/* ============================================================
   Samet Kocak — Personal Site
   Style: Motion-Driven · Monochrome + blue accent · Inter
   ============================================================ */

/* ---------- Design Tokens ---------- */
:root {
  --color-accent: #2563eb;
  --color-accent-hover: #1d4ed8;
  --color-on-accent: #ffffff;

  /* Light theme (default) */
  --bg: #fafafa;
  --bg-elevated: #ffffff;
  --bg-muted: #f1f3f6;
  --fg: #09090b;
  --fg-soft: #3f3f46;
  --fg-muted: #71717a;
  --border: #e4e4e7;
  --ring: rgba(37, 99, 235, 0.4);
  --shadow-sm: 0 1px 2px rgba(9, 9, 11, 0.06), 0 1px 3px rgba(9, 9, 11, 0.04);
  --shadow-md: 0 4px 12px rgba(9, 9, 11, 0.08), 0 2px 4px rgba(9, 9, 11, 0.05);
  --shadow-lg: 0 16px 40px rgba(9, 9, 11, 0.12);
  --code-bg: #18181b;
  --code-fg: #e4e4e7;
  --nav-bg: rgba(250, 250, 250, 0.72);

  /* Spacing scale (8pt) */
  --sp-1: 0.25rem; --sp-2: 0.5rem; --sp-3: 0.75rem; --sp-4: 1rem;
  --sp-6: 1.5rem; --sp-8: 2rem; --sp-12: 3rem; --sp-16: 4rem; --sp-24: 6rem;

  --radius-sm: 8px;
  --radius: 14px;
  --radius-lg: 20px;

  --container: 1120px;
  --nav-h: 68px;

  --ease-out: cubic-bezier(0.22, 1, 0.36, 1);
  --t-fast: 160ms;
  --t-base: 280ms;
}

[data-theme="dark"] {
  --bg: #09090b;
  --bg-elevated: #18181b;
  --bg-muted: #131316;
  --fg: #fafafa;
  --fg-soft: #d4d4d8;
  --fg-muted: #a1a1aa;
  --border: #27272a;
  --ring: rgba(59, 130, 246, 0.5);
  --shadow-sm: 0 1px 2px rgba(0, 0, 0, 0.4);
  --shadow-md: 0 4px 16px rgba(0, 0, 0, 0.45);
  --shadow-lg: 0 20px 50px rgba(0, 0, 0, 0.6);
  --code-bg: #131316;
  --code-fg: #e4e4e7;
  --nav-bg: rgba(9, 9, 11, 0.72);
  --color-accent: #3b82f6;
  --color-accent-hover: #60a5fa;
}

/* ---------- Reset & Base ---------- */
*, *::before, *::after { box-sizing: border-box; }
* { margin: 0; }

html { scroll-behavior: smooth; scroll-padding-top: calc(var(--nav-h) + 16px); }

body {
  font-family: 'Inter', system-ui, -apple-system, sans-serif;
  background: var(--bg);
  color: var(--fg);
  line-height: 1.65;
  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility;
  transition: background var(--t-base) var(--ease-out), color var(--t-base) var(--ease-out);
  overflow-x: hidden;
}

h1, h2, h3 { line-height: 1.15; letter-spacing: -0.02em; font-weight: 700; }
a { color: inherit; text-decoration: none; }
img, svg { display: block; }
button { font: inherit; cursor: pointer; }

.icon { width: 22px; height: 22px; }
.icon--sm { width: 18px; height: 18px; }

.text-accent { color: var(--color-accent); }

.container {
  width: 100%;
  max-width: var(--container);
  margin-inline: auto;
  padding-inline: var(--sp-6);
}

.section { padding-block: var(--sp-24); }
.section--muted { background: var(--bg-muted); }

.skip-link {
  position: absolute; left: -999px; top: 0;
  background: var(--color-accent); color: #fff;
  padding: var(--sp-2) var(--sp-4); border-radius: 0 0 var(--radius-sm) 0;
  z-index: 1000;
}
.skip-link:focus { left: 0; }

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

/* ---------- Section heads ---------- */
.section__head { max-width: 640px; margin-bottom: var(--sp-12); }
.section__kicker {
  display: inline-block; font-size: 0.8rem; font-weight: 600;
  letter-spacing: 0.08em; text-transform: uppercase;
  color: var(--color-accent); margin-bottom: var(--sp-3);
}
.section__title { font-size: clamp(1.8rem, 4vw, 2.6rem); }
.section__sub { margin-top: var(--sp-4); color: var(--fg-muted); font-size: 1.05rem; }

/* ---------- Buttons ---------- */
.btn {
  display: inline-flex; align-items: center; justify-content: center;
  gap: var(--sp-2);
  padding: 0.8rem 1.4rem; border-radius: var(--radius-sm);
  font-weight: 600; font-size: 0.96rem; border: 1px solid transparent;
  transition: transform var(--t-fast) var(--ease-out),
              background var(--t-fast) var(--ease-out),
              border-color var(--t-fast) var(--ease-out),
              box-shadow var(--t-fast) var(--ease-out);
  white-space: nowrap;
}
.btn:active { transform: scale(0.97); }
.btn--primary { background: var(--color-accent); color: var(--color-on-accent); box-shadow: var(--shadow-sm); }
.btn--primary:hover { background: var(--color-accent-hover); box-shadow: var(--shadow-md); transform: translateY(-1px); }
.btn--ghost { background: transparent; color: var(--fg); border-color: var(--border); }
.btn--ghost:hover { border-color: var(--fg-muted); background: var(--bg-elevated); }
.btn--full { width: 100%; }
.btn .icon { transition: transform var(--t-fast) var(--ease-out); }
.btn--primary:hover .icon { transform: translateX(3px); }

/* ---------- Nav ---------- */
.nav {
  position: fixed; inset: 0 0 auto 0; z-index: 100;
  height: var(--nav-h);
  background: var(--nav-bg);
  backdrop-filter: saturate(180%) blur(14px);
  -webkit-backdrop-filter: saturate(180%) blur(14px);
  border-bottom: 1px solid transparent;
  transition: border-color var(--t-base) var(--ease-out), background var(--t-base) var(--ease-out);
}
.nav.is-scrolled { border-bottom-color: var(--border); }
.nav__inner { display: flex; align-items: center; justify-content: space-between; height: var(--nav-h); }
.nav__brand { display: inline-flex; align-items: center; gap: var(--sp-3); color: var(--fg); }
.nav__logo { height: 30px; width: auto; transition: transform var(--t-fast) var(--ease-out); }
.nav__brand:hover .nav__logo { transform: scale(1.06); }
.nav__brand-text { font-size: 1.08rem; font-weight: 700; letter-spacing: -0.02em; }
.nav__links { display: flex; gap: var(--sp-2); }
.nav__link {
  position: relative; padding: var(--sp-2) var(--sp-3);
  font-size: 0.94rem; font-weight: 500; color: var(--fg-soft);
  border-radius: var(--radius-sm); transition: color var(--t-fast) var(--ease-out);
}
.nav__link::after {
  content: ''; position: absolute; left: var(--sp-3); right: var(--sp-3); bottom: 6px;
  height: 2px; background: var(--color-accent); border-radius: 2px;
  transform: scaleX(0); transform-origin: left; transition: transform var(--t-fast) var(--ease-out);
}
.nav__link:hover { color: var(--fg); }
.nav__link.is-active { color: var(--fg); }
.nav__link.is-active::after { transform: scaleX(1); }
.nav__actions { display: flex; align-items: center; gap: var(--sp-2); }

.icon-btn {
  display: inline-grid; place-items: center;
  width: 42px; height: 42px; border-radius: var(--radius-sm);
  background: transparent; border: 1px solid var(--border); color: var(--fg);
  transition: background var(--t-fast) var(--ease-out), border-color var(--t-fast) var(--ease-out), transform var(--t-fast) var(--ease-out);
}
.icon-btn:hover { background: var(--bg-elevated); border-color: var(--fg-muted); }
.icon-btn:active { transform: scale(0.94); }
.nav__burger { display: none; }

.icon-moon { display: none; }
[data-theme="dark"] .icon-sun { display: none; }
[data-theme="dark"] .icon-moon { display: block; }

/* Mobile menu */
.mobile-menu {
  display: flex; flex-direction: column;
  padding: var(--sp-2) var(--sp-6) var(--sp-6);
  background: var(--bg-elevated); border-bottom: 1px solid var(--border);
  gap: var(--sp-1);
}
.mobile-menu[hidden] { display: none; }
.mobile-menu__link {
  padding: var(--sp-3) var(--sp-2); font-weight: 500; color: var(--fg-soft);
  border-radius: var(--radius-sm);
}
.mobile-menu__link:hover { background: var(--bg-muted); color: var(--fg); }

/* ---------- Hero ---------- */
.hero { padding-top: calc(var(--nav-h) + var(--sp-24)); position: relative; overflow: hidden; }
.hero::before {
  content: ''; position: absolute; top: -20%; right: -10%;
  width: 50vw; height: 50vw; max-width: 640px; max-height: 640px;
  background: radial-gradient(circle, rgba(37, 99, 235, 0.16), transparent 65%);
  pointer-events: none; z-index: 0;
}
.hero__inner {
  position: relative; z-index: 1;
  display: grid; grid-template-columns: 1.1fr 0.9fr; gap: var(--sp-16); align-items: center;
}
.hero__eyebrow {
  display: inline-flex; align-items: center; gap: var(--sp-2);
  font-size: 0.86rem; font-weight: 500; color: var(--fg-muted);
  padding: 0.4rem 0.85rem; border: 1px solid var(--border); border-radius: 999px;
  background: var(--bg-elevated); margin-bottom: var(--sp-6);
}
.status-dot {
  width: 8px; height: 8px; border-radius: 50%; background: #22c55e;
  box-shadow: 0 0 0 0 rgba(34, 197, 94, 0.5); animation: pulse 2.4s infinite;
}
@keyframes pulse {
  0% { box-shadow: 0 0 0 0 rgba(34, 197, 94, 0.5); }
  70% { box-shadow: 0 0 0 8px rgba(34, 197, 94, 0); }
  100% { box-shadow: 0 0 0 0 rgba(34, 197, 94, 0); }
}
.hero__title { font-size: clamp(2.2rem, 6vw, 3.6rem); font-weight: 800; }
.hero__lead { margin-top: var(--sp-6); font-size: 1.12rem; color: var(--fg-soft); max-width: 38ch; }
.hero__actions { margin-top: var(--sp-8); display: flex; gap: var(--sp-3); flex-wrap: wrap; }
.hero__socials { list-style: none; padding: 0; display: flex; gap: var(--sp-3); margin-top: var(--sp-8); }
.social-link {
  display: inline-grid; place-items: center; width: 44px; height: 44px;
  border: 1px solid var(--border); border-radius: var(--radius-sm); color: var(--fg-soft);
  transition: color var(--t-fast) var(--ease-out), border-color var(--t-fast) var(--ease-out), transform var(--t-fast) var(--ease-out);
}
.social-link:hover { color: var(--color-accent); border-color: var(--color-accent); transform: translateY(-2px); }
.social-link .icon { width: 20px; height: 20px; }

/* Hero code visual */
.hero__visual { display: flex; justify-content: center; }
/* Circular frame: accent gradient disc that clips the portrait inside it */
.hero__photo {
  position: relative; width: min(380px, 82%); aspect-ratio: 1; margin: 0;
  border-radius: 50%; overflow: hidden;
  background: radial-gradient(circle at 50% 30%, var(--color-accent), #1e3a8a 72%);
  box-shadow: var(--shadow-lg), 0 0 0 1px var(--border);
}
/* Subtle inner highlight ring on top of the photo */
.hero__photo::after {
  content: ''; position: absolute; inset: 0; border-radius: 50%;
  box-shadow: inset 0 0 0 1px rgba(255, 255, 255, 0.14); pointer-events: none;
}
.hero__photo img {
  position: absolute; inset: 0;
  width: 100%; height: 100%;
  object-fit: cover; object-position: center top;
}

/* ---------- About ---------- */
.about { display: grid; grid-template-columns: 1.4fr 1fr; gap: var(--sp-16); align-items: start; }
.about__text p { color: var(--fg-soft); font-size: 1.08rem; }
.about__text p + p { margin-top: var(--sp-4); }
.about__stats { display: grid; gap: var(--sp-4); }
.stat {
  display: flex; align-items: baseline; flex-wrap: wrap;
  padding: var(--sp-6); background: var(--bg-elevated);
  border: 1px solid var(--border); border-radius: var(--radius);
  box-shadow: var(--shadow-sm);
}
.stat__num { font-size: 2.4rem; font-weight: 800; line-height: 1; font-variant-numeric: tabular-nums; }
.stat__plus { font-size: 2.4rem; font-weight: 800; color: var(--color-accent); }
.stat__label { width: 100%; margin-top: var(--sp-2); color: var(--fg-muted); font-size: 0.92rem; }

/* ---------- Skills ---------- */
.skills { display: grid; grid-template-columns: repeat(2, 1fr); gap: var(--sp-6); }
.skill-card {
  padding: var(--sp-8); background: var(--bg-elevated);
  border: 1px solid var(--border); border-radius: var(--radius-lg);
  box-shadow: var(--shadow-sm);
  transition: transform var(--t-base) var(--ease-out), box-shadow var(--t-base) var(--ease-out), border-color var(--t-base) var(--ease-out);
}
.skill-card:hover { transform: translateY(-4px); box-shadow: var(--shadow-lg); border-color: color-mix(in srgb, var(--color-accent) 40%, var(--border)); }
.skill-card__icon {
  display: inline-grid; place-items: center; width: 52px; height: 52px;
  border-radius: var(--radius); margin-bottom: var(--sp-4);
  background: color-mix(in srgb, var(--color-accent) 12%, transparent);
  color: var(--color-accent);
}
.skill-card__title { font-size: 1.25rem; margin-bottom: var(--sp-4); }
.skill-card__list { list-style: none; padding: 0; display: grid; gap: var(--sp-2); }
.skill-card__list li {
  position: relative; padding-left: var(--sp-6); color: var(--fg-soft); font-size: 0.98rem;
}
.skill-card__list li::before {
  content: ''; position: absolute; left: 0; top: 0.6em;
  width: 7px; height: 7px; border-radius: 2px; background: var(--color-accent);
}

/* ---------- Timeline ---------- */
.timeline { list-style: none; padding: 0; position: relative; max-width: 760px; }
.timeline::before {
  content: ''; position: absolute; left: 7px; top: 6px; bottom: 6px;
  width: 2px; background: var(--border);
}
.timeline__item { position: relative; padding-left: var(--sp-12); padding-bottom: var(--sp-8); }
.timeline__item:last-child { padding-bottom: 0; }
.timeline__marker {
  position: absolute; left: 0; top: 6px; width: 16px; height: 16px;
  border-radius: 50%; background: var(--bg); border: 3px solid var(--color-accent);
  z-index: 1;
}
.timeline__card {
  padding: var(--sp-6); background: var(--bg-elevated);
  border: 1px solid var(--border); border-radius: var(--radius);
  box-shadow: var(--shadow-sm);
  transition: transform var(--t-base) var(--ease-out), box-shadow var(--t-base) var(--ease-out);
}
.timeline__card:hover { transform: translateX(4px); box-shadow: var(--shadow-md); }
.timeline__head { display: flex; justify-content: space-between; align-items: baseline; gap: var(--sp-4); flex-wrap: wrap; }
.timeline__role { font-size: 1.18rem; }
.timeline__date {
  font-size: 0.82rem; font-weight: 600; color: var(--color-accent);
  font-variant-numeric: tabular-nums; white-space: nowrap;
}
.timeline__company { color: var(--fg-muted); font-weight: 500; margin-top: var(--sp-1); }
.timeline__desc { margin-top: var(--sp-3); color: var(--fg-soft); }

/* ---------- Contact ---------- */
.contact { display: grid; grid-template-columns: 1.2fr 0.8fr; gap: var(--sp-12); align-items: start; }
.field { margin-bottom: var(--sp-4); }
.field label { display: block; font-weight: 500; font-size: 0.92rem; margin-bottom: var(--sp-2); }
.req { color: var(--color-accent); }
.field input, .field textarea {
  width: 100%; padding: 0.8rem 0.95rem; font: inherit;
  background: var(--bg-elevated); color: var(--fg);
  border: 1px solid var(--border); border-radius: var(--radius-sm);
  transition: border-color var(--t-fast) var(--ease-out), box-shadow var(--t-fast) var(--ease-out);
  resize: vertical; min-height: 48px;
}
.field input:focus, .field textarea:focus {
  outline: none; border-color: var(--color-accent); box-shadow: 0 0 0 3px var(--ring);
}
.field.has-error input, .field.has-error textarea { border-color: #dc2626; }
.field__error { min-height: 1.1em; margin-top: var(--sp-1); font-size: 0.82rem; color: #dc2626; }
.form-status { margin-top: var(--sp-3); font-size: 0.92rem; font-weight: 500; min-height: 1.2em; }
.form-status.is-success { color: #16a34a; }
.form-status.is-error { color: #dc2626; }

.btn__spinner { display: none; animation: spin 0.7s linear infinite; }
.btn.is-loading .btn__spinner { display: block; }
.btn.is-loading { pointer-events: none; opacity: 0.85; }
@keyframes spin { to { transform: rotate(360deg); } }

.contact__aside { display: grid; gap: var(--sp-3); }
.contact__intro { color: var(--fg-muted); margin-bottom: var(--sp-2); }
.contact__link {
  display: flex; align-items: center; gap: var(--sp-4);
  padding: var(--sp-4); background: var(--bg-elevated);
  border: 1px solid var(--border); border-radius: var(--radius);
  color: var(--fg-soft);
  transition: transform var(--t-fast) var(--ease-out), border-color var(--t-fast) var(--ease-out), color var(--t-fast) var(--ease-out);
}
.contact__link:hover { transform: translateY(-2px); border-color: var(--color-accent); color: var(--fg); }
.contact__link .icon { color: var(--color-accent); flex-shrink: 0; }
.contact__link span { display: flex; flex-direction: column; font-size: 0.95rem; word-break: break-word; }
.contact__link strong { font-weight: 600; color: var(--fg); font-size: 0.82rem; }

/* ---------- Footer ---------- */
.footer { border-top: 1px solid var(--border); padding-block: var(--sp-8); }
.footer__inner { display: flex; align-items: center; justify-content: space-between; gap: var(--sp-4); flex-wrap: wrap; }
.footer__brand { font-weight: 700; }
.footer__copy { color: var(--fg-muted); font-size: 0.9rem; }
.footer__top {
  display: inline-flex; align-items: center; gap: var(--sp-2);
  font-size: 0.9rem; font-weight: 500; color: var(--fg-soft);
  transition: color var(--t-fast) var(--ease-out);
}
.footer__top:hover { color: var(--color-accent); }

/* ---------- Scroll reveal ---------- */
.reveal { opacity: 0; transform: translateY(24px); transition: opacity 0.7s var(--ease-out), transform 0.7s var(--ease-out); }
.reveal.is-visible { opacity: 1; transform: none; }

/* ---------- Responsive ---------- */
@media (max-width: 900px) {
  .hero__inner { grid-template-columns: 1fr; gap: var(--sp-12); }
  .hero__visual { order: -1; }
  .hero__photo { width: min(320px, 70%); }
  .about { grid-template-columns: 1fr; gap: var(--sp-8); }
  .about__stats { grid-template-columns: repeat(3, 1fr); }
  .skills { grid-template-columns: 1fr; }
  .contact { grid-template-columns: 1fr; gap: var(--sp-8); }
}

@media (max-width: 720px) {
  .nav__links { display: none; }
  .nav__burger { display: inline-grid; }
  .section { padding-block: var(--sp-16); }
  .hero { padding-top: calc(var(--nav-h) + var(--sp-16)); }
  .about__stats { grid-template-columns: 1fr; }
  .stat { flex-direction: row; align-items: center; gap: var(--sp-3); }
  .stat__label { width: auto; margin-top: 0; }
}

@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  *, *::before, *::after {
    animation-duration: 0.01ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.01ms !important;
  }
  .reveal { opacity: 1; transform: none; }
}