/* ============================================================
   Furkan Coban — portfolio design system
   Premium / minimal / technical. System type only, no frameworks.
   Signature: mono index + coordinate metadata in margins.
   ============================================================ */

/* ---------- Tokens ---------- */
:root {
  --bg: #fafaf7;
  --surface: #fff;
  --surface-2: #f3f1ec;
  --ink: #141412;
  --muted: #5d6167;
  --faint: #6e7076;
  --line: #e6e2d9;
  --line-soft: #efebe2;
  --accent: #b3400b;
  --accent-ink: #8c3208;
  --accent-soft: rgba(179, 64, 11, .08);
  --ok: #1e7e34;
  --radius-s: 8px;
  --radius-m: 12px;
  --font-sans: -apple-system, BlinkMacSystemFont, "SF Pro Display", "SF Pro Text", "Helvetica Neue", Inter, "Segoe UI", Arial, sans-serif;
  --font-mono: ui-monospace, "SF Mono", "Cascadia Code", Menlo, Consolas, "Liberation Mono", monospace;
  --ease: cubic-bezier(.22, 1, .36, 1);
  --nav-h: 60px;
  --container: 1160px;
  --shadow-soft: 0 1px 2px rgba(20, 20, 18, .05), 0 12px 32px -16px rgba(20, 20, 18, .18);
  color-scheme: light;
}

html[data-theme="dark"] {
  --bg: #131311;
  --surface: #1b1b19;
  --surface-2: #20201d;
  --ink: #ecebe6;
  --muted: #a8a49b;
  --faint: #8f8b82;
  --line: #2b2a26;
  --line-soft: #232320;
  --accent: #e4692a;
  --accent-ink: #f0864f;
  --accent-soft: rgba(228, 105, 42, .13);
  --ok: #4cc38a;
  --shadow-soft: 0 1px 2px rgba(0, 0, 0, .4), 0 16px 40px -16px rgba(0, 0, 0, .55);
  color-scheme: dark;
}

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

html {
  scroll-behavior: smooth;
  -webkit-text-size-adjust: 100%;
}

body {
  margin: 0;
  font-family: var(--font-sans);
  background: var(--bg);
  color: var(--ink);
  font-size: 17px;
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility;
  overflow-x: hidden;
  transition: background-color .3s var(--ease), color .3s var(--ease);
}

h1, h2, h3, h4 { margin: 0; font-weight: 600; letter-spacing: -.03em; line-height: 1.08; text-wrap: balance; }
p, figure { margin: 0; }
a { color: inherit; }
img { max-width: 100%; display: block; }

::selection { background: var(--accent); color: #fff; }

:focus-visible {
  outline: 2px solid var(--accent);
  outline-offset: 3px;
  border-radius: 4px;
}

.container {
  max-width: var(--container);
  margin-inline: auto;
  padding-inline: 24px;
}

.reading { max-width: 68ch; }

.mono { font-family: var(--font-mono); }

.skip-link {
  position: absolute;
  left: 16px;
  top: -48px;
  z-index: 2000;
  background: var(--ink);
  color: var(--bg);
  font-size: 14px;
  padding: 10px 16px;
  border-radius: var(--radius-s);
  text-decoration: none;
  transition: top .2s var(--ease);
}
.skip-link:focus { top: 12px; }

/* ---------- Reveal (already-visible default; subtle transform ease-out) ---------- */
html.js .rv { opacity: 1; transform: translateY(6px); }
html.js .rv.in {
  opacity: 1;
  transform: none;
  transition: transform .32s var(--ease);
  transition-delay: var(--d, 0ms);
}

/* ---------- Navigation ---------- */
.site-nav {
  position: fixed;
  inset: 0 0 auto 0;
  z-index: 1000;
  height: var(--nav-h);
  transition: background-color .25s var(--ease), border-color .25s var(--ease), backdrop-filter .25s var(--ease);
  border-bottom: 1px solid transparent;
}
.site-nav.scrolled {
  background: color-mix(in srgb, var(--bg) 82%, transparent);
  -webkit-backdrop-filter: blur(12px);
  backdrop-filter: blur(12px);
  border-bottom-color: var(--line-soft);
}
.nav-inner {
  height: var(--nav-h);
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
}
.wordmark {
  font-weight: 650;
  font-size: 15.5px;
  letter-spacing: -.015em;
  text-decoration: none;
  white-space: nowrap;
}
.wordmark .wm-suffix { font-family: var(--font-mono); font-weight: 400; font-size: 12.5px; color: var(--faint); margin-left: 6px; }

.nav-links { display: flex; align-items: center; gap: 4px; }
.nav-links a.nav-link {
  font-size: 14.5px;
  font-weight: 500;
  color: var(--muted);
  text-decoration: none;
  padding: 8px 12px;
  border-radius: var(--radius-s);
  position: relative;
  transition: color .18s var(--ease);
}
.nav-links a.nav-link::after {
  content: "";
  position: absolute;
  left: 12px; right: 12px; bottom: 5px;
  height: 1px;
  background: currentColor;
  transform: scaleX(0);
  transform-origin: left;
  transition: transform .22s var(--ease);
}
.nav-links a.nav-link:hover { color: var(--ink); }
.nav-links a.nav-link:hover::after,
.nav-links a.nav-link.active::after { transform: scaleX(1); }
.nav-links a.nav-link.active { color: var(--ink); }

.nav-actions { display: flex; align-items: center; gap: 8px; }

.icon-btn {
  appearance: none;
  border: 1px solid transparent;
  background: transparent;
  color: var(--muted);
  width: 36px; height: 36px;
  display: inline-flex; align-items: center; justify-content: center;
  border-radius: var(--radius-s);
  cursor: pointer;
  transition: color .18s var(--ease), background-color .18s var(--ease), border-color .18s var(--ease);
}
.icon-btn:hover { color: var(--ink); background: var(--accent-soft); }
.icon-btn svg { width: 18px; height: 18px; }

.lang-toggle {
  display: inline-flex;
  font-family: var(--font-mono);
  font-size: 12.5px;
  border: 1px solid var(--line);
  border-radius: var(--radius-s);
  overflow: hidden;
}
.lang-toggle button {
  appearance: none;
  border: 0;
  background: transparent;
  color: var(--faint);
  font: inherit;
  padding: 7px 10px;
  cursor: pointer;
  transition: color .18s var(--ease), background-color .18s var(--ease);
}
.lang-toggle button + button { border-left: 1px solid var(--line); }
.lang-toggle button[aria-pressed="true"] { background: var(--ink); color: var(--bg); }

.btn-cv {
  font-size: 14px;
  font-weight: 550;
  text-decoration: none;
  color: var(--ink);
  border: 1px solid var(--line);
  border-radius: var(--radius-s);
  padding: 8px 14px;
  transition: border-color .18s var(--ease), background-color .18s var(--ease), transform .18s var(--ease);
  white-space: nowrap;
}
.btn-cv:hover { border-color: var(--ink); transform: translateY(-1px); }

.menu-btn { display: none; }

.mobile-menu {
  display: none;
  position: fixed;
  top: var(--nav-h); left: 0; right: 0;
  z-index: 999;
  background: var(--bg);
  border-bottom: 1px solid var(--line);
  padding: 8px 24px 20px;
}
.mobile-menu.open { display: block; }
.mobile-menu a {
  display: block;
  padding: 13px 4px;
  font-size: 17px;
  font-weight: 550;
  letter-spacing: -.01em;
  text-decoration: none;
  border-top: 1px solid var(--line-soft);
}
.mobile-menu a:first-child { border-top: 0; }
.mobile-menu .mm-meta {
  font-family: var(--font-mono);
  font-size: 12.5px;
  color: var(--faint);
  padding-top: 12px;
}

/* ---------- Hero ---------- */
.hero { padding: calc(var(--nav-h) + 72px) 0 0; }

.hero-top-meta {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 10px 16px;
  font-family: var(--font-mono);
  font-size: 12.5px;
  letter-spacing: .02em;
  color: var(--faint);
  margin-bottom: 32px;
}
.availability {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  color: var(--muted);
  border: 1px solid var(--line);
  background: var(--surface);
  border-radius: 999px;
  padding: 6px 13px 6px 11px;
  font-size: 12.5px;
}
.availability .dot {
  width: 7px; height: 7px;
  border-radius: 50%;
  background: var(--ok);
  box-shadow: 0 0 0 3px color-mix(in srgb, var(--ok) 18%, transparent);
  flex-shrink: 0;
}

.hero-grid {
  display: grid;
  grid-template-columns: minmax(0, 1fr) 256px;
  gap: 48px;
  align-items: center;
}

.hero-name {
  font-size: clamp(3.75rem, 8vw, 7.5rem);
  letter-spacing: -.045em;
  font-weight: 650;
}
.hero-role {
  margin-top: 20px;
  font-size: clamp(1.15rem, 2.2vw, 1.5rem);
  font-weight: 550;
  letter-spacing: -.02em;
}
.hero-role .sep { color: var(--faint); font-weight: 400; margin: 0 10px; }
.hero-lede {
  margin-top: 18px;
  font-size: 17.5px;
  line-height: 1.62;
  color: var(--muted);
  max-width: 58ch;
}
.hero-lede strong { color: var(--ink); font-weight: 600; }

.hero-cta { display: flex; flex-wrap: wrap; align-items: center; gap: 12px 20px; margin-top: 32px; }

.btn-primary {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  background: var(--ink);
  color: var(--bg);
  font-size: 15px;
  font-weight: 550;
  text-decoration: none;
  padding: 12px 20px;
  border-radius: 10px;
  border: 1px solid var(--ink);
  transition: transform .18s var(--ease), opacity .18s var(--ease);
}
.btn-primary:hover { transform: translateY(-1px); opacity: .92; }
.btn-primary svg { width: 15px; height: 15px; transition: transform .2s var(--ease); }
.btn-primary:hover svg { transform: translate(2px, -2px); }

.alink {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  font-size: 15px;
  font-weight: 550;
  text-decoration: none;
  background-image: linear-gradient(currentColor, currentColor);
  background-size: 100% 1px;
  background-position: 0 100%;
  background-repeat: no-repeat;
  padding-bottom: 2px;
  transition: color .18s var(--ease);
}
.alink svg { width: 14px; height: 14px; transition: transform .2s var(--ease); }
.alink:hover { color: var(--accent-ink); }
html[data-theme="dark"] .alink:hover { color: var(--accent); }
.alink:hover svg { transform: translate(3px, -3px); }

.hero-meta {
  display: flex;
  flex-wrap: wrap;
  gap: 8px 20px;
  margin-top: 40px;
  padding-top: 20px;
  border-top: 1px solid var(--line-soft);
  font-family: var(--font-mono);
  font-size: 12.5px;
  color: var(--faint);
}
.hero-meta a { color: var(--muted); text-decoration: none; }
.hero-meta a:hover { color: var(--ink); text-decoration: underline; text-underline-offset: 3px; }

.portrait {
  margin: 0;
  justify-self: end;
  display: flex;
  flex-direction: column;
  align-items: center;
  width: 236px;
}
.portrait img {
  width: 236px;
  height: 236px;
  aspect-ratio: 1 / 1;
  max-width: none;
  object-fit: cover;
  object-position: 50% 22%;
  border-radius: 50%;
  border: 2px solid var(--line);
  box-shadow: var(--shadow-soft);
  filter: saturate(.92);
  flex-shrink: 0;
  transition: transform .3s var(--ease), filter .3s var(--ease), border-color .3s var(--ease);
}
.portrait img:hover { transform: scale(1.018); filter: saturate(1); border-color: var(--muted); }
.portrait figcaption {
  margin-top: 14px;
  font-family: var(--font-mono);
  font-size: 11.5px;
  color: var(--faint);
  text-align: center;
  line-height: 1.45;
}

/* ---------- Sections ---------- */
.section { padding: 104px 0 0; }
.section:last-of-type { padding-bottom: 24px; }

.sec-head {
  display: flex;
  align-items: baseline;
  gap: 14px;
  margin-bottom: 40px;
}
.sec-index {
  font-family: var(--font-mono);
  font-size: 13px;
  color: var(--accent);
  font-weight: 500;
}
.sec-title {
  font-size: clamp(2rem, 4vw, 3rem);
  letter-spacing: -.035em;
  font-weight: 650;
  white-space: nowrap;
}
.sec-rule { flex: 1; height: 1px; background: var(--line); align-self: center; min-width: 24px; }
.sec-meta {
  font-family: var(--font-mono);
  font-size: 12.5px;
  color: var(--faint);
  white-space: nowrap;
}

/* ---------- Work ---------- */
.feature {
  display: grid;
  grid-template-columns: minmax(0, 5fr) minmax(0, 7fr);
  gap: 48px;
  padding: 40px 0 48px;
  border-top: 1px solid var(--line);
}
.feature-head { display: flex; align-items: center; gap: 12px; margin-bottom: 18px; }
.proj-no { font-family: var(--font-mono); font-size: 13px; color: var(--faint); }
.status {
  font-family: var(--font-mono);
  font-size: 11.5px;
  letter-spacing: .06em;
  text-transform: uppercase;
  color: var(--ok);
  border: 1px solid color-mix(in srgb, var(--ok) 40%, transparent);
  border-radius: 999px;
  padding: 4px 11px;
  background: color-mix(in srgb, var(--ok) 8%, transparent);
}
.status.proto { color: var(--muted); border-color: var(--line); background: transparent; }
.proj-title { font-size: clamp(1.6rem, 2.6vw, 2.1rem); letter-spacing: -.03em; font-weight: 650; }
.proj-purpose { margin-top: 10px; font-size: 16.5px; font-weight: 550; letter-spacing: -.01em; }
.proj-body { margin-top: 12px; color: var(--muted); font-size: 16px; line-height: 1.62; }
.proj-facts {
  margin-top: 22px;
  display: grid;
  grid-template-columns: auto 1fr;
  gap: 7px 18px;
  font-size: 14px;
}
.proj-facts dt { font-family: var(--font-mono); font-size: 12.5px; color: var(--faint); padding-top: 2px; white-space: nowrap; }
.proj-facts dd { margin: 0; }
.proj-facts dd.stack { font-family: var(--font-mono); font-size: 13px; color: var(--muted); line-height: 1.7; }
.proj-links { display: flex; flex-wrap: wrap; gap: 8px 22px; margin-top: 24px; }

.sys-panel {
  background: var(--surface);
  border: 1px solid var(--line);
  border-radius: var(--radius-m);
  box-shadow: var(--shadow-soft);
  overflow: hidden;
  align-self: start;
}
.sys-panel-head {
  display: flex;
  justify-content: space-between;
  gap: 12px;
  padding: 12px 18px;
  border-bottom: 1px solid var(--line-soft);
  font-family: var(--font-mono);
  font-size: 12px;
  color: var(--faint);
}
.sys-flow { padding: 22px 18px 14px; display: flex; flex-direction: column; }
.sys-node {
  border: 1px solid var(--line);
  border-radius: var(--radius-s);
  padding: 10px 14px;
  font-family: var(--font-mono);
  font-size: 12.5px;
  line-height: 1.5;
  background: var(--bg);
}
.sys-node b { font-weight: 600; color: var(--ink); }
.sys-node span { color: var(--faint); }
.sys-arrow { color: var(--faint); font-family: var(--font-mono); font-size: 12px; padding: 5px 0 5px 14px; }
.sys-note {
  padding: 14px 18px 18px;
  font-family: var(--font-mono);
  font-size: 12px;
  color: var(--faint);
  border-top: 1px dashed var(--line);
  margin-top: 12px;
  line-height: 1.7;
}
.sys-note a { color: var(--accent-ink); }
html[data-theme="dark"] .sys-note a { color: var(--accent); }

.proj-row {
  display: grid;
  grid-template-columns: 56px minmax(0, 1fr) auto;
  gap: 20px;
  align-items: baseline;
  padding: 28px 0;
  border-top: 1px solid var(--line);
}
.proj-row:last-child { border-bottom: 1px solid var(--line); }
.proj-row h3 { font-size: 1.35rem; letter-spacing: -.025em; font-weight: 600; }
.proj-row .row-desc { margin-top: 8px; color: var(--muted); font-size: 15.5px; max-width: 62ch; }
.proj-row .row-stack { margin-top: 10px; font-family: var(--font-mono); font-size: 12.5px; color: var(--faint); }
.row-side { text-align: right; display: flex; flex-direction: column; gap: 10px; align-items: flex-end; }
.row-year { font-family: var(--font-mono); font-size: 12.5px; color: var(--faint); white-space: nowrap; }

/* ---------- Experience ---------- */
.exp-block { border-top: 1px solid var(--line); padding: 8px 0 40px; }
.exp-group-label {
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: .08em;
  text-transform: uppercase;
  color: var(--faint);
  padding: 24px 0 4px;
}
.exp-row {
  display: grid;
  grid-template-columns: 150px minmax(0, 1fr);
  gap: 24px;
  padding: 20px 0;
  border-bottom: 1px solid var(--line-soft);
}
.exp-row:last-child { border-bottom: 0; }
.exp-year { font-family: var(--font-mono); font-size: 13px; color: var(--muted); padding-top: 3px; white-space: nowrap; }
.exp-role { font-size: 16.5px; font-weight: 600; letter-spacing: -.015em; }
.exp-org { margin-top: 2px; font-size: 15px; color: var(--muted); }
.exp-org a { color: inherit; text-decoration: underline; text-decoration-color: var(--line); text-underline-offset: 3px; }
.exp-org a:hover { color: var(--accent-ink); }
.exp-detail { margin-top: 8px; font-size: 15px; color: var(--muted); max-width: 66ch; }
.exp-note { margin-top: 6px; font-family: var(--font-mono); font-size: 12.5px; color: var(--faint); }

/* ---------- About / skills ---------- */
.about-grid { display: grid; grid-template-columns: minmax(0, 7fr) minmax(0, 5fr); gap: 56px; }
.about-copy p { color: var(--muted); font-size: 17px; line-height: 1.65; }
.about-copy p + p { margin-top: 16px; }
.about-copy strong { color: var(--ink); font-weight: 600; }
.stack-groups { border-top: 1px solid var(--line); }
.stack-group { padding: 18px 0; border-bottom: 1px solid var(--line-soft); }
.stack-group h3 {
  font-family: var(--font-mono);
  font-size: 12px;
  font-weight: 500;
  letter-spacing: .08em;
  text-transform: uppercase;
  color: var(--faint);
  margin-bottom: 8px;
}
.stack-group p { font-size: 15.5px; line-height: 1.65; }
.stack-group p + p { margin-top: 12px; }
.oss-tag {
  display: inline-block;
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: .04em;
  text-transform: uppercase;
  padding: 2px 8px;
  border-radius: 999px;
  margin-left: 6px;
  vertical-align: middle;
  border: 1px solid var(--line);
  color: var(--muted);
}
.oss-tag.merged {
  color: var(--ok);
  border-color: color-mix(in srgb, var(--ok) 45%, transparent);
  background: color-mix(in srgb, var(--ok) 10%, transparent);
}

/* ---------- Contact ---------- */
.contact-wrap { border-top: 1px solid var(--line); padding-top: 40px; }
.contact-big {
  font-size: clamp(1.9rem, 4.4vw, 3.2rem);
  letter-spacing: -.035em;
  font-weight: 650;
  max-width: 20ch;
}
.contact-sub { margin-top: 16px; color: var(--muted); font-size: 17px; max-width: 56ch; }
.email-line { margin-top: 28px; }
.email-big {
  font-size: clamp(1.15rem, 2.6vw, 1.7rem);
  font-weight: 600;
  letter-spacing: -.02em;
  text-decoration: none;
  background-image: linear-gradient(var(--accent), var(--accent));
  background-size: 100% 2px;
  background-position: 0 100%;
  background-repeat: no-repeat;
  padding-bottom: 4px;
  transition: color .18s var(--ease);
}
.email-big:hover { color: var(--accent-ink); }
html[data-theme="dark"] .email-big:hover { color: var(--accent); }
.contact-rows {
  margin-top: 32px;
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 24px;
  border-top: 1px solid var(--line-soft);
  padding-top: 24px;
}
.contact-cell h3 {
  font-family: var(--font-mono);
  font-size: 12px;
  font-weight: 500;
  letter-spacing: .08em;
  text-transform: uppercase;
  color: var(--faint);
  margin-bottom: 10px;
}
.contact-cell a, .contact-cell span.val { font-size: 15.5px; font-weight: 550; text-decoration: none; display: inline-flex; align-items: center; gap: 6px; }
.contact-cell a:hover { color: var(--accent-ink); }
.contact-cell a svg { width: 13px; height: 13px; transition: transform .2s var(--ease); }
.contact-cell a:hover svg { transform: translate(2px, -2px); }
.contact-cell .sub { display: block; margin-top: 4px; font-size: 13.5px; color: var(--faint); font-weight: 400; }

/* ---------- Footer ---------- */
.site-footer { margin-top: 112px; border-top: 1px solid var(--line); }
.footer-inner {
  display: flex;
  flex-wrap: wrap;
  align-items: baseline;
  justify-content: space-between;
  gap: 12px 24px;
  padding: 28px 0 36px;
  font-family: var(--font-mono);
  font-size: 12.5px;
  color: var(--faint);
}
.footer-inner a { color: var(--muted); text-decoration: none; }
.footer-inner a:hover { color: var(--ink); text-decoration: underline; text-underline-offset: 3px; }
.footer-links { display: flex; gap: 20px; }

/* ---------- CV viewer / stub pages ---------- */
.cv-page { min-height: 100vh; display: flex; flex-direction: column; }
.cv-bar {
  display: flex; align-items: center; justify-content: space-between; gap: 12px;
  padding: 12px 20px;
  border-bottom: 1px solid var(--line);
  background: var(--surface);
  position: sticky; top: 0; z-index: 10;
}
.cv-bar h1 { font-size: 15px; letter-spacing: -.01em; }
.cv-bar .row { display: flex; gap: 10px; }
.cv-frame { flex: 1; display: flex; flex-direction: column; }
.cv-frame iframe { width: 100%; height: calc(100vh - 62px); border: 0; background: #fff; }
.stub { padding: 120px 0 80px; }
.stub .mono { color: var(--faint); font-size: 13px; }

/* ---------- Responsive ---------- */
@media (max-width: 900px) {
  .hero-grid { grid-template-columns: 1fr; }
  .portrait { justify-self: start; align-items: flex-start; width: auto; margin: 12px 0 0; }
  .portrait img { width: 156px; height: 156px; aspect-ratio: 1 / 1; }
  .portrait figcaption { text-align: left; }
  .feature { grid-template-columns: 1fr; gap: 32px; }
  .about-grid { grid-template-columns: 1fr; gap: 40px; }
  .contact-rows { grid-template-columns: 1fr; gap: 20px; }
  .nav-links { display: none; }
  .menu-btn { display: inline-flex; }
  .btn-cv { display: none; }
  .sec-meta { display: none; }
  .sec-title { white-space: normal; }
}

@media (max-width: 640px) {
  body { font-size: 16px; }
  .section { padding-top: 76px; }
  .hero { padding-top: calc(var(--nav-h) + 44px); }
  .hero-top-meta { margin-bottom: 24px; }
  .hero-meta { margin-top: 28px; }
  .exp-row { grid-template-columns: 1fr; gap: 6px; }
  .exp-year { padding-top: 0; }
  .proj-row { grid-template-columns: 1fr; gap: 8px; }
  .row-side { text-align: left; align-items: flex-start; flex-direction: row; gap: 16px; }
  .site-footer { margin-top: 80px; }
}

/* ---------- Motion preferences ---------- */
@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  *, *::before, *::after { transition-duration: .01ms !important; animation-duration: .01ms !important; }
  html.js .rv { opacity: 1; transform: none; }
}