/* ============================================================
   Q Continuum — A Philosophy of Existence and Consciousness
   Palette drawn from the book cover: deep navy, off-white,
   light blue accent.
   ============================================================ */

:root {
    /* Core palette */
    --navy-900: #0b1526;
    --navy-800: #10203a;
    --navy-700: #1a2d4d;
    --navy-600: #24406b;

    --blue-400: #5a9fd4;
    --blue-300: #7fb8e3;
    --blue-200: #a8d0ee;

    --paper:    #f7f8fa;
    --paper-2:  #eef1f6;
    --white:    #ffffff;

    --ink:        #1c2635;
    --ink-muted:  #55637a;
    --ink-faint:  #8593a8;

    --on-dark:        #eaf0f8;
    --on-dark-muted:  rgba(234, 240, 248, 0.72);
    --on-dark-faint:  rgba(234, 240, 248, 0.48);

    /* Typography */
    --font-serif: 'Cormorant Garamond', Georgia, 'Times New Roman', serif;
    --font-sans:  'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;

    /* Rhythm */
    --space-section: clamp(4.5rem, 10vw, 8rem);
    --radius:    4px;
    --radius-lg: 8px;
    --measure:   68ch;

    --shadow-cover: 0 30px 60px -18px rgba(0, 0, 0, 0.55);
    --shadow-card:  0 1px 2px rgba(16, 32, 58, 0.05),
                    0 8px 24px -12px rgba(16, 32, 58, 0.18);

    --ease: cubic-bezier(0.4, 0, 0.2, 1);
}

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

html {
    scroll-behavior: smooth;
    /* offset for the sticky navbar when jumping to anchors */
    scroll-padding-top: 5.5rem;
    -webkit-text-size-adjust: 100%;
}

body {
    margin: 0;
    font-family: var(--font-sans);
    font-size: clamp(1rem, 0.96rem + 0.2vw, 1.0625rem);
    font-weight: 400;
    line-height: 1.7;
    color: var(--ink);
    background-color: var(--paper);
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
}

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

h1, h2, h3 {
    font-family: var(--font-serif);
    font-weight: 500;
    line-height: 1.15;
    letter-spacing: -0.01em;
    margin: 0;
}

p { margin: 0 0 1.15em; }
p:last-child { margin-bottom: 0; }

a { color: inherit; }

::selection {
    background: var(--blue-400);
    color: var(--white);
}

/* Visible, consistent focus for keyboard users */
:focus-visible {
    outline: 2px solid var(--blue-400);
    outline-offset: 3px;
    border-radius: 2px;
}

.skip-link {
    position: absolute;
    left: -9999px;
    top: 0;
    z-index: 200;
    background: var(--navy-700);
    color: var(--white);
    padding: 0.75rem 1.25rem;
    text-decoration: none;
    border-radius: 0 0 var(--radius) 0;
}
.skip-link:focus { left: 0; }

/* ============================================================
   Layout primitives
   ============================================================ */

.container {
    width: 100%;
    max-width: 1140px;
    margin-inline: auto;
    padding-inline: clamp(1.25rem, 5vw, 2.5rem);
}

.container-narrow { max-width: 720px; text-align: center; }

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

.section-light  { background: var(--paper); }
.section-dark   { background: var(--navy-800); color: var(--on-dark); isolation: isolate; }
.section-accent { background: var(--navy-700); color: var(--on-dark); }

.section-eyebrow,
.eyebrow {
    font-family: var(--font-sans);
    font-size: 0.75rem;
    font-weight: 600;
    letter-spacing: 0.16em;
    text-transform: uppercase;
    color: var(--blue-400);
    margin: 0 0 1rem;
}

.section-title {
    font-size: clamp(1.85rem, 1.3rem + 2.4vw, 2.85rem);
    max-width: 22ch;
    margin-bottom: 1.25rem;
}

.section-accent .section-title,
.container-narrow .section-title { max-width: none; }

.container-narrow .section-eyebrow,
.container-narrow .section-title,
.container-narrow .section-intro { margin-inline: auto; }

.section-intro {
    color: var(--ink-muted);
    max-width: 60ch;
    font-size: 1.0625rem;
    margin-bottom: 3rem;
}

.section-dark .section-intro,
.section-accent .section-intro { color: var(--on-dark-muted); }

.prose { max-width: var(--measure); }
.prose .lead {
    font-family: var(--font-serif);
    font-size: clamp(1.3rem, 1.1rem + 0.8vw, 1.6rem);
    line-height: 1.45;
    color: var(--navy-700);
    margin-bottom: 1.5rem;
}
.prose p + p { color: var(--ink-muted); }

/* ============================================================
   Starfield — the cosmic motif, drawn purely in CSS
   ============================================================ */

.starfield {
    position: absolute;
    inset: 0;
    pointer-events: none;
    z-index: -1;
    background-image:
        radial-gradient(1.5px 1.5px at 12% 22%, rgba(255,255,255,0.75), transparent),
        radial-gradient(1px 1px   at 28% 68%, rgba(255,255,255,0.55), transparent),
        radial-gradient(1.5px 1.5px at 45% 15%, rgba(168,208,238,0.7), transparent),
        radial-gradient(1px 1px   at 62% 48%, rgba(255,255,255,0.5),  transparent),
        radial-gradient(2px 2px   at 78% 28%, rgba(255,255,255,0.65), transparent),
        radial-gradient(1px 1px   at 88% 72%, rgba(168,208,238,0.6),  transparent),
        radial-gradient(1px 1px   at 35% 88%, rgba(255,255,255,0.45), transparent),
        radial-gradient(1.5px 1.5px at 70% 82%, rgba(255,255,255,0.5), transparent),
        radial-gradient(1px 1px   at 8%  52%, rgba(255,255,255,0.4),  transparent),
        radial-gradient(1px 1px   at 92% 12%, rgba(255,255,255,0.5),  transparent);
}

.starfield-dim { opacity: 0.5; }

/* ============================================================
   Navigation
   ============================================================ */

.navbar {
    position: sticky;
    top: 0;
    z-index: 100;
    background: rgba(11, 21, 38, 0.85);
    backdrop-filter: blur(12px);
    -webkit-backdrop-filter: blur(12px);
    border-bottom: 1px solid rgba(255, 255, 255, 0.07);
    transition: background 0.3s var(--ease), border-color 0.3s var(--ease);
}

.navbar.is-scrolled {
    background: rgba(11, 21, 38, 0.96);
    border-bottom-color: rgba(255, 255, 255, 0.12);
}

.nav-container {
    max-width: 1140px;
    margin-inline: auto;
    padding: 0.9rem clamp(1.25rem, 5vw, 2.5rem);
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 1.5rem;
}

.logo {
    display: inline-flex;
    align-items: center;
    gap: 0.6rem;
    text-decoration: none;
    color: var(--on-dark);
}

.logo-mark {
    display: grid;
    place-items: center;
    width: 2rem;
    height: 2rem;
    flex: none;
    border: 1px solid var(--blue-400);
    border-radius: 50%;
    font-family: var(--font-serif);
    font-size: 1.15rem;
    line-height: 1;
    color: var(--blue-300);
}

.logo-text {
    font-family: var(--font-serif);
    font-size: 1.3rem;
    letter-spacing: 0.02em;
}

.nav-menu {
    display: flex;
    align-items: center;
    gap: clamp(1.25rem, 3vw, 2.25rem);
    list-style: none;
    margin: 0;
    padding: 0;
}

.nav-link {
    position: relative;
    font-size: 0.9rem;
    font-weight: 500;
    color: var(--on-dark-muted);
    text-decoration: none;
    padding-block: 0.35rem;
    transition: color 0.25s var(--ease);
    white-space: nowrap;
}

.nav-link::after {
    content: '';
    position: absolute;
    left: 0;
    right: 0;
    bottom: 0;
    height: 1px;
    background: var(--blue-400);
    transform: scaleX(0);
    transform-origin: left;
    transition: transform 0.28s var(--ease);
}

.nav-link:hover,
.nav-link.active { color: var(--on-dark); }
.nav-link:hover::after,
.nav-link.active::after { transform: scaleX(1); }

.nav-link-cta {
    border: 1px solid rgba(90, 159, 212, 0.5);
    border-radius: var(--radius);
    padding: 0.45rem 1.05rem;
    color: var(--blue-200);
}
.nav-link-cta::after { display: none; }
.nav-link-cta:hover {
    background: var(--blue-400);
    border-color: var(--blue-400);
    color: var(--navy-900);
}

/* Mobile toggle */
.nav-toggle {
    display: none;
    flex-direction: column;
    justify-content: center;
    gap: 5px;
    width: 2.75rem;
    height: 2.75rem;
    padding: 0;
    background: none;
    border: 1px solid rgba(255, 255, 255, 0.18);
    border-radius: var(--radius);
    cursor: pointer;
}

.nav-toggle-bar {
    display: block;
    width: 18px;
    height: 1.5px;
    margin-inline: auto;
    background: var(--on-dark);
    transition: transform 0.3s var(--ease), opacity 0.2s var(--ease);
}

.nav-toggle[aria-expanded="true"] .nav-toggle-bar:nth-child(1) { transform: translateY(6.5px) rotate(45deg); }
.nav-toggle[aria-expanded="true"] .nav-toggle-bar:nth-child(2) { opacity: 0; }
.nav-toggle[aria-expanded="true"] .nav-toggle-bar:nth-child(3) { transform: translateY(-6.5px) rotate(-45deg); }

/* ============================================================
   Buttons
   ============================================================ */

.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: 0.5rem;
    font-family: var(--font-sans);
    font-size: 0.9rem;
    font-weight: 600;
    letter-spacing: 0.04em;
    line-height: 1;
    padding: 0.95rem 1.9rem;
    border: 1px solid transparent;
    border-radius: var(--radius);
    text-decoration: none;
    cursor: pointer;
    transition: transform 0.2s var(--ease), background-color 0.25s var(--ease),
                border-color 0.25s var(--ease), color 0.25s var(--ease),
                box-shadow 0.25s var(--ease);
}

.btn-lg { padding: 1.1rem 2.5rem; font-size: 0.95rem; }

.btn-primary {
    background: var(--blue-400);
    color: var(--navy-900);
}
.btn-primary:hover {
    background: var(--blue-300);
    transform: translateY(-2px);
    box-shadow: 0 10px 24px -10px rgba(90, 159, 212, 0.8);
}

.btn-ghost {
    border-color: rgba(234, 240, 248, 0.28);
    color: var(--on-dark);
}
.btn-ghost:hover {
    border-color: var(--blue-300);
    color: var(--blue-200);
    transform: translateY(-2px);
}

.btn-outline {
    border-color: var(--navy-600);
    color: var(--navy-700);
    background: transparent;
}
.btn-outline:hover {
    background: var(--navy-700);
    color: var(--white);
    transform: translateY(-2px);
}

/* ============================================================
   Hero
   ============================================================ */

.hero {
    position: relative;
    overflow: hidden;
    background: linear-gradient(165deg, var(--navy-900) 0%, var(--navy-700) 55%, var(--navy-600) 100%);
    color: var(--on-dark);
    padding-block: clamp(4rem, 9vw, 7.5rem);
    isolation: isolate;
}

/* soft light bloom behind the cover */
.hero-glow {
    position: absolute;
    top: 12%;
    right: -5%;
    width: min(46rem, 90vw);
    aspect-ratio: 1;
    border-radius: 50%;
    background: radial-gradient(circle, rgba(90, 159, 212, 0.28) 0%, rgba(90, 159, 212, 0) 68%);
    pointer-events: none;
    z-index: -1;
}

.hero-inner {
    position: relative;
    max-width: 1140px;
    margin-inline: auto;
    padding-inline: clamp(1.25rem, 5vw, 2.5rem);
    display: grid;
    grid-template-columns: 1.15fr 0.85fr;
    gap: clamp(2.5rem, 6vw, 5rem);
    align-items: center;
}

.hero-text { animation: rise 0.9s var(--ease) both; }

.hero-title {
    font-size: clamp(3rem, 1.8rem + 5.6vw, 5.75rem);
    font-weight: 400;
    letter-spacing: -0.02em;
    line-height: 1;
    margin-bottom: 0.5rem;
}

.hero-subtitle {
    font-family: var(--font-serif);
    font-size: clamp(1.2rem, 1rem + 0.9vw, 1.6rem);
    font-style: italic;
    color: var(--blue-200);
    margin-bottom: 2rem;
}

.hero-quote {
    position: relative;
    font-family: var(--font-serif);
    font-size: clamp(1.1rem, 1rem + 0.5vw, 1.35rem);
    line-height: 1.55;
    color: var(--on-dark-muted);
    padding-left: 1.35rem;
    border-left: 2px solid rgba(90, 159, 212, 0.55);
    margin-bottom: 2.5rem;
}

.hero-actions {
    display: flex;
    flex-wrap: wrap;
    gap: 0.9rem;
    margin-bottom: 2.25rem;
}

.hero-meta {
    font-size: 0.85rem;
    letter-spacing: 0.04em;
    color: var(--on-dark-faint);
    margin: 0;
}

.hero-cover {
    display: flex;
    justify-content: center;
    animation: rise 0.9s 0.12s var(--ease) both;
}

.cover-frame {
    position: relative;
    max-width: 22rem;
    width: 100%;
    transform: perspective(1400px) rotateY(-9deg) rotateX(1.5deg);
    transition: transform 0.6s var(--ease);
}

.cover-frame:hover { transform: perspective(1400px) rotateY(-3deg) translateY(-8px); }

.book-cover {
    width: 100%;
    height: auto;
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow-cover);
}

/* the spine highlight down the left edge of the cover */
.cover-frame::before {
    content: '';
    position: absolute;
    top: 0; bottom: 0; left: 0;
    width: 10px;
    border-radius: var(--radius-lg) 0 0 var(--radius-lg);
    background: linear-gradient(to right, rgba(0,0,0,0.32), rgba(255,255,255,0.1));
    z-index: 2;
    pointer-events: none;
}

/* ============================================================
   About
   ============================================================ */

.about-grid {
    display: grid;
    grid-template-columns: 1.6fr 1fr;
    gap: clamp(2rem, 5vw, 4.5rem);
    align-items: start;
}

.about-facts {
    background: var(--white);
    border: 1px solid var(--paper-2);
    border-radius: var(--radius-lg);
    padding: 1.75rem;
    box-shadow: var(--shadow-card);
}

.facts-title {
    font-family: var(--font-sans);
    font-size: 0.72rem;
    font-weight: 600;
    letter-spacing: 0.16em;
    text-transform: uppercase;
    color: var(--ink-faint);
    margin-bottom: 1.25rem;
}

.facts-list { margin: 0; }

.fact {
    display: flex;
    justify-content: space-between;
    align-items: baseline;
    gap: 1rem;
    padding-block: 0.7rem;
    border-top: 1px solid var(--paper-2);
}
.fact:first-child { border-top: none; padding-top: 0; }

.fact dt {
    font-size: 0.82rem;
    color: var(--ink-faint);
    flex: none;
}

.fact dd {
    margin: 0;
    font-weight: 500;
    font-size: 0.92rem;
    color: var(--navy-700);
    text-align: right;
}

/* ============================================================
   Concepts
   ============================================================ */

.concepts-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(min(100%, 17rem), 1fr));
    gap: 1.5rem;
}

.concept {
    position: relative;
    background: rgba(255, 255, 255, 0.035);
    border: 1px solid rgba(255, 255, 255, 0.09);
    border-radius: var(--radius-lg);
    padding: 2rem 1.75rem;
    transition: transform 0.35s var(--ease), border-color 0.35s var(--ease),
                background-color 0.35s var(--ease);
}

.concept:hover {
    transform: translateY(-4px);
    background: rgba(255, 255, 255, 0.06);
    border-color: rgba(90, 159, 212, 0.45);
}

.concept-num {
    font-family: var(--font-serif);
    font-size: 0.95rem;
    letter-spacing: 0.1em;
    color: var(--blue-400);
    margin-bottom: 1.1rem;
}

.concept h3 {
    font-size: 1.35rem;
    color: var(--white);
    margin-bottom: 0.75rem;
}

.concept p {
    font-size: 0.94rem;
    line-height: 1.65;
    color: var(--on-dark-muted);
    margin: 0;
}

/* Epigraph — the book's own dedication line */
.epigraph {
    margin: clamp(3rem, 7vw, 5rem) auto 0;
    max-width: 34rem;
    text-align: center;
}

.epigraph blockquote {
    margin: 0;
    padding-top: 2.25rem;
    border-top: 1px solid rgba(90, 159, 212, 0.3);
}

.epigraph blockquote p {
    font-family: var(--font-serif);
    font-size: clamp(1.25rem, 1.05rem + 0.9vw, 1.7rem);
    font-style: italic;
    line-height: 1.6;
    color: var(--blue-200);
    margin: 0;
}

.epigraph figcaption {
    margin-top: 1.25rem;
    font-size: 0.8rem;
    letter-spacing: 0.12em;
    text-transform: uppercase;
    color: var(--on-dark-faint);
}

/* ============================================================
   Author
   ============================================================ */

.author-grid {
    display: grid;
    grid-template-columns: 17rem 1fr;
    gap: clamp(2rem, 5vw, 4rem);
    align-items: start;
}

.author-portrait { position: relative; }

.author-photo {
    width: 100%;
    aspect-ratio: 4 / 5;
    object-fit: cover;
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow-card);
}

/* Shown only when the photo is missing — see script.js */
.portrait-fallback {
    display: none;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    gap: 0.75rem;
    aspect-ratio: 4 / 5;
    border: 1px dashed rgba(36, 64, 107, 0.3);
    border-radius: var(--radius-lg);
    background: linear-gradient(160deg, var(--paper-2), var(--white));
    text-align: center;
    padding: 1.5rem;
}

.portrait-fallback.is-visible { display: flex; }

.portrait-initials {
    font-family: var(--font-serif);
    font-size: 3rem;
    line-height: 1;
    color: var(--navy-600);
    opacity: 0.5;
}

.portrait-note {
    font-size: 0.78rem;
    letter-spacing: 0.06em;
    text-transform: uppercase;
    color: var(--ink-faint);
}

.bio-note {
    font-size: 0.9rem;
    color: var(--ink-faint);
    padding-top: 0.5rem;
}

/* ============================================================
   Lexicon
   ============================================================ */

.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;
}

.lexicon-tools {
    display: flex;
    flex-wrap: wrap;
    align-items: center;
    gap: 1rem;
    margin-bottom: 1.5rem;
}

.lexicon-search {
    flex: 1 1 20rem;
    max-width: 26rem;
    font-family: inherit;
    font-size: 0.95rem;
    color: var(--ink);
    background: var(--white);
    border: 1px solid #d9dfe9;
    border-radius: var(--radius);
    padding: 0.8rem 1rem;
    transition: border-color 0.25s var(--ease), box-shadow 0.25s var(--ease);
}

.lexicon-search::placeholder { color: var(--ink-faint); }

.lexicon-search:focus {
    outline: none;
    border-color: var(--blue-400);
    box-shadow: 0 0 0 3px rgba(90, 159, 212, 0.18);
}

.lexicon-count {
    font-size: 0.82rem;
    color: var(--ink-faint);
    margin: 0;
}

.lexicon-empty {
    color: var(--ink-faint);
    font-size: 0.9rem;
    margin: 0 0 1.5rem;
}

/* Stage — the rotating card */
.lexicon-stage {
    display: flex;
    flex-direction: column;
    min-width: 0;
}

.lex-track {
    position: relative;
    margin: 0;
    flex: 1;
    background: var(--white);
    border: 1px solid #e3e8f0;
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow-card);
    padding: clamp(1.75rem, 4vw, 2.75rem);
    min-height: 15rem;
    display: flex;
    align-items: center;
}

.term { width: 100%; }

.term dt {
    font-family: var(--font-serif);
    font-size: clamp(1.5rem, 1.2rem + 1.1vw, 2rem);
    line-height: 1.2;
    color: var(--navy-700);
    margin-bottom: 0.9rem;
}

.term dd {
    margin: 0;
    font-size: 1.02rem;
    line-height: 1.7;
    color: var(--ink-muted);
    max-width: 46ch;
}

/* Without JS every term simply stacks and reads normally. */
.js-carousel .term { display: none; }

.js-carousel .term.is-active {
    display: block;
    animation: lexIn 0.45s var(--ease) both;
}

@keyframes lexIn {
    from { opacity: 0; transform: translateY(8px); }
    to   { opacity: 1; transform: none; }
}

.lex-controls {
    display: flex;
    align-items: center;
    gap: 1rem;
    margin-top: 1rem;
}

.lex-btn {
    width: 2.5rem;
    height: 2.5rem;
    flex: none;
    display: grid;
    place-items: center;
    font-size: 1.4rem;
    line-height: 1;
    color: var(--navy-700);
    background: var(--white);
    border: 1px solid #d9dfe9;
    border-radius: 50%;
    cursor: pointer;
    transition: background-color 0.2s var(--ease), border-color 0.2s var(--ease),
                color 0.2s var(--ease);
}

.lex-btn:hover {
    background: var(--navy-700);
    border-color: var(--navy-700);
    color: var(--white);
}

.lex-status {
    margin: 0;
    font-size: 0.8rem;
    letter-spacing: 0.04em;
    color: var(--ink-faint);
}


/* ============================================================
   Buy + Contact
   ============================================================ */

.retailers {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(min(100%, 16rem), 1fr));
    gap: 1.25rem;
    margin-block: 2.5rem 1.75rem;
    text-align: left;
}

.retailer {
    background: rgba(255, 255, 255, 0.05);
    border: 1px solid rgba(255, 255, 255, 0.12);
    border-radius: var(--radius-lg);
    padding: 1.75rem;
}

.retailer-name {
    font-size: 1.3rem;
    color: var(--white);
    margin-bottom: 1.25rem;
}

.retailer-links {
    display: flex;
    flex-direction: column;
    gap: 0.7rem;
}

.retailer-links .btn { width: 100%; }

.buy-actions { margin-block: 2.25rem 1.25rem; }

/* NB: use margin-block, not the `margin` shorthand — the shorthand would
   reset the `margin-inline: auto` that centres these inside .container-narrow. */
.buy-note,
.section-contact .section-intro {
    font-size: 0.88rem;
    color: var(--on-dark-faint);
    margin-block: 0;
    margin-inline: auto;
}

.section-contact .section-intro {
    color: var(--ink-muted);
    margin-bottom: 2.25rem;
}

.contact-address {
    margin-top: 1.5rem;
    font-size: 0.9rem;
    letter-spacing: 0.02em;
    color: var(--ink-faint);
}

/* ============================================================
   Footer
   ============================================================ */

.footer {
    background: var(--navy-900);
    color: var(--on-dark-muted);
    padding-block: 3.5rem 2.5rem;
    border-top: 1px solid rgba(255, 255, 255, 0.07);
}

.footer-inner {
    display: grid;
    gap: 1.75rem;
    justify-items: center;
    text-align: center;
}

.footer-brand {
    display: flex;
    align-items: center;
    gap: 0.85rem;
    text-align: left;
}

.footer-title {
    font-family: var(--font-serif);
    font-size: 1.25rem;
    color: var(--on-dark);
    margin: 0;
}

.footer-sub {
    font-size: 0.82rem;
    color: var(--on-dark-faint);
    margin: 0;
}

.footer-links {
    display: flex;
    flex-wrap: wrap;
    justify-content: center;
    gap: 1.5rem;
}

.footer-links a {
    font-size: 0.88rem;
    color: var(--on-dark-muted);
    text-decoration: none;
    transition: color 0.25s var(--ease);
}
.footer-links a:hover { color: var(--blue-300); }

.footer-copy {
    font-size: 0.8rem;
    color: var(--on-dark-faint);
    margin: 0;
    padding-top: 0.5rem;
    border-top: 1px solid rgba(255, 255, 255, 0.07);
    width: 100%;
    max-width: 34rem;
}

/* ============================================================
   Motion
   ============================================================ */

@keyframes rise {
    from { opacity: 0; transform: translateY(24px); }
    to   { opacity: 1; transform: none; }
}

.reveal {
    opacity: 0;
    transform: translateY(26px);
    transition: opacity 0.7s var(--ease), transform 0.7s var(--ease);
}
.reveal.is-visible { opacity: 1; transform: none; }

/* ============================================================
   Responsive
   ============================================================ */

@media (max-width: 900px) {
    .hero-inner {
        grid-template-columns: 1fr;
        text-align: center;
    }
    .hero-quote {
        border-left: none;
        border-top: 2px solid rgba(90, 159, 212, 0.55);
        padding-left: 0;
        padding-top: 1.25rem;
        max-width: 34ch;
        margin-inline: auto;
    }
    .hero-actions { justify-content: center; }
    .hero-cover { grid-row: 1; }
    .cover-frame { max-width: 16rem; transform: none; }

    .about-grid,
    .author-grid { grid-template-columns: 1fr; }

    .author-portrait { max-width: 15rem; margin-inline: auto; }

    .section-title { max-width: none; }
}

@media (max-width: 720px) {
    .nav-toggle { display: flex; }

    .nav-menu {
        position: absolute;
        top: 100%;
        left: 0;
        right: 0;
        flex-direction: column;
        align-items: stretch;
        gap: 0;
        padding: 0.5rem 1.25rem 1.25rem;
        background: rgba(11, 21, 38, 0.98);
        backdrop-filter: blur(12px);
        -webkit-backdrop-filter: blur(12px);
        border-bottom: 1px solid rgba(255, 255, 255, 0.1);
        /* collapsed by default */
        display: none;
    }

    .nav-menu.is-open { display: flex; }

    .nav-menu .nav-link {
        display: block;
        padding: 0.9rem 0.25rem;
        font-size: 1rem;
        border-bottom: 1px solid rgba(255, 255, 255, 0.06);
    }
    .nav-link::after { display: none; }

    .nav-link-cta {
        margin-top: 0.9rem;
        text-align: center;
        border-bottom: 1px solid rgba(90, 159, 212, 0.5);
    }

    .btn { width: 100%; }
    .hero-actions { flex-direction: column; }
    .buy-actions .btn { width: auto; }
}

@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;
    }
    .reveal { opacity: 1; transform: none; }
    .cover-frame { transform: none; }
}