/* ==========================================================================
   Gradient Key — Studio
   Cool daylight. A composed scroll of deliberate "rooms," hung off a single
   drafting-sheet margin rule and anchored left, with open field to the right.
   The studio sells by being exact and well-made, not by claiming.
   ========================================================================== */

/* 1. Type — Inter Tight, self-hosted. One variable woff2 (latin) carries the
   whole 400/500 weight discipline; no third-party font host in the chain.
   ========================================================================== */
@font-face {
    font-family: 'Inter Tight';
    font-style: normal;
    font-weight: 400 500;
    font-display: swap;
    src: url('/fonts/inter-tight-v9-latin.woff2') format('woff2');
    unicode-range: U+0000-00FF, U+0131, U+0152-0153, U+02BB-02BC, U+02C6, U+02DA, U+02DC, U+0304, U+0308, U+0329, U+2000-206F, U+20AC, U+2122, U+2191, U+2193, U+2212, U+2215, U+FEFF, U+FFFD;
}

/* 2. Tokens (BRAND.md §5–§6, §8). Change the brand from one place.
   ========================================================================== */
:root {
    /* Color — Cool Daylight */
    --page:          #F1F3F3;
    --surface:       #FFFFFF;
    --surface-2:     #E6EAEB;
    --ink-primary:   #16181A;
    --ink-secondary: #545C63;
    --ink-tertiary:  #8A9298;
    --line:          #DDE3E4;
    --line-strong:   #C7CFD1;
    --accent:        #3B5680;   /* mature slate-blue */
    --accent-hover:  #2F4768;
    --accent-bg:     #E9EDF4;
    --focus:         rgba(59, 86, 128, 0.5);

    /* Typography — neo-grotesque, carried by the setting */
    --font-sans: 'Inter Tight', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;

    /* Motion — architectural; things settle into position */
    --ease-arch: cubic-bezier(0.4, 0, 0.2, 1);
    --t-hover: 180ms;
    --t-settle: 360ms;

    /* Field & rhythm */
    --pad: clamp(1.5rem, 5vw, 4rem);      /* container side padding */
    --max: 1600px;                         /* outer cap; layout is LEFT-anchored, never centered */
    --rail: clamp(2.25rem, 4vw, 3.25rem);  /* narrow margin column → the sequence number */
    --gutter: clamp(1rem, 2.5vw, 1.75rem); /* spine → content */
    --content: clamp(54rem, 64vw, 66rem);  /* body measure: grows with viewport so the right field stays bounded */
    --room-y: clamp(3.75rem, 9vw, 7rem);   /* vertical room rhythm */
    --radius: 10px;
}

/* 3. Reset & base
   ========================================================================== */
*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }

html { background-color: var(--page); scroll-behavior: smooth; }

body {
    background-color: var(--page);
    color: var(--ink-primary);
    font-family: var(--font-sans);
    font-size: 16px;
    line-height: 1.55;
    font-feature-settings: 'tnum' 1;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
    min-height: 100svh;
}

::selection { background: var(--accent-bg); }
a { color: inherit; text-decoration: none; }
:focus-visible { outline: 2px solid var(--focus); outline-offset: 4px; border-radius: 2px; }

/* Left-anchored at every width: the left edge stays put, the open field is on
   the right. Never centers (which is what made the body drift back on wide screens). */
.container { width: 100%; max-width: var(--max); margin-right: auto; padding-inline: var(--pad); }

/* 4. Masthead — a quiet persistent lockup; one CTA; no section nav (anti-agency)
   ========================================================================== */
.masthead { border-bottom: 1px solid var(--line); }
.masthead .container {
    display: flex;
    align-items: center;
    justify-content: space-between;
    min-height: 4.5rem;
    gap: 1rem;
}
.lockup { display: inline-flex; align-items: center; gap: 0.6rem; }
.lockup__mark { width: 22px; height: 22px; display: block; }
.lockup__word { font-size: 1.02rem; font-weight: 500; letter-spacing: -0.01em; color: var(--ink-primary); }
.lockup__word .key { color: var(--accent); }
.masthead__cta {
    font-size: 0.9rem;
    font-weight: 500;
    color: var(--accent);
    position: relative;
    padding-bottom: 0.2rem;
    transition: color var(--t-hover) var(--ease-arch);
}
.masthead__cta::after {
    content: '';
    position: absolute; left: 0; bottom: 0;
    width: 100%; height: 1px;
    background: var(--accent);
    transform: scaleX(0); transform-origin: left;
    transition: transform var(--t-settle) var(--ease-arch);
}
.masthead__cta:hover { color: var(--accent-hover); }
.masthead__cta:hover::after { transform: scaleX(1); }

/* 5. The sheet — rooms anchored left, hung off a continuous spine
   ========================================================================== */
.sheet { position: relative; }
/* The spine: one hairline running the full length of the rooms, near the left. */
.sheet::before {
    content: '';
    position: absolute;
    top: 0;
    bottom: 0;
    left: calc(var(--pad) + var(--rail));
    width: 1px;
    background: var(--line);
}

.room {
    position: relative;
    padding: var(--room-y) 0 var(--room-y) calc(var(--rail) + var(--gutter));
    max-width: calc(var(--rail) + var(--gutter) + var(--content));
}
.room + .room { border-top: 1px solid var(--line); }

/* Sequence number in the narrow margin, right-aligned toward the spine. */
.room__seq {
    position: absolute;
    left: 0;
    top: calc(var(--room-y) + 0.15rem);
    width: var(--rail);
    padding-right: var(--gutter);
    text-align: right;
    font-size: 0.8rem;
    font-weight: 500;
    color: var(--accent);
}

/* Section descriptor, as a quiet eyebrow above the heading. */
.room__eyebrow {
    font-size: 0.72rem;
    font-weight: 500;
    letter-spacing: 0.12em;
    text-transform: uppercase;
    color: var(--ink-tertiary);
    margin-bottom: 0.9rem;
}

/* 6. Opening room
   ========================================================================== */
.open { animation: settle var(--t-settle) var(--ease-arch) both; }
.open__mark { display: block; width: 46px; height: 46px; margin-bottom: 1.75rem; }
.wordmark {
    font-size: clamp(2.5rem, 6.5vw, 4.4rem);
    font-weight: 500;
    line-height: 1.02;
    letter-spacing: -0.01em;
    color: var(--ink-primary);
}
.wordmark .key { color: var(--accent); }
.open__line {
    margin-top: 1.35rem;
    font-size: clamp(1.05rem, 1.8vw, 1.25rem);
    font-weight: 400;
    color: var(--ink-primary);
}
.open__lede {
    margin-top: 0.9rem;
    max-width: 46ch;
    font-size: 1.02rem;
    color: var(--ink-secondary);
}
.open__actions { margin-top: 2.1rem; }

/* 7. Headings & shared text
   ========================================================================== */
.room__head {
    font-size: clamp(1.5rem, 3vw, 2.15rem);
    font-weight: 500;
    line-height: 1.12;
    letter-spacing: -0.005em;
    margin-bottom: 1.6rem;
}
.lede {
    max-width: 56ch;
    font-size: 1.04rem;
    color: var(--ink-secondary);
    margin-bottom: 2.4rem;
}

/* 8. "What we do" — two prose rooms, wider columns
   ========================================================================== */
.duo {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: clamp(2rem, 4.5vw, 3.5rem);
}
.mode__kind {
    font-size: 0.72rem;
    font-weight: 500;
    letter-spacing: 0.1em;
    text-transform: uppercase;
    color: var(--accent);
    margin-bottom: 0.7rem;
}
.mode__title { font-size: 1.2rem; font-weight: 500; margin-bottom: 0.6rem; }
.mode__body { font-size: 0.99rem; color: var(--ink-secondary); }
.mode__eg { margin-top: 0.9rem; font-size: 0.9rem; color: var(--ink-tertiary); line-height: 1.5; }

/* 9. "How we work" — plain statements; the trust room
   ========================================================================== */
.points { display: grid; gap: 1.5rem; }
.point { display: grid; gap: 0.3rem; }
.point__title { font-size: 1.04rem; font-weight: 500; color: var(--ink-primary); }
.point__body { font-size: 0.97rem; color: var(--ink-secondary); max-width: 60ch; }

/* 10. Engage room
   ========================================================================== */
.engage__email {
    display: inline-block;
    margin-top: 0.4rem;
    font-size: clamp(1.35rem, 3vw, 1.9rem);
    font-weight: 500;
    letter-spacing: -0.01em;
    color: var(--ink-primary);
    position: relative;
    padding-bottom: 0.25rem;
    transition: color var(--t-hover) var(--ease-arch);
}
.engage__email::after {
    content: '';
    position: absolute; left: 0; bottom: 0;
    width: 100%; height: 1px;
    background: var(--accent);
    transform: scaleX(0); transform-origin: left;
    transition: transform var(--t-settle) var(--ease-arch);
}
.engage__email:hover { color: var(--accent); }
.engage__email:hover::after { transform: scaleX(1); }
.engage__attribution { margin-top: 2.4rem; font-size: 0.85rem; color: var(--ink-tertiary); }
.engage__attribution a { color: var(--ink-secondary); transition: color var(--t-hover) var(--ease-arch); }
.engage__attribution a:hover { color: var(--accent); }

/* 11. Button — one confident primary action; it settles, it does not perform
   ========================================================================== */
.btn {
    display: inline-flex;
    align-items: center;
    background: var(--accent);
    color: #fff;
    font-weight: 500;
    font-size: 0.95rem;
    padding: 0.7rem 1.2rem;
    border-radius: var(--radius);
    transition: background var(--t-hover) var(--ease-arch);
}
.btn:hover { background: var(--accent-hover); }

/* 12. Footer — GK's own colophon: left-aligned, sentence case (not Steelmark's
   corner title-block). Until a cross-brand title-block is a real decision,
   GK does not borrow the parent's drafting annotations.
   ========================================================================== */
.foot { border-top: 1px solid var(--line); }
.foot .container { padding-block: 1.75rem 2.5rem; }
.foot__line { font-size: 0.82rem; color: var(--ink-tertiary); }

/* 13. Motion
   ========================================================================== */
@keyframes settle {
    from { opacity: 0; transform: translateY(8px); }
    to   { opacity: 1; transform: translateY(0); }
}
@media (prefers-reduced-motion: reduce) {
    html { scroll-behavior: auto; }
    .open { animation: none; }
    .masthead__cta, .masthead__cta::after, .engage__email, .engage__email::after,
    .engage__attribution a, .btn { transition: none; }
}

/* 14. Responsive — the spine retires; the sequence number becomes inline
   ========================================================================== */
@media (max-width: 720px) {
    .sheet::before { display: none; }
    .room { padding-left: 0; max-width: none; }
    .room__seq {
        position: static;
        width: auto;
        padding-right: 0;
        text-align: left;
        margin-bottom: 0.5rem;
    }
    .duo { grid-template-columns: 1fr; gap: 2rem; }
}