/* ============================================================
   Unknot Digital — clean & techy
   Charcoal + electric blue, dotted engineering paper.
   ============================================================ */
:root {
  --bg: #111315;
  --bg-2: #1B1E21;
  --bg-3: #24282C;
  --paper: #F3F4F1;
  --white: #FFFFFF;
  --ink: #111315;
  --grey: #9AA1A6;
  --grey-2: #5C6368;
  --line: rgba(255, 255, 255, .12);
  --blue: #4D8DFF;
  --blue-dark: #1F5FD6;
  --font-head: "Space Grotesk", system-ui, sans-serif;
  --font-body: "Inter", system-ui, sans-serif;
  --font-mono: "JetBrains Mono", ui-monospace, monospace;
  --radius: 14px;
}

* { box-sizing: border-box; }
[hidden] { display: none !important; }
html { scroll-behavior: smooth; }
body { margin: 0; font-family: var(--font-body); color: var(--ink); background: var(--paper); line-height: 1.6; }
h1, h2, h3 { font-family: var(--font-head); line-height: 1.1; letter-spacing: -.02em; margin: 0 0 .5em; }
h1 { font-size: clamp(2.6rem, 6vw, 4.6rem); }
h2 { font-size: clamp(1.9rem, 3.6vw, 2.8rem); }
h3 { font-size: 1.35rem; }
a { color: inherit; }
img { max-width: 100%; display: block; }
.container { width: min(1120px, 100% - 32px); margin-inline: auto; }

/* Engineering paper backgrounds */
.dots-dark { background-color: var(--bg); background-image: radial-gradient(rgba(255,255,255,.09) 1px, transparent 1.2px); background-size: 22px 22px; }
.dots-light { background-color: var(--paper); background-image: radial-gradient(rgba(17,19,21,.13) 1px, transparent 1.2px); background-size: 22px 22px; }

/* Small mono labels */
.label { font: 700 .78rem var(--font-mono); letter-spacing: .14em; text-transform: uppercase; color: var(--grey-2); margin: 0 0 1rem; }
.label b { color: var(--blue-dark); }
.dark .label { color: var(--grey); }
.dark .label b { color: var(--blue); }
.hero .label, .page-head .label { color: var(--grey); }
.hero .label b, .page-head .label b { color: var(--blue); }

/* Buttons */
.btn {
  display: inline-flex; align-items: center; gap: .5em; background: var(--blue); color: var(--white);
  border: 0; border-radius: 10px; padding: .9em 1.35em; font: 600 1rem/1 var(--font-body); text-decoration: none; cursor: pointer;
  transition: transform .15s, background .15s;
}
.btn:hover { background: #3B7BF0; transform: translateY(-1px); }
.btn-ghost { background: transparent; color: var(--white); box-shadow: inset 0 0 0 1.5px rgba(255,255,255,.35); }
.btn-ghost:hover { background: rgba(255,255,255,.08); }
.btn-small { padding: .65em 1em; font-size: .9rem; }

/* Nav */
.nav { position: sticky; top: 0; z-index: 20; background: rgba(17,19,21,.88); backdrop-filter: blur(10px); color: var(--white); border-bottom: 1px solid var(--line); }
.nav-inner { display: flex; align-items: center; justify-content: space-between; gap: 16px; padding: 14px 0; }
.logo { display: flex; align-items: center; gap: 10px; text-decoration: none; font: 700 1.35rem/1 var(--font-head); letter-spacing: -.02em; }
.logo svg { width: 30px; height: 30px; }
.logo small { font: 500 .7rem var(--font-mono); color: var(--grey); letter-spacing: .1em; text-transform: uppercase; margin-left: 2px; }
.nav-links { display: flex; align-items: center; gap: 26px; }
.nav-links a:not(.btn) { text-decoration: none; font-size: .95rem; color: #D6DADD; white-space: nowrap; }
.nav-links .sm { display: none; }
.nav-links a:not(.btn):hover, .nav-links a[aria-current="page"] { color: var(--white); }
.nav-links a[aria-current="page"] { text-decoration: underline; text-decoration-color: var(--blue); text-underline-offset: 6px; }

/* Hero */
.hero { color: var(--white); padding: 72px 0 88px; overflow: hidden; }
.hero-inner { display: grid; grid-template-columns: 1.1fr .9fr; gap: 40px; align-items: center; }
.hero-inner > * { min-width: 0; }
.hero h1 { margin-bottom: .35em; }
.hero h1 em { font-style: normal; color: var(--blue); }
.lead { font-size: 1.18rem; color: #C9CED2; max-width: 560px; }
.hero-actions { display: flex; flex-wrap: wrap; gap: 12px; margin-top: 28px; }
.creds { display: flex; flex-wrap: wrap; gap: 8px 18px; margin-top: 34px; padding-top: 22px; border-top: 1px solid var(--line); font: 500 .8rem var(--font-mono); color: var(--grey); }
.creds span::before { content: "▸ "; color: var(--blue); }

/* Interactive knot (drawn on a canvas by script.js) */
.knot-box { position: relative; user-select: none; -webkit-user-select: none; }
.knot-canvas { display: block; width: 100%; aspect-ratio: 400 / 380; touch-action: pan-y; cursor: ew-resize; }
.knot-label { display: flex; justify-content: space-between; gap: 12px; margin: 0 0 4px; font: 600 .7rem var(--font-mono); letter-spacing: .12em; color: var(--grey); }
.knot-status { color: var(--grey); transition: color .3s; }
.knot-status.solved { color: var(--blue); }
.knot-control { display: grid; grid-template-columns: auto 1fr auto; align-items: center; gap: 12px; margin-top: 8px; font: 700 .7rem var(--font-mono); letter-spacing: .14em; color: var(--grey); text-transform: uppercase; }
.knot-control input { width: 100%; accent-color: var(--blue); cursor: pointer; }
.knot-hint { margin: 10px 0 0; text-align: center; font: 500 .75rem var(--font-mono); color: var(--grey); letter-spacing: .06em; }
.knot-hint::before { content: "↔ "; color: var(--blue); }

/* Sections */
.section { padding: 96px 0; }
.dark { background: var(--bg); color: var(--white); }
.section-head { max-width: 640px; margin-bottom: 44px; }
.section-head p { color: var(--grey-2); font-size: 1.08rem; margin: 0; }
.dark .section-head p { color: #B8BEC2; }

/* Sound familiar? */
.tangles { list-style: none; padding: 0; margin: 0; display: grid; grid-template-columns: repeat(auto-fit, minmax(240px, 1fr)); gap: 14px; }
.tangles li { background: var(--white); border-radius: var(--radius); padding: 20px 22px 20px 52px; position: relative; font-weight: 500; box-shadow: 0 1px 0 rgba(17,19,21,.06); }
.tangles li::before {
  content: ""; position: absolute; left: 20px; top: 24px; width: 18px; height: 14px;
  background: no-repeat center/contain url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 24 18'%3E%3Cpath d='M2 12C5 12 6 3 10 3s4 7 0 7-2 6 3 6h9' fill='none' stroke='%231F5FD6' stroke-width='2.4' stroke-linecap='round'/%3E%3C/svg%3E");
}

/* Services */
.services { display: grid; grid-template-columns: repeat(3, 1fr); gap: 20px; }
.service { background: var(--bg-2); border: 1px solid var(--line); border-radius: var(--radius); padding: 30px 28px; position: relative; overflow: hidden; }
.service::after { content: ""; position: absolute; left: 0; right: 0; top: 0; height: 3px; background: var(--blue); transform: scaleX(.18); transform-origin: left; transition: transform .35s; }
.service:hover::after { transform: scaleX(1); }
.service .num { font: 700 .95rem var(--font-mono); color: var(--blue); }
.service h3 { margin: 14px 0 6px; }
.service > p { color: #B8BEC2; margin: 0 0 18px; }
.service ul { list-style: none; margin: 0; padding: 18px 0 0; border-top: 1px dashed var(--line); display: grid; gap: 8px; font-size: .95rem; color: #DDE1E4; }
.service li::before { content: "→ "; color: var(--blue); font-family: var(--font-mono); }

/* Process */
.steps { list-style: none; padding: 0; margin: 0; display: grid; grid-template-columns: repeat(4, 1fr); gap: 0; position: relative; }
.steps::before { content: ""; position: absolute; left: 0; right: 0; top: 13px; border-top: 2px dashed rgba(17,19,21,.18); }
.steps li { position: relative; padding: 44px 22px 0 0; }
.steps li::before { content: ""; position: absolute; left: 0; top: 4px; width: 20px; height: 20px; border-radius: 50%; background: var(--paper); border: 3px solid var(--blue-dark); }
.steps .num { font: 700 .8rem var(--font-mono); color: var(--blue-dark); letter-spacing: .1em; }
.steps h3 { margin: 6px 0 6px; font-size: 1.25rem; }
.steps p { margin: 0; color: var(--grey-2); font-size: .97rem; }

/* Projects */
.project-grid { display: grid; grid-template-columns: repeat(auto-fill, minmax(330px, 1fr)); gap: 24px; }
.project-grid[data-limit="2"] { grid-template-columns: repeat(2, 1fr); }
.project { background: var(--white); border-radius: var(--radius); overflow: hidden; display: flex; flex-direction: column; box-shadow: 0 1px 0 rgba(17,19,21,.06), 0 12px 32px rgba(17,19,21,.07); }
.project-shot { position: relative; aspect-ratio: 16 / 10; background: var(--bg-2); overflow: hidden; border-bottom: 1px solid rgba(17,19,21,.08); }
.project-shot img { width: 100%; height: 100%; object-fit: cover; object-position: top; transition: transform .5s; }
.project:hover .project-shot img { transform: scale(1.03); }
.project-shot .placeholder { position: absolute; inset: 0; display: grid; place-items: center; color: var(--grey); font: 500 .85rem var(--font-mono); }
.browser-bar { position: absolute; left: 0; right: 0; top: 0; height: 22px; background: rgba(17,19,21,.85); display: flex; align-items: center; gap: 5px; padding: 0 10px; z-index: 1; }
.browser-bar i { width: 7px; height: 7px; border-radius: 50%; background: rgba(255,255,255,.3); }
.project-shot:has(.browser-bar) img { padding-top: 22px; }
.project-body { padding: 22px 24px 24px; display: flex; flex-direction: column; gap: 12px; flex: 1; }
.project-meta { display: flex; flex-wrap: wrap; gap: 6px 10px; align-items: center; font: 700 .72rem var(--font-mono); letter-spacing: .1em; text-transform: uppercase; color: var(--grey-2); }
.tag { color: var(--blue-dark); background: #E7EFFF; border-radius: 6px; padding: 3px 8px; }
.sample { color: #9a4128; border: 1.5px dashed #E07A5F; border-radius: 6px; padding: 2px 7px; }
.project h3 { margin: 0; font-size: 1.4rem; }
.project .client { margin: -6px 0 0; color: var(--grey-2); font-size: .95rem; }
.project dl { margin: 0; display: grid; gap: 10px; }
.project dt { font: 700 .72rem var(--font-mono); letter-spacing: .12em; text-transform: uppercase; color: var(--blue-dark); }
.project dd { margin: 2px 0 0; color: #33393E; font-size: .97rem; }
.project .links { margin-top: auto; padding-top: 14px; border-top: 1px dashed rgba(17,19,21,.14); display: flex; flex-direction: column; align-items: flex-start; gap: 8px; font-size: .9rem; }
.project .links a { font-weight: 600; color: var(--blue-dark); text-decoration: none; }
.project .links a:hover { text-decoration: underline; }
.project .links .soon { font: 500 .78rem var(--font-mono); color: var(--grey-2); }
.filters { display: flex; flex-wrap: wrap; gap: 8px; margin-bottom: 28px; }
.chip { border: 1.5px solid var(--ink); background: transparent; color: var(--ink); padding: 7px 14px; border-radius: 999px; font: 600 .88rem var(--font-body); cursor: pointer; }
.chip.active { background: var(--ink); color: var(--white); }
.see-all { margin-top: 32px; }

/* About */
.about { display: grid; grid-template-columns: 340px 1fr; gap: 56px; align-items: center; }
.about-photo { position: relative; border-radius: 18px; overflow: hidden; aspect-ratio: 4 / 5; box-shadow: 0 20px 50px rgba(0,0,0,.35); }
.about-photo img { width: 100%; height: 100%; object-fit: cover; }
.about-photo::after { content: "FIG. 2 — THE ENGINEER"; position: absolute; left: 12px; bottom: 12px; font: 600 .68rem var(--font-mono); letter-spacing: .12em; background: rgba(17,19,21,.75); color: #E9ECEE; padding: 5px 8px; border-radius: 6px; }
.about p { color: #C9CED2; font-size: 1.05rem; }
.facts { list-style: none; padding: 0; margin: 26px 0 0; display: grid; grid-template-columns: 1fr 1fr; gap: 12px; }
.facts li { border: 1px solid var(--line); border-radius: 12px; padding: 14px 16px; background: var(--bg-2); }
.facts small { display: block; font: 700 .68rem var(--font-mono); letter-spacing: .12em; text-transform: uppercase; color: var(--blue); margin-bottom: 4px; }

/* Contact */
.contact { text-align: center; }
.contact h2 { font-size: clamp(2.2rem, 5vw, 3.6rem); }
.contact p { color: #C9CED2; font-size: 1.12rem; max-width: 560px; margin: 0 auto 30px; }
.contact-links { display: flex; flex-wrap: wrap; justify-content: center; gap: 12px; }

/* Free resources */
.resource-grid { display: grid; grid-template-columns: repeat(auto-fill, minmax(320px, 1fr)); gap: 20px; }
.resource-card {
  display: flex; flex-direction: column; gap: 10px; background: var(--white); border-radius: var(--radius); padding: 26px;
  text-decoration: none; color: inherit; border-top: 3px solid var(--blue); box-shadow: 0 1px 0 rgba(17,19,21,.06), 0 12px 32px rgba(17,19,21,.07);
  transition: transform .15s;
}
.resource-card:hover { transform: translateY(-3px); }
.resource-card h3 { margin: 4px 0 0; font-size: 1.35rem; }
.resource-card p { margin: 0; color: var(--grey-2); flex: 1; }
.resource-card .read { font-weight: 600; color: var(--blue-dark); }
.prose { max-width: 760px; font-size: 1.06rem; }
.prose h2 { font-size: 1.6rem; margin: 1.6em 0 .5em; }
.prose h2:first-child { margin-top: 0; }
.prose li { margin: 6px 0; }
.prose a { color: var(--blue-dark); }
.checklist { list-style: none; padding: 0; }
.checklist label { display: flex; gap: 12px; align-items: flex-start; background: var(--white); border-radius: 10px; padding: 12px 14px; cursor: pointer; }
.checklist input { width: 18px; height: 18px; margin-top: 3px; accent-color: var(--blue-dark); flex: none; }
.checklist input:checked + span { color: var(--grey-2); text-decoration: line-through; }
code.prompt, .prompt-block code { font: 500 .9em var(--font-mono); background: #E7EFFF; color: #12306E; border-radius: 6px; padding: 2px 6px; }
.prompt-block { position: relative; background: var(--bg); border-radius: 12px; padding: 18px 20px 18px; margin: 0 0 1em; }
.prompt-block code { display: block; background: none; color: #E9ECEE; padding: 0 70px 0 0; line-height: 1.6; white-space: pre-wrap; }
.prompt-block .copy { position: absolute; top: 12px; right: 12px; border: 1px solid var(--line); background: var(--bg-2); color: var(--white); border-radius: 8px; padding: 6px 10px; font: 600 .78rem var(--font-body); cursor: pointer; }
.prompt-block .copy:hover { border-color: var(--blue); }
.resource-actions { display: flex; flex-wrap: wrap; gap: 12px; margin-top: 40px; max-width: 760px; }
.btn-dark { background: var(--ink); }
.btn-dark:hover { background: #2A2E33; }
.btn-outline { background: transparent; color: var(--ink); box-shadow: inset 0 0 0 1.5px var(--ink); }
.btn-outline:hover { background: rgba(17,19,21,.06); }
@media print {
  .nav, .footer, .resource-actions, .section.dark, .prompt-block .copy { display: none !important; }
  .page-head, .dots-dark, .dots-light { background: none !important; color: var(--ink) !important; padding: 0 0 12px; }
  .page-head p, .page-head .label { color: var(--grey-2) !important; }
  .section { padding: 0; }
  .prompt-block { background: #f1f1f1; }
  .prompt-block code { color: var(--ink); }
}

/* Contact form */
.contact-grid { display: grid; grid-template-columns: .9fr 1.1fr; gap: 56px; align-items: start; }
.contact-intro p { color: #C9CED2; font-size: 1.08rem; }
.contact-alt a { color: var(--blue); }
.contact-form { background: var(--bg-2); border: 1px solid var(--line); border-radius: var(--radius); padding: 28px; display: grid; gap: 16px; }
.contact-form .row { display: grid; grid-template-columns: 1fr 1fr; gap: 16px; }
.contact-form label { display: grid; gap: 6px; font: 700 .72rem var(--font-mono); letter-spacing: .12em; text-transform: uppercase; color: var(--grey); }
.contact-form input, .contact-form select, .contact-form textarea {
  font: 400 1rem var(--font-body); color: var(--white); background: var(--bg); border: 1px solid var(--line); border-radius: 10px;
  padding: 12px 14px; text-transform: none; letter-spacing: 0; width: 100%;
}
.contact-form textarea { resize: vertical; min-height: 120px; }
.contact-form input:focus, .contact-form select:focus, .contact-form textarea:focus { outline: 2px solid var(--blue); outline-offset: 1px; border-color: transparent; }
.contact-form .btn { justify-self: start; }
.contact-form .hp { position: absolute; left: -9999px; }
.form-status { margin: 0; min-height: 1.4em; font-size: .95rem; color: #C9CED2; }
.form-status.ok { color: #7FD69B; }
.form-status.error { color: #FF8A7A; }
.form-status a { color: inherit; }

/* Page header (sub-pages) */
.page-head { color: var(--white); padding: 72px 0 64px; }
.page-head p { color: #C9CED2; font-size: 1.12rem; max-width: 620px; margin: 0; }

/* Footer */
.footer { background: var(--bg); color: var(--grey); border-top: 1px solid var(--line); padding: 28px 0; font-size: .9rem; }
.footer-inner { display: flex; justify-content: space-between; flex-wrap: wrap; gap: 10px; }
.footer a { color: #D6DADD; text-decoration: none; }
.footer a:hover { color: var(--white); }

/* Phones */
@media (max-width: 860px) {
  .nav-links { gap: 12px; }
  .nav-links a:not(.btn) { font-size: .82rem; }
  .nav-links .btn, .nav-links .lg { display: none; }
  .nav-links .sm { display: inline; }
  .logo { font-size: 1.15rem; gap: 8px; }
  .logo svg { width: 26px; height: 26px; }
  .logo small { font-size: .6rem; }
  .hero { padding: 48px 0 64px; }
  .hero-inner, .about, .contact-grid { grid-template-columns: 1fr; gap: 28px; }
  .contact-form .row { grid-template-columns: 1fr; }
  .knot-box { max-width: 400px; margin: 0 auto; width: 100%; }
  .services { grid-template-columns: 1fr; }
  .steps { grid-template-columns: 1fr 1fr; row-gap: 32px; }
  .steps::before { display: none; }
  .about-photo { max-width: 320px; }
  .facts { grid-template-columns: 1fr; }
  .section { padding: 72px 0; }
  .project-grid, .project-grid[data-limit="2"] { grid-template-columns: 1fr; }
}



/* Very small phones: keep logo, grey "digital" and menu on one line */
@media (max-width: 400px) {
  .nav-links { gap: 10px; }
  .nav-links a:not(.btn) { font-size: .78rem; }
  .logo { font-size: 1.05rem; gap: 6px; }
  .logo small { letter-spacing: .05em; margin-left: 0; }
}