/* To the Metal — shares the Kronos-Nexus portfolio design language */
:root {
    --ink: #0a0b0d;
    --ink-2: #0d0f12;
    --panel: #131519;
    --panel-2: #181b21;
    --panel-3: #1d212a;
    --line: rgba(255, 255, 255, 0.09);
    --line-strong: rgba(255, 255, 255, 0.16);
    --text: #edeef1;
    --muted: #9096a1;
    --muted-2: #6b7079;
    --accent: #7c8aff;
    --accent-2: #a7b0ff;
    --accent-soft: rgba(124, 138, 255, 0.13);
    --ok: #3fb950;
    --warn: #d0a215;
    --rose: #e06c75;
    /* altitude spine colours */
    --a1: #7c8aff;
    --a2: #56b6c2;
    --a3: #d0a215;
    --a4: #3fb950;
    --radius: 14px;
    --maxw: 780px;
    --ease: cubic-bezier(0.22, 0.61, 0.36, 1);
    --font-display: 'Space Grotesk', system-ui, sans-serif;
    --font-body: 'Inter', system-ui, sans-serif;
    --font-mono: 'JetBrains Mono', ui-monospace, monospace;
}

* { margin: 0; padding: 0; box-sizing: border-box; }
html { scroll-behavior: smooth; -webkit-text-size-adjust: 100%; scroll-padding-top: 90px; }
html, body { overflow-x: hidden; max-width: 100%; }
img, svg { max-width: 100%; height: auto; }

body {
    font-family: var(--font-body);
    background: var(--ink);
    color: var(--text);
    line-height: 1.75;
    -webkit-font-smoothing: antialiased;
    text-rendering: optimizeLegibility;
}
body::before {
    content: ""; position: fixed; inset: 0; pointer-events: none; z-index: -1;
    background:
        radial-gradient(60rem 40rem at 78% -10%, rgba(124, 138, 255, 0.10), transparent 60%),
        radial-gradient(50rem 40rem at -10% 10%, rgba(124, 138, 255, 0.05), transparent 55%);
}
a { color: var(--accent-2); text-decoration: none; transition: color .2s var(--ease); }
a:hover { color: var(--accent); }
::selection { background: rgba(124,138,255,.28); }

/* ---- header ---- */
.site-header {
    position: sticky; top: 0; z-index: 50;
    background: rgba(10, 11, 13, 0.72);
    backdrop-filter: blur(14px);
    border-bottom: 1px solid var(--line);
}
.nav {
    max-width: 1180px; margin: 0 auto; padding: 1rem 1.5rem;
    display: flex; align-items: center; justify-content: space-between; gap: 1rem;
}
.brand {
    font-family: var(--font-display); font-weight: 600; color: var(--text);
    letter-spacing: -.01em; display: inline-flex; align-items: center; gap: .55rem;
}
.brand .dot { width: 8px; height: 8px; border-radius: 50%; background: var(--ok); box-shadow: 0 0 0 3px rgba(63,185,80,.15); }
.brand:hover { color: var(--text); }
.brand .sub { color: var(--muted-2); }
.nav-back { font-family: var(--font-mono); font-size: .82rem; color: var(--muted); }
.nav-back:hover { color: var(--accent-2); }

/* reading progress */
.progress { position: fixed; top: 0; left: 0; height: 2px; width: 0; background: var(--accent); z-index: 60; transition: width .1s linear; }

.wrap { max-width: var(--maxw); margin: 0 auto; padding: 0 1.5rem; }
.eyebrow {
    font-family: var(--font-mono); font-size: .78rem; letter-spacing: .14em;
    text-transform: uppercase; color: var(--accent); margin-bottom: 1rem;
}

/* ---- hero ---- */
.hero { padding: 4.5rem 1.5rem 2.5rem; max-width: var(--maxw); margin: 0 auto; }
.hero h1 {
    font-family: var(--font-display); font-size: clamp(2.1rem, 5.5vw, 3.1rem);
    font-weight: 700; letter-spacing: -.025em; line-height: 1.08; margin-bottom: 1.1rem;
}
.hero .lede { font-size: 1.12rem; color: var(--muted); max-width: 60ch; }
.hero .lede strong { color: var(--text); font-weight: 500; }

.stats { display: flex; gap: 2.2rem; flex-wrap: wrap; margin-top: 2rem; }
.stats div { font-family: var(--font-mono); font-size: .78rem; color: var(--muted-2); letter-spacing: .04em; }
.stats b { display: block; font-family: var(--font-display); font-size: 1.5rem; color: var(--text); font-weight: 600; letter-spacing: -.01em; }

/* ---- phase + day list (index) ---- */
.phase { max-width: var(--maxw); margin: 0 auto; padding: 2.6rem 1.5rem 0; }
.phase-head { display: flex; align-items: baseline; gap: .9rem; border-bottom: 1px solid var(--line); padding-bottom: .7rem; margin-bottom: 1.1rem; }
.phase-head .pn { font-family: var(--font-mono); font-size: .75rem; color: var(--accent); letter-spacing: .1em; }
.phase-head h2 { font-family: var(--font-display); font-size: 1.32rem; font-weight: 600; letter-spacing: -.01em; }
.phase-head .rng { margin-left: auto; font-family: var(--font-mono); font-size: .74rem; color: var(--muted-2); }
.phase > p { color: var(--muted); font-size: .96rem; margin-bottom: 1.2rem; max-width: 62ch; }

.day-row {
    display: flex; gap: 1rem; align-items: flex-start; padding: .85rem 1.1rem;
    border: 1px solid var(--line); border-radius: 11px; margin-bottom: .5rem;
    background: var(--panel); transition: border-color .2s var(--ease), transform .2s var(--ease);
}
a.day-row:hover { border-color: var(--accent); transform: translateX(3px); }
.day-row .dn {
    font-family: var(--font-mono); font-size: .76rem; color: var(--accent);
    flex: none; width: 2.3rem; padding-top: .18rem; letter-spacing: .03em;
}
.day-row .dbody { min-width: 0; flex: 1; }
.day-row h3 { font-family: var(--font-display); font-size: 1.02rem; font-weight: 600; color: var(--text); letter-spacing: -.005em; line-height: 1.35; }
.day-row p { font-size: .9rem; color: var(--muted); margin-top: .18rem; }
.day-row .st { font-family: var(--font-mono); font-size: .68rem; letter-spacing: .08em; text-transform: uppercase; flex: none; padding-top: .35rem; }
.st.live { color: var(--ok); }
.st.soon { color: var(--muted-2); }
.day-row.pending { background: transparent; border-style: dashed; }
.day-row.pending h3 { color: var(--muted); font-weight: 500; }
.day-row.test { border-left: 2px solid var(--warn); }

/* ---- article ---- */
article { max-width: var(--maxw); margin: 0 auto; padding: 0 1.5rem 5rem; }
article h2 {
    font-family: var(--font-display); font-size: 1.62rem; font-weight: 700;
    letter-spacing: -.02em; margin: 3.2rem 0 1rem; line-height: 1.2;
}
article h3 { font-family: var(--font-display); font-size: 1.18rem; font-weight: 600; margin: 2.1rem 0 .7rem; letter-spacing: -.01em; }
article h4 { font-family: var(--font-body); font-size: 1rem; font-weight: 600; color: var(--accent-2); margin: 1.5rem 0 .5rem; }
article p { margin-bottom: 1.05rem; }
article ul, article ol { margin: 0 0 1.15rem 1.3rem; }
article li { margin-bottom: .45rem; }
article strong { color: #fff; font-weight: 600; }
article em { color: var(--accent-2); font-style: italic; }
hr { border: none; border-top: 1px solid var(--line); margin: 2.8rem 0; }

/* altitude section headers — the visual spine */
.alt-head { display: flex; align-items: center; gap: .85rem; margin: 3.4rem 0 1.2rem; }
.alt-head .badge {
    font-family: var(--font-mono); font-size: .68rem; letter-spacing: .1em; text-transform: uppercase;
    padding: .3rem .6rem; border-radius: 6px; flex: none; font-weight: 500;
}
.alt-head h2 { margin: 0; font-size: 1.5rem; }
.alt-1 .badge { background: rgba(124,138,255,.14); color: var(--a1); }
.alt-2 .badge { background: rgba(86,182,194,.14); color: var(--a2); }
.alt-3 .badge { background: rgba(208,162,21,.14); color: var(--a3); }
.alt-4 .badge { background: rgba(63,185,80,.14); color: var(--a4); }
.alt-1 { border-top: 1px solid rgba(124,138,255,.25); padding-top: 2rem; }
.alt-2 { border-top: 1px solid rgba(86,182,194,.25); padding-top: 2rem; }
.alt-3 { border-top: 1px solid rgba(208,162,21,.25); padding-top: 2rem; }
.alt-4 { border-top: 1px solid rgba(63,185,80,.25); padding-top: 2rem; }

/* code */
pre {
    background: var(--ink-2); border: 1px solid var(--line); border-radius: 11px;
    padding: 1.05rem 1.15rem; overflow-x: auto; margin: 0 0 1.3rem;
    font-family: var(--font-mono); font-size: .845rem; line-height: 1.68; color: #d7dae0;
}
pre .c { color: var(--muted-2); font-style: italic; }
pre .k { color: var(--accent-2); }
pre .s { color: #98c379; }
pre .n { color: #d19a66; }
pre .hl { color: var(--warn); }
:not(pre) > code {
    font-family: var(--font-mono); font-size: .855em; background: var(--panel-2);
    border: 1px solid var(--line); border-radius: 5px; padding: .08em .36em; color: var(--accent-2);
}
.codelabel {
    font-family: var(--font-mono); font-size: .67rem; letter-spacing: .1em; text-transform: uppercase;
    color: var(--muted-2); margin-bottom: .35rem;
}

/* tables */
.tw { overflow-x: auto; margin: 0 0 1.4rem; border: 1px solid var(--line); border-radius: 11px; background: var(--panel); }
table { border-collapse: collapse; width: 100%; font-size: .9rem; min-width: 420px; }
th, td { text-align: left; padding: .62rem .9rem; border-bottom: 1px solid var(--line); vertical-align: top; }
th { font-family: var(--font-mono); font-size: .67rem; letter-spacing: .08em; text-transform: uppercase; color: var(--muted); font-weight: 500; background: var(--panel-2); }
tr:last-child td { border-bottom: none; }
td code { white-space: nowrap; }
table.truth { min-width: 0; max-width: 20rem; font-family: var(--font-mono); text-align: center; }
table.truth th, table.truth td { text-align: center; padding: .4rem .7rem; }
table.truth .y { color: var(--ok); font-weight: 600; }

/* callouts */
.note { border-left: 2px solid var(--accent); background: var(--accent-soft); border-radius: 0 11px 11px 0; padding: 1rem 1.2rem; margin: 0 0 1.4rem; }
.note.key { border-left-color: var(--warn); background: rgba(208,162,21,.09); }
.note.trap { border-left-color: var(--rose); background: rgba(224,108,117,.09); }
.note > :last-child { margin-bottom: 0; }
.note .lbl { font-family: var(--font-mono); font-size: .67rem; letter-spacing: .11em; text-transform: uppercase; color: var(--muted); display: block; margin-bottom: .45rem; }

/* worked example blocks */
.ex { border: 1px solid var(--line); border-radius: 11px; background: var(--panel); padding: 1.1rem 1.25rem; margin: 0 0 1.3rem; }
.ex > :last-child { margin-bottom: 0; }
.ex .exn { font-family: var(--font-mono); font-size: .68rem; letter-spacing: .1em; text-transform: uppercase; color: var(--accent); margin-bottom: .55rem; }

/* question / solution */
.q { border: 1px solid var(--line); border-radius: 11px; background: var(--panel); margin-bottom: .6rem; overflow: hidden; }
.q summary { cursor: pointer; padding: .85rem 1.1rem; display: flex; gap: .8rem; align-items: baseline; list-style: none; font-weight: 500; }
.q summary::-webkit-details-marker { display: none; }
.q summary .qn { font-family: var(--font-mono); font-size: .74rem; color: var(--accent); flex: none; }
.q summary::after { content: "reveal"; margin-left: auto; font-family: var(--font-mono); font-size: .66rem; letter-spacing: .08em; text-transform: uppercase; color: var(--muted-2); flex: none; align-self: center; }
.q[open] summary::after { content: "hide"; }
.q[open] summary { border-bottom: 1px solid var(--line); background: var(--panel-2); }
.q .qa { padding: 1rem 1.1rem .4rem; }
.q .qa > :last-child { margin-bottom: 0; }

.prob { border: 1px solid var(--line); border-left: 2px solid var(--accent); border-radius: 0 11px 11px 0; background: var(--panel); padding: 1.15rem 1.3rem; margin: 0 0 1.2rem; }
.prob .ph { display: flex; gap: .7rem; align-items: baseline; margin-bottom: .6rem; flex-wrap: wrap; }
.prob h3 { margin: 0; font-size: 1.08rem; }
.prob .tag { font-family: var(--font-mono); font-size: .66rem; letter-spacing: .07em; text-transform: uppercase; border: 1px solid var(--line-strong); border-radius: 20px; padding: .12rem .55rem; color: var(--muted); }
.prob > :last-child { margin-bottom: 0; }

.pending-sol { border: 1px dashed var(--line-strong); border-radius: 11px; padding: 1.4rem 1.3rem; text-align: center; color: var(--muted); font-size: .93rem; }
.pending-sol .ico { display: block; font-family: var(--font-mono); font-size: .7rem; letter-spacing: .12em; text-transform: uppercase; color: var(--muted-2); margin-bottom: .4rem; }

/* where-to-write */
.paths { font-family: var(--font-mono); font-size: .83rem; }
.paths div { padding: .5rem 0; border-bottom: 1px solid var(--line); display: flex; gap: .9rem; flex-wrap: wrap; }
.paths div:last-child { border-bottom: none; }
.paths .p { color: var(--accent-2); }
.paths .w { color: var(--muted); font-family: var(--font-body); font-size: .88rem; }

/* prev/next */
.pager { max-width: var(--maxw); margin: 0 auto; padding: 0 1.5rem 4rem; display: flex; gap: 1rem; justify-content: space-between; flex-wrap: wrap; }
.pager a, .pager span {
    font-family: var(--font-mono); font-size: .8rem; padding: .75rem 1.1rem;
    border: 1px solid var(--line); border-radius: 10px; background: var(--panel);
}
.pager span { color: var(--muted-2); border-style: dashed; background: transparent; }

/* toc */
.toc { border: 1px solid var(--line); border-radius: 11px; background: var(--panel); padding: 1.05rem 1.25rem; margin: 0 0 2.4rem; }
.toc .lbl { font-family: var(--font-mono); font-size: .67rem; letter-spacing: .11em; text-transform: uppercase; color: var(--muted-2); margin-bottom: .6rem; }
.toc ol { margin: 0 0 0 1.1rem; }
.toc li { margin-bottom: .25rem; font-size: .92rem; }

.site-footer { border-top: 1px solid var(--line); padding: 2rem 1.5rem; text-align: center; color: var(--muted-2); font-size: .85rem; }

@media (max-width: 640px) {
    .hero { padding: 3rem 1.5rem 2rem; }
    .stats { gap: 1.4rem; }
    .day-row { padding: .75rem .9rem; gap: .7rem; }
    .day-row .st { display: none; }
    .alt-head { gap: .6rem; }
    .pager a, .pager span { flex: 1; text-align: center; }
}
@media (prefers-reduced-motion: reduce) { * { transition: none !important; scroll-behavior: auto !important; } }