolute;
  top: -0.4rem;
  left: 0.8rem;
  font-size: 3.5rem;
  color: var(--color-accent);
  line-height: 1;
  text-shadow: var(--brand-glow);
}

.article-body code {
  font-family: ui-monospace, SFMono-Regular, Menlo, Consolas, monospace;
  font-size: 0.875em;
  background: var(--glass-bg-strong);
  border: 1px solid var(--glass-border);
  border-radius: var(--radius-sm);
  padding: 0.1em 0.4em;
  color: var(--color-accent);
}

.article-body pre {
  background: rgba(3, 5, 12, 0.7);
  color: #cdd8ee;
  border: 1px solid var(--glass-border);
  border-radius: var(--radius-md);
  padding: var(--space-6);
  overflow-x: auto;
  margin-bottom: var(--space-6);
}

.article-body pre code {
  background: none;
  border: none;
  padding: 0;
  font-size: 0.875rem;
  line-height: 1.7;
  color: inherit;
}

.article-body hr {
  border: none;
  border-top: 1px solid var(--glass-border);
  margin: var(--space-12) 0;
}

.article-body .dropcap::first-letter {
  font-family: var(--font-display);
  float: left;
  font-size: 3.4em;
  line-height: 0.85;
  padding: 0.08em 0.12em 0 0;
  color: var(--color-accent);
  text-shadow: var(--brand-glow);
}

.article-nav {
  max-width: 43rem;
  margin-inline: auto;
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: var(--space-4);
  padding: var(--space-4);
  border-radius: var(--radius-lg);
}

.article-nav__link {
  display: flex;
  flex-direction: column;
  gap: var(--space-1);
  padding: var(--space-4) var(--space-6);
  border-radius: var(--radius-md);
  color: var(--color-foreground);
  transition: border-color var(--dur-fast) var(--ease-out),
    box-shadow var(--dur-fast) var(--ease-out);
}

.article-nav__link:hover {
  border-color: var(--glass-border-strong);
  box-shadow: 0 0 20px rgba(56, 189, 248, 0.22);
  color: var(--color-foreground);
}

.article-nav__label {
  font-size: 0.75rem;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  color: var(--color-muted);
}

.article-nav__title {
  font-family: var(--font-display);
  font-size: 1.05rem;
  font-weight: 600;
}

.article-nav__link--next {
  text-align: right;
}

/* ---------- Footer ---------- */

.site-footer {
  border-top: 1px solid var(--glass-border);
  background: var(--glass-bg);
  -webkit-backdrop-filter: blur(14px) var(--glass-saturate);
  backdrop-filter: blur(14px) var(--glass-saturate);
  padding-block: var(--space-8);
  margin-top: var(--space-8);
}

.footer__grid {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: space-between;
  gap: var(--space-4);
}

.footer__copyright {
  font-size: 0.85rem;
  color: var(--color-muted);
}

.footer__social {
  display: flex;
  align-items: center;
  gap: var(--space-4);
  list-style: none;
  padding: 0;
}

.footer__social a {
  color: var(--color-secondary);
  font-size: 0.85rem;
  font-weight: 500;
}

.footer__social a:hover {
  color: var(--color-accent);
  text-shadow: var(--brand-glow);
}

/* ---------- Back to top ---------- */

.to-top {
  position: fixed;
  right: var(--space-6);
  bottom: var(--space-6);
  z-index: 40;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: var(--space-2);
  padding: 0.7rem 1.3rem;
  border-radius: 999px;
  border: 1px solid var(--glass-border);
  background: var(--glass-bg-strong);
  -webkit-backdrop-filter: blur(var(--glass-blur)) var(--glass-saturate);
  backdrop-filter: blur(var(--glass-blur)) var(--glass-saturate);
  color: var(--color-foreground);
  font-size: 0.875rem;
  font-weight: 600;
  box-shadow: var(--glass-shadow);
  opacity: 0;
  visibility: hidden;
  transform: translateY(8px);
  transition: opacity var(--dur-base) var(--ease-out),
    transform var(--dur-base) var(--ease-out),
    visibility var(--dur-base) var(--ease-out),
    border-color var(--dur-fast) var(--ease-out),
    box-shadow var(--dur-fast) var(--ease-out);
}

.to-top.is-visible {
  opacity: 1;
  visibility: visible;
  transform: translateY(0);
}

.to-top:hover {
  border-color: var(--color-accent);
  color: var(--color-accent);
  box-shadow: 0 0 22px rgba(56, 189, 248, 0.4);
}

/* ---------- Reveal on scroll ---------- */

.reveal {
  opacity: 0;
  transform: translateY(16px);
  transition: opacity 0.6s var(--ease-out), transform 0.6s var(--ease-out);
}

.reveal.is-visible {
  opacity: 1;
  transform: translateY(0);
}

/* ---------- Portal (link-in-bio home) ---------- */

body.portal {
  min-height: 100dvh;
  display: flex;
  align-items: center;
  justify-content: center;
}

.portal__main {
  display: flex;
  flex-direction: column;
  align-items: center;
  text-align: center;
  gap: var(--space-6);
  padding: var(--space-8) var(--gutter);
  animation: portalFadeIn 1.1s var(--ease-out) both;
}

@keyframes portalFadeIn {
  from {
    opacity: 0;
    transform: translateY(20px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

.portal__title {
  display: flex;
  align-items: center;
  gap: var(--space-4);
}

.portal__avatar {
  width: 3.25rem;
  height: 3.25rem;
  background: var(--brand-grad);
  border-radius: 12px;
  transform: rotate(45deg);
  box-shadow: 0 0 26px rgba(56, 189, 248, 0.55);
  flex-shrink: 0;
}

.portal__name {
  font-family: var(--font-display);
  font-size: clamp(1.9rem, 6vw, 3.1rem);
  font-weight: 700;
  letter-spacing: -0.01em;
  line-height: 1.1;
  text-shadow: 0 0 40px rgba(56, 189, 248, 0.25);
}

.portal__bio {
  font-size: 0.95rem;
  font-weight: 400;
  letter-spacing: 0.22em;
  text-transform: uppercase;
  color: var(--color-secondary);
}

.portal__bio::before,
.portal__bio::after {
  content: '◆';
  color: var(--color-accent);
  margin: 0 0.75rem;
  font-size: 0.6rem;
  opacity: 0.7;
  vertical-align: middle;
}

.portal__actions {
  display: flex;
  flex-direction: column;
  gap: var(--space-3);
  width: min(100%, 20rem);
  margin-top: var(--space-4);
}

.portal__btn {
  display: flex;
  align-items: center;
  gap: var(--space-3);
  padding: 0.85rem 1.25rem;
  border-radius: 999px;
  border: 1px solid var(--glass-border);
  background: var(--glass-bg-strong);
  -webkit-backdrop-filter: blur(16px) var(--glass-saturate);
  backdrop-filter: blur(16px) var(--glass-saturate);
  color: var(--color-foreground);
  font-size: 0.95rem;
  font-weight: 500;
  box-shadow: var(--glass-shadow);
  transition: transform var(--dur-base) var(--ease-out),
    border-color var(--dur-base) var(--ease-out),
    box-shadow var(--dur-base) var(--ease-out),
    color var(--dur-base) var(--ease-out);
}

.portal__btn svg {
  width: 20px;
  height: 20px;
  flex-shrink: 0;
  color: var(--color-accent);
  transition: color var(--dur-base) var(--ease-out);
}

.portal__btn:hover {
  transform: translateY(-2px);
  border-color: var(--color-accent);
  box-shadow: 0 0 24px rgba(56, 189, 248, 0.35);
  color: var(--color-accent);
}

.friends {
  width: min(100%, 75rem);
  margin-top: 60px;
  padding: 30px 40px;
  border-radius: 20px;
  background: rgba(0, 0, 0, 0.3);
  -webkit-backdrop-filter: blur(10px);
  backdrop-filter: blur(10px);
  border: 1px solid rgba(255, 255, 255, 0.2);
  box-shadow: 0 8px 32px 0 rgba(0, 0, 0, 0.37);
}

.friends__title {
  font-size: 0.9rem;
  color: #ccc;
  margin-bottom: 15px;
  text-transform: uppercase;
  letter-spacing: 1px;
  text-align: center;
}

.friends__grid {
  display: grid;
  grid-template-columns: repeat(5, minmax(0, 1fr));
  gap: 10px 8px;
}

.friend-item {
  min-width: 0;
  display: inline-block;
  padding: 8px 10px;
  border-radius: 50px;
  background: rgba(0, 0, 0, 0.3);
  color: #ddd;
  text-decoration: none;
  text-align: center;
  font-size: 0.9rem;
  border: 1px solid rgba(255, 255, 255, 0.1);
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
  transition: all 0.3s ease;
}

.friend-item:hover {
  background: rgba(255, 255, 255, 0.2);
  color: #fff;
  transform: scale(1.05);
  box-shadow: 0 0 10px rgba(255, 255, 255, 0.3);
}

.friend-item--empty {
  color: #888;
  cursor: default;
}

.friend-item--empty:hover {
  background: rgba(0, 0, 0, 0.3);
  color: #aaa;
  transform: none;
  box-shadow: none;
}

[data-theme='light'] .friends {
  background: rgba(255, 255, 255, 0.45);
  border-color: rgba(255, 255, 255, 0.8);
  box-shadow: 0 8px 32px 0 rgba(90, 110, 160, 0.25);
}

[data-theme='light'] .friends__title {
  color: var(--color-muted);
}

[data-theme='light'] .friend-item {
  background: rgba(255, 255, 255, 0.65);
  border-color: rgba(255, 255, 255, 0.85);
  color: var(--color-secondary);
}

[data-theme='light'] .friend-item:hover {
  background: #fff;
  color: var(--color-foreground);
  box-shadow: 0 0 10px rgba(90, 110, 160, 0.25);
}

[data-theme='light'] .friend-item--empty {
  color: var(--color-muted);
}

[data-theme='light'] .friend-item--empty:hover {
  background: rgba(255, 255, 255, 0.65);
  color: var(--color-muted);
}

.portal__bottom {
  display: flex;
  gap: var(--space-4);
  margin-top: var(--space-8);
}

.portal__link {
  padding: 0.5rem 1.1rem;
  border-radius: 999px;
  border: 1px solid var(--glass-border);
  background: var(--glass-bg);
  color: var(--color-secondary);
  font-size: 0.85rem;
  font-weight: 500;
  transition: border-color var(--dur-fast) var(--ease-out),
    color var(--dur-fast) var(--ease-out),
    box-shadow var(--dur-fast) var(--ease-out);
}

.portal__link:hover {
  border-color: var(--color-accent);
  color: var(--color-accent);
  box-shadow: 0 0 14px rgba(56, 189, 248, 0.3);
}

@media (max-width: 480px) {
  .portal__avatar {
    width: 2.75rem;
    height: 2.75rem;
  }

  .portal__name {
    font-size: 1.55rem;
  }

  .portal__bio {
    font-size: 0.8rem;
    letter-spacing: 0.16em;
  }

  .friends {
    padding: 15px 14px;
  }

  .friend-item {
    font-size: 0.72rem;
    padding: 6px 2px;
  }
}

/* ---------- Utilities ---------- */

.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;
}

/* ---------- Responsive ---------- */

@media (max-width: 900px) {
  .bio {
    grid-template-columns: auto 1fr;
  }

  .bio__cta {
    grid-column: 1 / span 2;
    justify-self: start;
  }
}

@media (max-width: 700px) {
  .nav-toggle {
    display: inline-flex;
  }

  .nav__list {
    position: fixed;
    inset: 4.25rem 0 auto 0;
    flex-direction: column;
    align-items: stretch;
    gap: 0;
    background: rgba(10, 14, 30, 0.82);
    -webkit-backdrop-filter: blur(20px) var(--glass-saturate);
    backdrop-filter: blur(20px) var(--glass-saturate);
    border-bottom: 1px solid var(--glass-border);
    padding: var(--space-4) var(--gutter) var(--space-6);
    transform: translateY(-110%);
    transition: transform var(--dur-base) var(--ease-out);
    z-index: 40;
  }

  [data-theme='light'] .nav__list {
    background: rgba(255, 255, 255, 0.8);
  }

  .nav__list.is-open {
    transform: translateY(0);
  }

  .nav__link {
    padding-block: var(--space-4);
    font-size: 1.05rem;
    border-bottom: 1px solid var(--glass-border);
  }

  .article-nav {
    grid-template-columns: 1fr;
  }

  .article-nav__link--next {
    text-align: left;
  }

  .bio {
    grid-template-columns: 1fr;
    text-align: center;
    justify-items: center;
  }

  .bio__avatar {
    width: 6.5rem;
    height: 6.5rem;
  }

  .article-nav {
    grid-template-columns: 1fr;
  }

  .footer__grid {
    flex-direction: column;
    align-items: flex-start;
  }
}

/* ---------- Reduced motion ---------- */

@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;
  }

  .reveal {
    opacity: 1;
    transform: none;
  }
}