/* =========================================================
   Yunseob Song · QA 포트폴리오
   라이트/다크 모드 · 반응형 · 심플 & 트렌디
   ========================================================= */

:root {
  /* 라이트 모드 (기본) */
  --bg: #f6f7fb;
  --bg-elev: #ffffff;
  --bg-soft: #eef1f8;
  --text: #14161c;
  --text-soft: #5a6173;
  --border: #e4e7f0;
  --brand: #4f6ef7;
  --brand-2: #7b5cff;
  --brand-ink: #ffffff;
  --shadow: 0 10px 30px -12px rgba(28, 39, 84, 0.18);
  --shadow-sm: 0 4px 14px -8px rgba(28, 39, 84, 0.22);
  --radius: 16px;
  --radius-sm: 10px;
  --max: 1120px;
  --nav-h: 66px;
}

html[data-theme="dark"] {
  --bg: #0c0e14;
  --bg-elev: #14171f;
  --bg-soft: #1b1f2a;
  --text: #eef1f8;
  --text-soft: #9aa3b8;
  --border: #262b38;
  --brand: #6e8bff;
  --brand-2: #9b7bff;
  --brand-ink: #0c0e14;
  --shadow: 0 14px 40px -16px rgba(0, 0, 0, 0.6);
  --shadow-sm: 0 6px 18px -10px rgba(0, 0, 0, 0.6);
}

* { box-sizing: border-box; margin: 0; padding: 0; }

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

body {
  font-family: "Inter", "Noto Sans KR", system-ui, -apple-system, sans-serif;
  background: var(--bg);
  color: var(--text);
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
  transition: background .3s ease, color .3s ease;
}

a { color: inherit; text-decoration: none; }

.container { width: 100%; max-width: var(--max); margin: 0 auto; padding: 0 22px; }

/* ---------- 네비게이션 ---------- */
.nav {
  position: sticky; top: 0; z-index: 50;
  height: var(--nav-h);
  background: color-mix(in srgb, var(--bg-elev) 82%, transparent);
  backdrop-filter: saturate(160%) blur(12px);
  border-bottom: 1px solid var(--border);
  transition: background .3s ease, border-color .3s ease;
}
.nav__inner {
  height: 100%;
  max-width: var(--max); margin: 0 auto; padding: 0 22px;
  display: flex; align-items: center; justify-content: space-between; gap: 16px;
}

.brand { display: inline-flex; align-items: center; gap: 10px; font-weight: 800; letter-spacing: -.02em; }
.brand__mark {
  display: grid; place-items: center;
  width: 34px; height: 34px; border-radius: 9px;
  font-size: 13px; font-weight: 800; color: var(--brand-ink);
  background: linear-gradient(135deg, var(--brand), var(--brand-2));
  box-shadow: var(--shadow-sm);
}
.brand__text { font-size: 17px; }
.brand__dot { color: var(--brand); }
.brand--sm .brand__mark { width: 30px; height: 30px; font-size: 12px; }

.nav__menu { display: flex; align-items: center; gap: 6px; }
.nav__link {
  position: relative;
  padding: 8px 14px; border-radius: 999px;
  font-size: 14.5px; font-weight: 600; color: var(--text-soft);
  transition: color .2s ease, background .2s ease;
}
.nav__link:hover { color: var(--text); background: var(--bg-soft); }
.nav__link.is-active { color: var(--brand-ink); background: linear-gradient(135deg, var(--brand), var(--brand-2)); }

.nav__actions { display: flex; align-items: center; gap: 10px; }

.theme-toggle {
  position: relative; width: 44px; height: 30px;
  border: 1px solid var(--border); border-radius: 999px;
  background: var(--bg-soft); cursor: pointer; overflow: hidden;
  transition: background .2s ease, border-color .2s ease;
}
.theme-toggle__icon {
  position: absolute; top: 50%; transform: translateY(-50%);
  font-size: 14px; transition: opacity .25s ease, transform .25s ease;
}
.theme-toggle__icon--sun { left: 8px; opacity: 0; transform: translateY(-50%) scale(.6); }
.theme-toggle__icon--moon { right: 8px; opacity: 1; }
html[data-theme="dark"] .theme-toggle__icon--sun { opacity: 1; transform: translateY(-50%) scale(1); }
html[data-theme="dark"] .theme-toggle__icon--moon { opacity: 0; transform: translateY(-50%) scale(.6); }

.nav__burger { display: none; flex-direction: column; gap: 5px; width: 40px; height: 32px; padding: 7px 8px; border: 1px solid var(--border); border-radius: 9px; background: var(--bg-soft); cursor: pointer; }
.nav__burger span { display: block; height: 2px; border-radius: 2px; background: var(--text); transition: transform .25s ease, opacity .2s ease; }
.nav__burger[aria-expanded="true"] span:nth-child(1) { transform: translateY(7px) rotate(45deg); }
.nav__burger[aria-expanded="true"] span:nth-child(2) { opacity: 0; }
.nav__burger[aria-expanded="true"] span:nth-child(3) { transform: translateY(-7px) rotate(-45deg); }

/* ---------- 히어로 ---------- */
.hero { position: relative; overflow: hidden; padding: clamp(56px, 11vw, 120px) 0 clamp(48px, 8vw, 96px); }
.hero__bg {
  position: absolute; inset: -20% -10% auto -10%; height: 520px; z-index: 0;
  background:
    radial-gradient(40% 60% at 20% 20%, color-mix(in srgb, var(--brand) 28%, transparent), transparent 70%),
    radial-gradient(45% 55% at 85% 10%, color-mix(in srgb, var(--brand-2) 26%, transparent), transparent 70%);
  filter: blur(8px); pointer-events: none;
}
.hero__inner { position: relative; z-index: 1; max-width: 760px; }
.hero__eyebrow { font-size: 13px; font-weight: 700; letter-spacing: .12em; text-transform: uppercase; color: var(--brand); margin-bottom: 16px; }
.hero__title { font-size: clamp(30px, 6vw, 54px); line-height: 1.15; font-weight: 800; letter-spacing: -.03em; }
.grad { background: linear-gradient(120deg, var(--brand), var(--brand-2)); -webkit-background-clip: text; background-clip: text; color: transparent; }
.hero__desc { margin-top: 20px; font-size: clamp(15px, 2vw, 17px); color: var(--text-soft); max-width: 600px; }
.hero__cta { margin-top: 30px; display: flex; flex-wrap: wrap; gap: 12px; }
.hero__note { margin-top: 22px; font-size: 13px; color: var(--text-soft); }

/* ---------- 버튼 ---------- */
.btn { display: inline-flex; align-items: center; justify-content: center; gap: 8px; padding: 12px 20px; border-radius: 999px; font-size: 14.5px; font-weight: 700; border: 1px solid transparent; cursor: pointer; transition: transform .15s ease, box-shadow .2s ease, background .2s ease, border-color .2s ease; }
.btn:active { transform: translateY(1px); }
.btn--primary { color: var(--brand-ink); background: linear-gradient(135deg, var(--brand), var(--brand-2)); box-shadow: var(--shadow-sm); }
.btn--primary:hover { box-shadow: var(--shadow); transform: translateY(-2px); }
.btn--ghost { color: var(--text); background: var(--bg-elev); border-color: var(--border); }
.btn--ghost:hover { background: var(--bg-soft); transform: translateY(-2px); }
.btn--lg { padding: 14px 24px; font-size: 15.5px; }

/* ---------- 섹션 ---------- */
.section { padding: clamp(56px, 9vw, 96px) 0; }
.section--alt { background: var(--bg-soft); transition: background .3s ease; }
.section__head { text-align: center; max-width: 620px; margin: 0 auto clamp(34px, 5vw, 52px); }
.section__title { font-size: clamp(24px, 4vw, 34px); font-weight: 800; letter-spacing: -.02em; }
.section__sub { margin-top: 12px; color: var(--text-soft); font-size: 15.5px; }

/* ---------- 프로젝트 그리드 ---------- */
.grid { display: grid; grid-template-columns: repeat(2, 1fr); gap: 22px; }

.card {
  display: flex; flex-direction: column;
  background: var(--bg-elev); border: 1px solid var(--border);
  border-radius: var(--radius); padding: 26px;
  box-shadow: var(--shadow-sm);
  transition: transform .2s ease, box-shadow .25s ease, border-color .2s ease;
}
.card:hover { transform: translateY(-4px); box-shadow: var(--shadow); border-color: color-mix(in srgb, var(--brand) 40%, var(--border)); }

.card__top { display: flex; align-items: center; gap: 12px; margin-bottom: 14px; }
.card__badge {
  display: grid; place-items: center; flex-shrink: 0;
  width: 46px; height: 46px; border-radius: 12px;
  font-size: 13px; font-weight: 800; color: var(--brand-ink);
  background: linear-gradient(135deg, var(--brand), var(--brand-2));
}
.card__title { font-size: 18px; font-weight: 800; letter-spacing: -.01em; }
.card__url { font-size: 12.5px; color: var(--text-soft); word-break: break-all; }
.card__desc { color: var(--text-soft); font-size: 14.5px; margin-bottom: 18px; }

.specs { display: grid; gap: 10px; margin-bottom: 20px; }
.spec { display: grid; grid-template-columns: 86px 1fr; gap: 10px; align-items: start; font-size: 13.5px; }
.spec__key { font-weight: 700; color: var(--text); padding: 3px 0; }
.spec__val { color: var(--text-soft); }

.card__foot { margin-top: auto; display: flex; gap: 10px; flex-wrap: wrap; align-items: center; }
.tag { font-size: 11.5px; font-weight: 700; padding: 4px 10px; border-radius: 999px; background: var(--bg-soft); color: var(--text-soft); border: 1px solid var(--border); }
.tag--warn { color: #b26b00; border-color: color-mix(in srgb, #e0a106 40%, var(--border)); background: color-mix(in srgb, #f5c451 16%, transparent); }
html[data-theme="dark"] .tag--warn { color: #ffcf6b; }
.card__link { margin-left: auto; }

/* ---------- 깃허브 섹션 ---------- */
.github { display: flex; align-items: center; justify-content: space-between; gap: 24px; flex-wrap: wrap; }
.github__text { max-width: 560px; }

/* ---------- 푸터 ---------- */
.footer { border-top: 1px solid var(--border); padding: 28px 0; }
.footer__inner { display: flex; align-items: center; justify-content: space-between; gap: 16px; flex-wrap: wrap; }
.footer__copy { font-size: 13px; color: var(--text-soft); }

/* ---------- 반응형 ---------- */
@media (max-width: 860px) {
  .grid { grid-template-columns: 1fr; }
}

@media (max-width: 680px) {
  .nav__menu {
    position: fixed; top: var(--nav-h); left: 0; right: 0;
    flex-direction: column; align-items: stretch; gap: 4px;
    padding: 14px 18px 20px;
    background: var(--bg-elev); border-bottom: 1px solid var(--border);
    box-shadow: var(--shadow);
    transform: translateY(-12px); opacity: 0; pointer-events: none;
    transition: transform .22s ease, opacity .22s ease;
  }
  .nav__menu.is-open { transform: translateY(0); opacity: 1; pointer-events: auto; }
  .nav__link { padding: 12px 14px; border-radius: var(--radius-sm); font-size: 16px; }
  .nav__burger { display: flex; }
  .github { flex-direction: column; align-items: flex-start; }
}

@media (prefers-reduced-motion: reduce) {
  * { transition: none !important; scroll-behavior: auto !important; }
}