/* ==========================================================================
   mechanic.stream -- Manual of Precision Mechanism
   Navy-metallic palette, terminal-scholarly typography, immersive scroll
   ========================================================================== */

/* --------------------------------------------------------------------------
   1. RESET & ROOT TOKENS
   -------------------------------------------------------------------------- */

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

:root {
    /* Color palette -- Navy Metallic */
    --c-midnight-hull:    #0A0F1A;
    --c-engine-room:      #121B2E;
    --c-polished-brass:   #C9A84C;
    --c-machined-silver:  #8FA4B8;
    --c-patina-green:     #5A8F7B;
    --c-pale-steel:       #C8CDD3;
    --c-forge-ember:      #D4654A;
    --c-lamplight:        #E8D5A3;
    --c-deep-navy:        #1E3A5F;

    /* Typography */
    --f-serif:    "Source Serif 4", "IBM Plex Serif", Georgia, serif;
    --f-sans:     "Source Sans 3", "Inter", system-ui, sans-serif;
    --f-mono:     "IBM Plex Mono", "Space Mono", Menlo, monospace;
    --f-display:  "Cormorant Garamond", "Cormorant", Georgia, serif;

    /* Layout */
    --gutter-left:    8vw;   /* spine zone */
    --content-start:  12vw;
    --content-width:  52vw;
    --margin-start:   68vw;
    --margin-width:   20vw;
    --gutter-right:   12vw;

    /* Motion */
    --ease-out:    cubic-bezier(0.22, 0.61, 0.36, 1);
    --ease-in-out: cubic-bezier(0.65, 0, 0.35, 1);
}

html {
    scroll-behavior: smooth;
    background: var(--c-midnight-hull);
}

body {
    background: var(--c-midnight-hull);
    color: var(--c-pale-steel);
    font-family: var(--f-sans);
    font-size: 17px;
    line-height: 1.65;
    letter-spacing: 0.005em;
    overflow-x: hidden;
    min-height: 100vh;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
    text-rendering: optimizeLegibility;
}

/* --------------------------------------------------------------------------
   2. BACKGROUND GRID PLANE
   -------------------------------------------------------------------------- */

.bg-grid {
    position: fixed;
    inset: 0;
    pointer-events: none;
    z-index: 0;
    background-image:
        linear-gradient(to right, rgba(143, 164, 184, 0.022) 1px, transparent 1px),
        linear-gradient(to bottom, rgba(143, 164, 184, 0.022) 1px, transparent 1px);
    background-size: 64px 64px;
    background-position: 0 0;
}

.bg-grid::after {
    content: "";
    position: absolute;
    inset: 0;
    background:
        radial-gradient(ellipse 80% 60% at 80% 10%, rgba(201, 168, 76, 0.04), transparent 60%),
        radial-gradient(ellipse 60% 40% at 10% 80%, rgba(30, 58, 95, 0.25), transparent 60%);
}

/* --------------------------------------------------------------------------
   3. SPINE ARCHITECTURE
   -------------------------------------------------------------------------- */

.spine {
    position: fixed;
    top: 0;
    left: 0;
    width: var(--gutter-left);
    height: 100vh;
    z-index: 5;
    pointer-events: none;
}

.spine-line {
    position: absolute;
    top: 0;
    left: var(--gutter-left);
    width: 1px;
    height: 100%;
    background: var(--c-machined-silver);
    opacity: 0.55;
    transform: translateX(-1px);
}

.spine-line::before {
    /* faint brass highlight on top portion that follows scroll */
    content: "";
    position: absolute;
    top: 0;
    left: 0;
    width: 1px;
    height: var(--scroll-progress, 0%);
    background: linear-gradient(to bottom,
        var(--c-polished-brass) 0%,
        var(--c-polished-brass) 80%,
        rgba(201, 168, 76, 0.0) 100%);
    opacity: 0.85;
    transition: height 0.18s var(--ease-out);
}

.spine-ticks {
    position: absolute;
    top: 0;
    left: var(--gutter-left);
    width: 24px;
    height: 100%;
    transform: translateX(-12px);
}

.spine-tick {
    position: absolute;
    left: 0;
    width: 24px;
    height: 1px;
    background: var(--c-machined-silver);
    opacity: 0;
    transform: scaleX(0.3);
    transform-origin: left center;
    transition:
        opacity 0.4s var(--ease-out),
        transform 0.5s var(--ease-out),
        background-color 0.4s var(--ease-out);
}

.spine-tick::after {
    content: attr(data-tick);
    position: absolute;
    left: 30px;
    top: -7px;
    font-family: var(--f-mono);
    font-size: 10px;
    letter-spacing: 0.1em;
    color: var(--c-patina-green);
    opacity: 0;
    transition: opacity 0.5s var(--ease-out) 0.1s;
}

.spine-tick.active {
    opacity: 1;
    transform: scaleX(1);
    background: var(--c-polished-brass);
}

.spine-tick.active::after {
    opacity: 0.85;
    color: var(--c-polished-brass);
}

.spine-tick.visible {
    opacity: 0.6;
    transform: scaleX(1);
}

.spine-tick.visible::after {
    opacity: 0.5;
}

/* Tick positions: center of each section */
.spine-tick:nth-child(1) { top: 10vh; }
.spine-tick:nth-child(2) { top: calc(100vh + 10vh); }
.spine-tick:nth-child(3) { top: calc(200vh + 10vh); }
.spine-tick:nth-child(4) { top: calc(300vh + 10vh); }
.spine-tick:nth-child(5) { top: calc(400vh + 10vh); }

.spine-label {
    position: fixed;
    top: 50%;
    left: 1.6vw;
    transform: translateY(-50%) rotate(-90deg);
    transform-origin: left center;
    font-family: var(--f-mono);
    font-size: 10px;
    letter-spacing: 0.45em;
    color: var(--c-machined-silver);
    opacity: 0.45;
    white-space: nowrap;
}

/* --------------------------------------------------------------------------
   4. PAGE / SECTION FRAMEWORK
   -------------------------------------------------------------------------- */

.manual {
    position: relative;
    z-index: 1;
    width: 100%;
}

.page {
    position: relative;
    min-height: 100vh;
    width: 100%;
    padding: 8vh 0 4vh 0;
    display: block;
    overflow: hidden;
    opacity: 0;
    transform: scale(1.02);
    transition:
        opacity 0.6s var(--ease-out),
        transform 0.6s var(--ease-out);
}

.page.in-view {
    opacity: 1;
    transform: scale(1.0);
}

.page.alt-bg {
    background: linear-gradient(180deg,
        var(--c-midnight-hull) 0%,
        var(--c-engine-room) 50%,
        var(--c-midnight-hull) 100%);
}

/* --------------------------------------------------------------------------
   5. GHOST NUMERALS
   -------------------------------------------------------------------------- */

.ghost-numeral {
    position: absolute;
    top: 50%;
    left: 1vw;
    transform: translateY(-50%);
    font-family: var(--f-display);
    font-weight: 300;
    font-size: 200px;
    line-height: 1;
    color: transparent;
    -webkit-text-stroke: 1px rgba(143, 164, 184, 0.18);
    text-stroke: 1px rgba(143, 164, 184, 0.18);
    opacity: 0.85;
    pointer-events: none;
    user-select: none;
    z-index: 0;
}

.ghost-final {
    left: 50%;
    transform: translate(-50%, -50%);
    font-size: 360px;
    -webkit-text-stroke: 1px rgba(143, 164, 184, 0.12);
}

/* --------------------------------------------------------------------------
   6. CONTENT COLUMN
   -------------------------------------------------------------------------- */

.content-column {
    position: relative;
    margin-left: var(--content-start);
    width: var(--content-width);
    z-index: 2;
}

.margin-column {
    position: absolute;
    top: 14vh;
    left: var(--margin-start);
    width: var(--margin-width);
    z-index: 2;
    display: flex;
    flex-direction: column;
    gap: 28px;
}

/* --------------------------------------------------------------------------
   7. TYPOGRAPHY
   -------------------------------------------------------------------------- */

.meta-line, .chapter-label {
    font-family: var(--f-mono);
    font-size: 12px;
    font-weight: 400;
    letter-spacing: 0.32em;
    text-transform: uppercase;
    color: var(--c-patina-green);
    margin-bottom: 28px;
    opacity: 0;
    transform: translateY(20px);
    transition: opacity 0.6s var(--ease-out) 0.1s, transform 0.6s var(--ease-out) 0.1s;
}

.in-view .meta-line,
.in-view .chapter-label {
    opacity: 0.92;
    transform: translateY(0);
}

.book-title {
    font-family: var(--f-serif);
    font-weight: 700;
    font-size: clamp(56px, 9vw, 128px);
    line-height: 0.98;
    letter-spacing: -0.025em;
    color: var(--c-polished-brass);
    margin-bottom: 36px;
    opacity: 0;
    transform: translateY(24px);
    transition: opacity 0.7s var(--ease-out) 0.2s, transform 0.7s var(--ease-out) 0.2s;
}

.in-view .book-title { opacity: 1; transform: translateY(0); }

.title-line-a, .title-line-b {
    display: block;
}

.title-dot {
    display: inline-block;
    color: var(--c-forge-ember);
    transform: translateY(-0.05em);
    margin-left: -0.05em;
    margin-right: -0.04em;
    font-style: italic;
}

.title-line-a {
    text-shadow: 0 0 18px rgba(201, 168, 76, 0.18);
}

.title-line-b {
    margin-left: 0.5em;
    color: var(--c-pale-steel);
    -webkit-text-stroke: 0.5px var(--c-machined-silver);
}

.section-heading {
    font-family: var(--f-serif);
    font-weight: 700;
    font-size: clamp(36px, 4.5vw, 64px);
    line-height: 1.08;
    letter-spacing: -0.02em;
    color: var(--c-polished-brass);
    margin-bottom: 32px;
    opacity: 0;
    transform: translateY(20px);
    transition: opacity 0.7s var(--ease-out) 0.2s, transform 0.7s var(--ease-out) 0.2s;
}

.in-view .section-heading { opacity: 1; transform: translateY(0); }

.subtitle {
    font-family: var(--f-serif);
    font-weight: 400;
    font-style: italic;
    font-size: clamp(18px, 1.5vw, 22px);
    line-height: 1.5;
    color: var(--c-pale-steel);
    max-width: 44ch;
    margin-bottom: 22px;
    opacity: 0;
    transform: translateY(20px);
    transition: opacity 0.6s var(--ease-out) 0.4s, transform 0.6s var(--ease-out) 0.4s;
}

.in-view .subtitle { opacity: 0.94; transform: translateY(0); }

.byline {
    font-family: var(--f-mono);
    font-size: 12px;
    letter-spacing: 0.18em;
    text-transform: uppercase;
    color: var(--c-machined-silver);
    opacity: 0;
    transform: translateY(20px);
    transition: opacity 0.6s var(--ease-out) 0.55s, transform 0.6s var(--ease-out) 0.55s;
}

.in-view .byline { opacity: 0.7; transform: translateY(0); }

.lede {
    font-family: var(--f-serif);
    font-weight: 400;
    font-size: clamp(19px, 1.5vw, 22px);
    line-height: 1.5;
    color: var(--c-pale-steel);
    margin-bottom: 26px;
    max-width: 50ch;
    opacity: 0;
    transform: translateY(20px);
    transition: opacity 0.6s var(--ease-out) 0.35s, transform 0.6s var(--ease-out) 0.35s;
}

.in-view .lede { opacity: 1; transform: translateY(0); }

.body-text {
    font-family: var(--f-sans);
    font-weight: 400;
    font-size: 17px;
    line-height: 1.7;
    letter-spacing: 0.005em;
    color: var(--c-pale-steel);
    margin-bottom: 22px;
    max-width: 50ch;
    opacity: 0;
    transform: translateY(18px);
    transition: opacity 0.55s var(--ease-out), transform 0.55s var(--ease-out);
}

.body-text:nth-of-type(1) { transition-delay: 0.45s; }
.body-text:nth-of-type(2) { transition-delay: 0.55s; }
.body-text:nth-of-type(3) { transition-delay: 0.65s; }
.body-text:nth-of-type(4) { transition-delay: 0.75s; }

.in-view .body-text { opacity: 0.95; transform: translateY(0); }

.emphasis {
    font-weight: 600;
    color: var(--c-lamplight);
    font-style: italic;
}

.terminal-text {
    font-family: var(--f-mono);
    font-size: 0.92em;
    color: var(--c-patina-green);
    letter-spacing: 0.02em;
    padding: 0 0.25em;
    background: rgba(90, 143, 123, 0.06);
    border-radius: 2px;
}

.warning-text {
    font-family: var(--f-mono);
    font-weight: 500;
    color: var(--c-forge-ember);
    letter-spacing: 0.08em;
    text-transform: uppercase;
    font-size: 0.92em;
}

/* Inline links -- underline draw from left */
.inline-link {
    position: relative;
    color: var(--c-polished-brass);
    cursor: pointer;
    font-weight: 500;
    text-decoration: none;
    background-image: linear-gradient(to right, var(--c-polished-brass), var(--c-polished-brass));
    background-size: 0% 1px;
    background-position: 0 100%;
    background-repeat: no-repeat;
    transition: background-size 0.4s var(--ease-out), color 0.3s var(--ease-out);
    padding-bottom: 2px;
}

.inline-link:hover {
    background-size: 100% 1px;
    color: var(--c-lamplight);
}

/* --------------------------------------------------------------------------
   8. ENGRAVED RULE
   -------------------------------------------------------------------------- */

.engraved-rule {
    display: flex;
    align-items: center;
    width: 100%;
    max-width: 50ch;
    margin: 30px 0 30px 0;
    gap: 4px;
    height: 12px;
    opacity: 0;
    transform: scaleX(0.7);
    transform-origin: left center;
    transition: opacity 0.7s var(--ease-out) 0.5s, transform 0.7s var(--ease-out) 0.5s;
}

.in-view .engraved-rule { opacity: 1; transform: scaleX(1); }

.rule-hairline {
    flex: 1;
    height: 0.5px;
    background: var(--c-polished-brass);
    opacity: 0.6;
    align-self: center;
    margin-block: 4px;
}

.rule-line {
    flex: 6;
    height: 1px;
    background: var(--c-machined-silver);
    opacity: 0.7;
}

.rule-diamond {
    color: var(--c-polished-brass);
    font-size: 8px;
    line-height: 1;
    margin: 0 8px;
    opacity: 0.85;
}

/* The full composite rule (hairline + line + diamond + line + hairline) */
.engraved-rule {
    flex-direction: column;
    align-items: stretch;
    height: auto;
    position: relative;
    padding: 8px 0;
}

.engraved-rule .rule-hairline:nth-child(1),
.engraved-rule .rule-hairline:nth-child(5) {
    height: 0.5px;
    width: 100%;
    flex: none;
}

.engraved-rule .rule-line:nth-child(2),
.engraved-rule .rule-line:nth-child(4) {
    display: none;
}

.engraved-rule {
    /* re-layout: top hairline + center row (line + diamond + line) + bottom hairline */
    display: grid;
    grid-template-rows: auto 1fr auto;
    gap: 4px;
}

.engraved-rule .rule-line {
    display: none;
}

.engraved-rule::before,
.engraved-rule::after {
    /* not used; using direct elements */
    content: none;
}

/* Simpler: rebuild engraved-rule with flex row containing all 5 children */
.engraved-rule {
    display: flex;
    flex-direction: row;
    align-items: center;
    gap: 0;
    height: auto;
    padding: 0;
    margin: 30px 0;
    position: relative;
}

.engraved-rule .rule-hairline {
    flex: 0 0 auto;
    width: 36px;
    height: 0.5px;
    background: var(--c-polished-brass);
    opacity: 0.7;
    align-self: center;
}

.engraved-rule .rule-line {
    display: block;
    flex: 1 1 auto;
    height: 1px;
    background: var(--c-machined-silver);
    opacity: 0.7;
    align-self: center;
}

.engraved-rule .rule-diamond {
    flex: 0 0 auto;
    margin: 0 14px;
    color: var(--c-polished-brass);
    font-size: 9px;
    line-height: 1;
    opacity: 0.95;
    transform: translateY(-1px);
}

/* --------------------------------------------------------------------------
   9. MARGIN BLOCKS, ANNOTATIONS, DIAGRAMS
   -------------------------------------------------------------------------- */

.margin-block {
    position: relative;
    padding: 14px 16px;
    border: 1px solid rgba(143, 164, 184, 0.22);
    background: rgba(18, 27, 46, 0.35);
    backdrop-filter: blur(2px);
    transition:
        transform 0.35s var(--ease-in-out),
        box-shadow 0.35s var(--ease-in-out),
        border-color 0.35s var(--ease-in-out);
    transform-origin: top left;
    opacity: 0;
}

.margin-block[data-rotate="-2"] { transform: rotate(-2deg); }
.margin-block[data-rotate="-3"] { transform: rotate(-3deg); }
.margin-block[data-rotate="2"]  { transform: rotate(2deg); }
.margin-block[data-rotate="3"]  { transform: rotate(3deg); }

.in-view .margin-block {
    opacity: 1;
    transition:
        opacity 0.5s var(--ease-out),
        transform 0.5s var(--ease-in-out),
        box-shadow 0.35s var(--ease-in-out),
        border-color 0.35s var(--ease-in-out);
}

.in-view .margin-block:nth-child(1) { transition-delay: 0.7s; }
.in-view .margin-block:nth-child(2) { transition-delay: 0.85s; }
.in-view .margin-block:nth-child(3) { transition-delay: 1.0s; }
.in-view .margin-block:nth-child(4) { transition-delay: 1.15s; }

.mono-label {
    font-family: var(--f-mono);
    font-size: 10px;
    font-weight: 500;
    letter-spacing: 0.18em;
    color: var(--c-polished-brass);
    text-transform: uppercase;
    margin-bottom: 8px;
    opacity: 0.85;
}

.mono-note {
    font-family: var(--f-mono);
    font-size: 11px;
    line-height: 1.55;
    color: var(--c-patina-green);
    letter-spacing: 0.04em;
    opacity: 0.85;
}

.terminal-block {
    background: rgba(10, 15, 26, 0.65);
    border-color: rgba(90, 143, 123, 0.28);
    box-shadow: inset 0 0 30px rgba(90, 143, 123, 0.06);
}

.terminal-block .mono-label {
    color: var(--c-patina-green);
}

.terminal-block .mono-note {
    color: var(--c-pale-steel);
    opacity: 0.78;
}

/* HOVER-LIFT pattern */
.hover-lift {
    cursor: default;
}

.hover-lift:hover {
    transform: translateY(-4px) rotate(0deg);
    box-shadow: 0 8px 24px rgba(201, 168, 76, 0.12);
    border-color: rgba(201, 168, 76, 0.8) !important;
    transition:
        transform 0.25s var(--ease-out),
        box-shadow 0.25s var(--ease-out),
        border-color 0.25s var(--ease-out);
}

/* --------------------------------------------------------------------------
   10. SVG DIAGRAMS
   -------------------------------------------------------------------------- */

.diagram-container {
    padding: 18px 16px 12px 16px;
    border: 1px solid rgba(143, 164, 184, 0.22);
    background: rgba(18, 27, 46, 0.4);
    text-align: center;
    transform-origin: center;
}

.diagram {
    display: block;
    width: 100%;
    height: auto;
    max-width: 100%;
    margin: 0 auto;
}

.diagram .draw {
    /* path-drawing animation */
}

.diagram .draw line,
.diagram .draw circle,
.diagram .draw path,
.diagram .draw rect {
    stroke-dasharray: 1200;
    stroke-dashoffset: 1200;
    transition: stroke-dashoffset 1.5s var(--ease-in-out);
}

.in-view .diagram .draw line,
.in-view .diagram .draw circle,
.in-view .diagram .draw path,
.in-view .diagram .draw rect {
    stroke-dashoffset: 0;
}

.diagram-caption {
    font-family: var(--f-mono);
    font-size: 10px;
    letter-spacing: 0.12em;
    color: var(--c-machined-silver);
    margin-top: 10px;
    opacity: 0.7;
    text-transform: uppercase;
}

/* --------------------------------------------------------------------------
   11. LENS-FLARE EFFECTS
   -------------------------------------------------------------------------- */

.brass-flare {
    position: absolute;
    width: 64px;
    height: 64px;
    border-radius: 50%;
    background: radial-gradient(circle at 50% 50%,
        var(--c-lamplight) 0%,
        var(--c-polished-brass) 30%,
        rgba(201, 168, 76, 0.4) 55%,
        rgba(201, 168, 76, 0) 75%);
    box-shadow:
        0 0 80px 40px rgba(232, 213, 163, 0.18),
        0 0 160px 80px rgba(201, 168, 76, 0.12);
    pointer-events: none;
    z-index: 3;
    opacity: 0.85;
    animation: flare-pulse 3s var(--ease-in-out) infinite;
    will-change: transform, opacity;
}

.flare-tr { top: 12vh; right: 14vw; }
.flare-tl { top: 12vh; left: 16vw; }
.flare-center {
    top: 50%; left: 50%;
    width: 110px; height: 110px;
    transform: translate(-50%, -50%);
    box-shadow:
        0 0 140px 70px rgba(232, 213, 163, 0.22),
        0 0 280px 140px rgba(201, 168, 76, 0.14);
}

@keyframes flare-pulse {
    0%, 100% { transform: scale(1.0); opacity: 0.85; }
    50%      { transform: scale(1.05); opacity: 1.0; }
}

.flare-center {
    animation-name: flare-pulse-center;
}

@keyframes flare-pulse-center {
    0%, 100% { transform: translate(-50%, -50%) scale(1.0); opacity: 0.85; }
    50%      { transform: translate(-50%, -50%) scale(1.05); opacity: 1.0; }
}

/* Silver streaks */
.silver-streak {
    position: absolute;
    left: 0;
    width: 100%;
    height: 1px;
    pointer-events: none;
    z-index: 3;
    background: linear-gradient(90deg,
        transparent 0%,
        rgba(143, 164, 184, 0.0) 8%,
        rgba(143, 164, 184, 0.18) 50%,
        rgba(143, 164, 184, 0.0) 92%,
        transparent 100%);
    box-shadow: 0 0 8px rgba(143, 164, 184, 0.08);
}

.streak-top    { top: 6vh; }
.streak-bottom { bottom: 8vh; }
.streak-mid    { top: 50%; }

/* Green phosphor glow behind terminal blocks */
.terminal-block::before {
    content: "";
    position: absolute;
    inset: -10px;
    background: radial-gradient(ellipse at center, rgba(90, 143, 123, 0.08), transparent 70%);
    z-index: -1;
    pointer-events: none;
}

/* --------------------------------------------------------------------------
   12. FOLIO MARKS
   -------------------------------------------------------------------------- */

.folio {
    position: absolute;
    bottom: 3vh;
    right: var(--gutter-right);
    font-family: var(--f-mono);
    font-size: 10px;
    letter-spacing: 0.22em;
    color: var(--c-machined-silver);
    opacity: 0.6;
    text-transform: uppercase;
}

.folio:hover {
    color: var(--c-polished-brass);
    opacity: 1;
    transform: translateY(-4px);
    transition: transform 0.25s var(--ease-out), color 0.25s var(--ease-out), opacity 0.25s var(--ease-out);
}

/* --------------------------------------------------------------------------
   13. SECTION I (TITLE PAGE) SPECIAL
   -------------------------------------------------------------------------- */

.page-title {
    display: flex;
    align-items: center;
    min-height: 100vh;
    padding-top: 0;
    padding-bottom: 0;
}

.page-title .content-column {
    margin-top: 6vh;
}

.page-title .margin-column {
    top: auto;
    transform: translateY(-50%);
    top: 50%;
}

.scroll-cue {
    position: absolute;
    left: 50%;
    bottom: 5vh;
    transform: translateX(-50%);
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 8px;
    font-family: var(--f-mono);
    font-size: 10px;
    letter-spacing: 0.4em;
    color: var(--c-patina-green);
    opacity: 0.7;
    animation: cue-bob 2.6s var(--ease-in-out) infinite;
}

.cue-arrow {
    font-size: 14px;
    color: var(--c-polished-brass);
}

@keyframes cue-bob {
    0%, 100% { transform: translateX(-50%) translateY(0); opacity: 0.6; }
    50%      { transform: translateX(-50%) translateY(6px); opacity: 1.0; }
}

/* --------------------------------------------------------------------------
   14. CLOSING SECTION
   -------------------------------------------------------------------------- */

.page-closing {
    display: flex;
    align-items: center;
    justify-content: center;
    min-height: 100vh;
    padding: 0;
}

.closing-frame {
    position: relative;
    z-index: 2;
    text-align: center;
    max-width: 78vw;
    padding: 0 6vw;
    margin-left: var(--gutter-left);
}

.closing-attrib {
    font-family: var(--f-mono);
    font-size: 11px;
    letter-spacing: 0.32em;
    text-transform: uppercase;
    color: var(--c-machined-silver);
    opacity: 0.7;
    margin-bottom: 36px;
}

.closing-attrib.top {
    margin-bottom: 56px;
    color: var(--c-polished-brass);
    opacity: 0.85;
}

.pull-quote {
    font-family: var(--f-display);
    font-weight: 300;
    font-size: clamp(36px, 4.4vw, 64px);
    line-height: 1.25;
    letter-spacing: -0.01em;
    color: var(--c-pale-steel);
    max-width: 22ch;
    margin: 0 auto 36px;
    position: relative;
    opacity: 0;
    transform: translateY(20px);
    transition: opacity 1s var(--ease-out) 0.3s, transform 1s var(--ease-out) 0.3s;
}

.in-view .pull-quote { opacity: 1; transform: translateY(0); }

.quote-mark {
    font-family: var(--f-display);
    color: var(--c-polished-brass);
    font-size: 1.8em;
    line-height: 0;
    opacity: 0.7;
    vertical-align: -0.18em;
    margin: 0 0.05em;
}

.quote-emphasis {
    color: var(--c-polished-brass);
    font-style: italic;
}

.closing-rule {
    max-width: 280px;
    margin-left: auto;
    margin-right: auto;
    margin-top: 28px;
    margin-bottom: 28px;
}

.closing-domain {
    margin-top: 36px;
    font-family: var(--f-serif);
    font-weight: 700;
    font-size: clamp(18px, 1.4vw, 22px);
    letter-spacing: 0.08em;
    color: var(--c-polished-brass);
    text-shadow: 0 0 18px rgba(201, 168, 76, 0.22);
}

/* --------------------------------------------------------------------------
   15. SCROLL PROGRESS BRASS DOT
   -------------------------------------------------------------------------- */

.scroll-progress {
    position: fixed;
    top: var(--scroll-y, 0);
    left: var(--gutter-left);
    width: 8px;
    height: 8px;
    margin-left: -4px;
    margin-top: -4px;
    border-radius: 50%;
    background: var(--c-polished-brass);
    box-shadow: 0 0 12px rgba(201, 168, 76, 0.6);
    z-index: 6;
    pointer-events: none;
    opacity: 0.9;
    transition: top 0.18s var(--ease-out);
}

/* --------------------------------------------------------------------------
   16. RESPONSIVE -- collapse the three-column grid on narrow viewports
   -------------------------------------------------------------------------- */

@media (max-width: 1100px) {
    :root {
        --content-start: 14vw;
        --content-width: 76vw;
        --margin-start: 14vw;
        --margin-width: 76vw;
    }

    .margin-column {
        position: relative;
        top: auto;
        left: auto;
        margin: 40px 0 0 var(--content-start);
        width: var(--margin-width);
    }

    .ghost-numeral {
        font-size: 140px;
        opacity: 0.5;
    }

    .ghost-final { font-size: 240px; }

    .flare-tr { right: 10vw; }
    .flare-tl { left: 10vw; }
}

@media (max-width: 700px) {
    :root {
        --gutter-left: 12vw;
        --content-start: 16vw;
        --content-width: 76vw;
        --margin-start: 16vw;
        --margin-width: 76vw;
        --gutter-right: 8vw;
    }

    body { font-size: 16px; }

    .book-title { font-size: 64px; }
    .section-heading { font-size: 36px; }

    .ghost-numeral { font-size: 100px; opacity: 0.35; }

    .spine-label { display: none; }
}