:root {
   /* authoritative palette ladder (OKLCH computed) */
   --ground: #e4eae3;
   --surface: #d5dcd4;
   --surface-2: #c2cac1;
   --line: #a0a79f;
   --ink-soft: #4a4f49;
   --ink: #272a27;
   --accent: #a86515;
   --accent-ink: #fff;

   /* state tokens */
   --accent-hover: #8f540f;
   --accent-active: #78450a;
   --focus-ring: #272a27;
   --error-ink: #8b2519;
   --error-bg: #eed7d4;
   --error-line: #cc7b70;

   /* typography stacks */
   --zehe-808: "Cormorant Garamond", "Cormorant Garamond Fallback", Georgia, "Times New Roman", serif;
   --zehe-90a: "Source Sans 3", "Source Sans 3 Fallback", -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
   --zehe-6a0: "JetBrains Mono", "JetBrains Mono Fallback", ui-monospace, SFMono-Regular, Menlo, monospace;

   /* modular type scale via clamp() */
   --text-xs: clamp(0.75rem, 0.72rem + 0.15vw, 0.8125rem);
   --text-sm: clamp(0.8438rem, 0.81rem + 0.18vw, 0.9375rem);
   --text-base: clamp(1rem, 0.96rem + 0.2vw, 1.0625rem);
   --text-lg: clamp(1.125rem, 1.05rem + 0.38vw, 1.25rem);
   --text-xl: clamp(1.3125rem, 1.2rem + 0.56vw, 1.5rem);
   --text-2xl: clamp(1.625rem, 1.45rem + 0.88vw, 1.875rem);
   --text-3xl: clamp(2rem, 1.7rem + 1.5vw, 2.5rem);
   --text-4xl: clamp(2.375rem, 1.95rem + 2.1vw, 3.25rem);
   --text-hero: clamp(2.625rem, 2.15rem + 2.4vw, 3.875rem);

   /* leading */
   --leading-tight: 1.15;
   --leading-snug: 1.25;
   --leading-normal: 1.55;
   --leading-relaxed: 1.68;

   /* geometry and layout */
   --site-max: 1280px;
   --reading-max: 65ch;
   --frame-pad: clamp(1rem, 0.8rem + 1vw, 2rem);
   --section-pad: clamp(3rem, 2.2rem + 4vw, 5.5rem);
   --gutter: clamp(1.25rem, 1rem + 1.2vw, 2.5rem);
   --radius-xs: 2px;
   --radius-sm: 3px;
   --radius-md: 4px;

   /* dock dimensions */
   --dock-height: 68px;

   --shadow-hairline: 0 0 0 1px var(--line);
   --shadow-subtle: 0 4px 16px -2px rgba(39, 42, 39, 0.07);
   --shadow-card: 0 8px 24px -4px rgba(39, 42, 39, 0.09);
   --shadow-elevated: 0 16px 36px -6px rgba(39, 42, 39, 0.12);

   --ease-out: cubic-bezier(0.16, 1, 0.3, 1);
   --ease-in-out: cubic-bezier(0.65, 0, 0.35, 1);
   --dur-fast: 160ms;
   --dur-med: 280ms;
   --dur-slow: 480ms;
}

/* box sizing & baseline reset */
*,
*::before,
*::after { box-sizing: border-box; }

* {
   margin: 0;
   padding: 0;
}

html {
   font-size: 100%;
   -webkit-text-size-adjust: 100%;
   text-size-adjust: 100%;
   background-color: var(--ground);
   color: var(--ink);
   scroll-behavior: smooth;
   scroll-padding-top: 1.5rem;
}

body {
   min-height: 100vh;
   font-family: var(--zehe-90a);
   font-size: var(--text-base);
   line-height: var(--leading-normal);
   color: var(--ink);
   background-color: var(--ground);
   -webkit-font-smoothing: antialiased;
   -moz-osx-font-smoothing: grayscale;
   text-rendering: optimizeLegibility;
   padding-bottom: calc(var(--dock-height) + env(safe-area-inset-bottom, 0px));
}

@media (min-width: 1080px) {
   body { padding-bottom: 0; }
}

img,
picture,
svg,
video,
canvas {
   display: block;

   max-width: 100%;
   height: auto;
}

/* headings hierarchy */
h1, h2, h3, h4, h5, h6 {
   font-family: var(--zehe-808);
   font-weight: 600;
   line-height: var(--leading-tight);
   color: var(--ink);
   letter-spacing: -0.015em;
   text-wrap: balance;
}

h1 {
   font-size: var(--text-4xl);
   font-weight: 600;
   letter-spacing: -0.02em;
}

h2 {
   font-size: var(--text-3xl);
   font-weight: 600;
}

h3 {
   font-size: var(--text-2xl);
   font-weight: 500;
}

h4 {
   font-size: var(--text-xl);
   font-weight: 500;
}

h5 {
   font-size: var(--text-lg);
   font-weight: 600;
}

h6 {
   font-size: var(--text-base);
   font-weight: 600;
   letter-spacing: 0.04em;
}

/* running copy */
p,
li,
dd {
   max-width: var(--reading-max);
   color: var(--ink-soft);
   font-size: var(--text-base);
   line-height: var(--leading-relaxed);
}

p + p { margin-top: 1rem; }

strong, b {
   font-weight: 600;
   color: var(--ink);
}

small {
   font-size: var(--text-sm);
   color: var(--ink-soft);
}

/* tabular numbers and metrics */
.num,
.tabular,
time,
data,
.spec-value,
.price-tag {
   font-family: var(--zehe-6a0);
   font-variant-numeric: tabular-nums lining-nums;
   letter-spacing: -0.02em;
}

a {
   color: var(--ink);
   text-decoration: underline;
   text-decoration-thickness: 1px;
   text-underline-offset: 3px;
   text-decoration-color: var(--line);
   transition: color var(--dur-fast) var(--ease-out),
                     text-decoration-color var(--dur-fast) var(--ease-out);
}

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

a:focus-visible {
   outline: 2px solid var(--focus-ring);
   outline-offset: 2px;
   text-decoration-color: transparent;
}

/* icon primitive */
.icon {
   width: 1.25rem;
   height: 1.25rem;
   fill: currentColor;
   flex-shrink: 0;
   pointer-events: none;
}

/* lists reset */
ul, ol { list-style: none; }

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

button { cursor: pointer; }

.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;

}

.skip-link {
   position: absolute;
   top: 0.5rem;
   left: 0.5rem;
   z-index: 1000;
   padding: 0.75rem 1.25rem;
   background-color: var(--ink);
   color: #fff;
   text-decoration: none;
   font-weight: 500;
   border-radius: var(--radius-xs);
   transform: translateY(-150%);
   transition: transform var(--dur-fast) var(--ease-out);
}

.skip-link:focus-visible {
   transform: translateY(0);
   outline: 2px solid var(--accent);
   outline-offset: 2px;
}

/* structural boxed frame (Site Blueprint: Boxed frame with tabbed sections) */
.page-frame {
   width: 100%;
   max-width: var(--site-max);
   margin-left: auto;
   margin-right: auto;
   border-left: 1px solid var(--line);
   border-right: 1px solid var(--line);
   background-color: var(--ground);
   position: relative;
   min-height: 100vh;
   min-height: 100dvh;
   display: flex;
   flex-direction: column;
}

@media (max-width: 1280px) {

   .page-frame {
      border-left: 0;
      border-right: 0;
   }
}

.frame-strip {
   border-bottom: 1px solid var(--line);
   background-color: var(--surface);
   color: var(--ink-soft);
   font-size: var(--text-xs);
   font-family: var(--zehe-6a0);
   padding: 0.4rem var(--frame-pad);
   display: flex;
   align-items: center;
   justify-content: space-between;
   gap: 1rem;
}

.frame-strip span {
   display: inline-flex;
   align-items: center;
   gap: 0.35rem;
}

@media (max-width: 640px) {
   .frame-strip .strip-optional { display: none; }
}

/* layout grid container */
.container {
   width: 100%;
   padding-left: var(--frame-pad);
   padding-right: var(--frame-pad);
   margin-left: auto;
   margin-right: auto;
}

.margin-layout {
   display: grid;
   grid-template-columns: 1fr;
   gap: 1.75rem;
}

@media (min-width: 900px) {
   .margin-layout {
      grid-template-columns: 1fr 280px;
      gap: 3.5rem;
      align-items: start;
   }
}

.reading-col { min-width: 0; }

.margin-col {
   min-width: 0;
   font-size: var(--text-sm);
   color: var(--ink-soft);
   border-left: 1px solid var(--line);
   padding-left: 1.25rem;
   display: flex;
   flex-direction: column;
   gap: 1.75rem;
}

@media (max-width: 899px) {
   .margin-col {
      border-left: 2px solid var(--line);
      padding-left: 1rem;
      margin-top: 0.5rem;
   }
}

.margin-note {
   display: flex;
   flex-direction: column;
   gap: 0.35rem;
   font-size: var(--text-sm);
   line-height: var(--leading-snug);
   position: relative;
   z-index: 1;
   clear: both;
}

.margin-note .note-label {
   font-family: var(--zehe-6a0);
   font-size: var(--text-xs);
   color: var(--ink);
   text-transform: uppercase;
   letter-spacing: 0.05em;
   font-weight: 500;
}

.margin-note .note-value {
   font-family: var(--zehe-6a0);
   color: var(--accent) !important;
   font-weight: 600;
}

.section {
   padding-top: var(--section-pad);
   padding-bottom: var(--section-pad);
   border-bottom: 1px solid var(--line);
}

.section-tight {
   padding-top: calc(var(--section-pad) * 0.65);
   padding-bottom: calc(var(--section-pad) * 0.65);
}

/* surface utilities */
.surface-panel {
   background-color: var(--surface);
   border: 1px solid var(--line);
   border-radius: var(--radius-xs);
}

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

@media (pointer: coarse), (max-width: 768px) {
   .margin-note a,
   .margin-col a {
      display: inline-flex;
      align-items: center;
      min-height: 44px;
      padding: 6px 2px;
   }
}

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

   *,
   *::before,
   *::after {
      animation-duration: 0.001ms !important;
      animation-iteration-count: 1 !important;
      transition-duration: 0.001ms !important;
   }
}