:root{
  /* Refined color system with warmer undertones */
  --clr-bg: #0a0b0f;
  --clr-bg-elev: #111218;
  --clr-surface: #0e0f14;
  --clr-text: #f0f2f7;
  --clr-text-muted: #a8b0c0;
  --clr-line: #1a1c24;
  --clr-accent: #6ba3f5;
  --clr-accent-ink: #0d1b2e;

  /* Sophisticated typography */
  --ff-sans: -apple-system, BlinkMacSystemFont, "Segoe UI", system-ui, sans-serif;
  --ff-serif: "STIX Two Text", "Times New Roman", serif;
  --ff-mono: "SF Mono", Menlo, Monaco, Consolas, monospace;

  /* Refined type scale */
  --fs-0: clamp(11px, 0.7rem + 0.1vw, 12px);
  --fs-1: clamp(14px, 0.85rem + 0.2vw, 16px);
  --fs-2: clamp(16px, 0.95rem + 0.3vw, 18px);
  --fs-3: clamp(20px, 1.15rem + 0.5vw, 24px);
  --fs-4: clamp(28px, 1.5rem + 0.8vw, 36px);
  --fs-5: clamp(36px, 1.9rem + 1vw, 46px);
  --fs-6: clamp(48px, 2.4rem + 1.4vw, 64px);

  /* Generous spacing system */
  --radius-1: 8px; --radius-2: 12px; --radius-pill: 100px;
  --gap-1: 4px; --gap-2: 8px; --gap-3: 16px; --gap-4: 24px; --gap-5: 40px; --gap-6: 64px; --gap-7: 96px; --gap-8: 128px;
  --container: 1200px; --grid-gap: 32px;

  /* Sophisticated effects */
  --shdw-1: 0 1px 0 rgba(255,255,255,0.03), 0 8px 32px rgba(0,0,0,0.4);
  --shdw-2: 0 2px 0 rgba(255,255,255,0.04), 0 16px 48px rgba(0,0,0,0.5);
  --shdw-focus: 0 0 0 3px rgba(107, 163, 245, 0.3);
  --t-fast: 150ms cubic-bezier(0.2, 0.6, 0.2, 1); --t-med: 250ms cubic-bezier(0.2, 0.6, 0.2, 1);
  --measure: 65ch;
}

/* Light mode styles - applies for both system preference and manual override */
@media (prefers-color-scheme: light){
  :root{
    --clr-bg: #fbfbfd;
    --clr-bg-elev: #ffffff;
    --clr-surface: #ffffff;
    --clr-text: #0c0d10;
    --clr-text-muted: #5c6574;
    --clr-line: #e8eaf0;
    --clr-accent: #1b66d2;
    --clr-accent-ink: #e8f1ff;
    --shdw-1: 0 1px 0 rgba(0,0,0,0.04), 0 6px 24px rgba(0,0,0,0.08);
    --shdw-2: 0 2px 0 rgba(0,0,0,0.06), 0 12px 40px rgba(0,0,0,0.12);
  }
}

/* Manual theme overrides via data-theme attribute */
[data-theme="light"]{
  --clr-bg: #fbfbfd;
  --clr-bg-elev: #ffffff;
  --clr-surface: #ffffff;
  --clr-text: #0c0d10;
  --clr-text-muted: #5c6574;
  --clr-line: #e8eaf0;
  --clr-accent: #1b66d2;
  --clr-accent-ink: #e8f1ff;
  --shdw-1: 0 1px 0 rgba(0,0,0,0.04), 0 6px 24px rgba(0,0,0,0.08);
  --shdw-2: 0 2px 0 rgba(0,0,0,0.06), 0 12px 40px rgba(0,0,0,0.12);
}

[data-theme="dark"]{
  --clr-bg: #0a0b0f;
  --clr-bg-elev: #111218;
  --clr-surface: #0e0f14;
  --clr-text: #f0f2f7;
  --clr-text-muted: #a8b0c0;
  --clr-line: #1a1c24;
  --clr-accent: #6ba3f5;
  --clr-accent-ink: #0d1b2e;
  --shdw-1: 0 1px 0 rgba(255,255,255,0.03), 0 8px 32px rgba(0,0,0,0.4);
  --shdw-2: 0 2px 0 rgba(255,255,255,0.04), 0 16px 48px rgba(0,0,0,0.5);
}

*{box-sizing:border-box}
html,body{height:100%}
body{background:var(--clr-bg);color:var(--clr-text);font-family:var(--ff-sans);font-size:var(--fs-1);line-height:1.6;letter-spacing:-0.01em;-webkit-font-smoothing:antialiased;text-rendering:optimizeLegibility;margin:0}
.container{max-width:var(--container);margin-inline:auto;padding-inline:clamp(20px,5vw,48px)}
.stack>*+*{margin-top:var(--gap-4)}
.cluster{display:flex;flex-wrap:wrap;gap:var(--gap-3);align-items:center}
.grid{display:grid;gap:var(--grid-gap);grid-template-columns:repeat(12,minmax(0,1fr))}
.span-12{grid-column:span 12}.span-7{grid-column:span 7}.span-6{grid-column:span 6}.span-5{grid-column:span 5}
@media (max-width:900px){.grid{grid-template-columns:1fr}.span-12,.span-7,.span-6,.span-5{grid-column:auto}}

/* Typography with more sophistication */
h1,h2,h3{font-family:var(--ff-serif);font-weight:600;letter-spacing:-0.02em;margin:0 0 var(--gap-3);line-height:1.1}
h1{font-size:var(--fs-6)}
h2{font-size:var(--fs-4)}
h3{font-size:var(--fs-3)}
p{max-width:var(--measure);margin:0 0 var(--gap-3)}
.lead{font-size:var(--fs-2);color:var(--clr-text-muted);line-height:1.5;letter-spacing:-0.005em}
.small{font-size:var(--fs-0);color:var(--clr-text-muted)}
.kicker{font-size:var(--fs-0);text-transform:uppercase;letter-spacing:0.12em;color:var(--clr-text-muted);font-weight:500;margin-bottom:var(--gap-3)}
hr{border:0;height:1px;background:var(--clr-line);margin:var(--gap-6) 0}
code,kbd,pre{font-family:var(--ff-mono)}

a{color:var(--clr-accent);text-decoration:none;transition:color var(--t-fast)}
a:hover{text-decoration:underline}

/* Premium button styling */
.btn{display:inline-flex;align-items:center;justify-content:center;gap:0.5em;padding:0.9em 1.8em;border-radius:var(--radius-pill);border:1px solid transparent;text-decoration:none;font-weight:500;font-size:var(--fs-1);letter-spacing:-0.005em;transition:all var(--t-fast);cursor:pointer;position:relative;overflow:hidden}
.btn--primary{background:linear-gradient(135deg,var(--clr-accent),color-mix(in srgb,var(--clr-accent) 85%,#000));color:var(--clr-bg);box-shadow:0 2px 8px rgba(107,163,245,0.25)}
.btn--primary:hover{transform:translateY(-1px);box-shadow:0 4px 16px rgba(107,163,245,0.35)}
.btn--ghost{background:transparent;border:1px solid color-mix(in srgb,var(--clr-line) 150%,transparent);color:var(--clr-text)}
.btn--ghost:hover{border-color:var(--clr-accent);background:color-mix(in srgb,var(--clr-accent) 8%,transparent);transform:translateY(-1px)}
.btn:focus-visible{outline:none;box-shadow:var(--shdw-focus)}

input,textarea{width:100%;background:var(--clr-bg-elev);color:var(--clr-text);border:1px solid var(--clr-line);border-radius:var(--radius-1);padding:0.9em 1.1em;font-family:inherit;transition:all var(--t-fast)}
input::placeholder,textarea::placeholder{color:var(--clr-text-muted)}
input:focus,textarea:focus{outline:none;border-color:var(--clr-accent);box-shadow:var(--shdw-focus)}
label{display:block;margin-bottom:var(--gap-2);font-weight:500}

/* Premium card styling */
.card{background:linear-gradient(135deg,var(--clr-surface),color-mix(in srgb,var(--clr-surface) 95%,var(--clr-accent)));border:1px solid var(--clr-line);border-radius:var(--radius-2);padding:clamp(20px,3vw,32px);box-shadow:var(--shdw-1);transition:all var(--t-med);position:relative}
.card:hover{transform:translateY(-2px);box-shadow:var(--shdw-2);border-color:color-mix(in srgb,var(--clr-line) 150%,var(--clr-accent))}
.card--inline>*+*{margin-top:var(--gap-3)}

/* Refined navigation */
.header{position:sticky;top:0;z-index:10;backdrop-filter:saturate(140%) blur(20px);background:color-mix(in srgb,var(--clr-bg) 80%,transparent);border-bottom:1px solid var(--clr-line)}
.nav{display:flex;justify-content:space-between;align-items:center;height:72px}
.brand{font-family:var(--ff-serif);font-weight:600;font-size:var(--fs-2);letter-spacing:-0.01em}
.nav a{color:var(--clr-text);text-decoration:none;opacity:0.8;transition:opacity var(--t-fast);font-size:var(--fs-1)}
.nav a:hover{opacity:1}

.footer{border-top:1px solid var(--clr-line);color:var(--clr-text-muted);padding:var(--gap-6) 0;margin-top:var(--gap-8)}

/* Blockquote styling */
blockquote{margin:0;position:relative}
blockquote::before{content:'';position:absolute;left:-4px;top:0;bottom:0;width:3px;background:var(--clr-accent);border-radius:2px}

/* Motion (optional; safe defaults) */
.reveal{opacity:0;transform:translateY(6px);transition:opacity var(--t-med),transform var(--t-med)}
.reveal.is-in{opacity:1;transform:none}

/* Responsive adjustments */
@media (max-width:768px){
  .nav{height:64px}
  .cluster{gap:var(--gap-2)}
  .btn{padding:0.8em 1.5em}
}

@media (prefers-reduced-motion: reduce){*{animation:none !important;transition:none !important;scroll-behavior:auto !important}}

/* Theme transitions */
* {
  transition: background-color var(--t-med), border-color var(--t-med),
              color var(--t-med), box-shadow var(--t-med);
}

.theme-toggle, .theme-toggle * {
  transition: transform var(--t-fast), opacity var(--t-fast) !important;
}

/* Theme toggle styling */
.theme-toggle {
  position: relative;
  width: 44px;
  height: 44px;
  border: 1px solid var(--clr-line);
  border-radius: 50%;
  background: var(--clr-surface);
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: center;
  transition: all var(--t-fast);
  margin-left: var(--gap-3);
}

.theme-toggle:hover {
  border-color: var(--clr-accent);
  transform: translateY(-1px);
  box-shadow: var(--shdw-1);
}

.theme-toggle:focus-visible {
  outline: none;
  box-shadow: var(--shdw-focus);
}

.theme-icon {
  width: 18px;
  height: 18px;
  color: var(--clr-text);
  transition: transform var(--t-fast), opacity var(--t-fast);
}

.theme-toggle[aria-pressed="false"] .theme-icon--light {
  transform: rotate(-90deg);
  opacity: 0;
}

.theme-toggle[aria-pressed="true"] .theme-icon--dark {
  transform: rotate(90deg);
  opacity: 0;
}

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

/* Email obfuscation styles */
.email-text {
  unicode-bidi: bidi-override;
  direction: ltr;
  user-select: all;
  -webkit-user-select: all;
}

.email-link {
  position: relative;
  cursor: pointer;
}

@media (max-width: 768px) {
  .theme-toggle {
    width: 40px;
    height: 40px;
  }

  .theme-icon {
    width: 16px;
    height: 16px;
  }
}