/* ============================================================
   base.css — 공용 디자인 시스템 (다크톤 / 멀티 액센트)
   인트로 페이지와 각 기능 페이지가 공유한다.
   ============================================================ */
:root{
  /* 배경 계층 */
  --bg-0:#05060a;      /* 최심부 */
  --bg-1:#0a0c14;
  --bg-2:#10131f;
  --bg-3:#171b2b;
  --line:rgba(255,255,255,.08);
  --line-2:rgba(255,255,255,.14);

  /* 텍스트 */
  --fg:#eef1f7;
  --fg-dim:#a6adc0;
  --fg-faint:#6b7288;

  /* 액센트 (다채로움) */
  --violet:#8b5cf6;
  --indigo:#6366f1;
  --cyan:#22d3ee;
  --teal:#2dd4bf;
  --magenta:#e879f9;
  --pink:#f472b6;
  --lime:#a3e635;
  --amber:#fbbf24;
  --red:#fb7185;

  --accent:var(--violet);

  /* 그라디언트 */
  --grad-aurora:linear-gradient(120deg,#8b5cf6 0%,#22d3ee 45%,#e879f9 100%);
  --grad-warm:linear-gradient(120deg,#fbbf24,#f472b6,#8b5cf6);
  --grad-cool:linear-gradient(120deg,#22d3ee,#6366f1,#8b5cf6);

  --radius:18px;
  --radius-sm:12px;
  --ease:cubic-bezier(.22,1,.36,1);
  --ease-out:cubic-bezier(.16,1,.3,1);

  --font-display:"Space Grotesk","Pretendard",system-ui,sans-serif;
  --font-ui:"Inter","Pretendard",system-ui,-apple-system,sans-serif;
  --font-mono:"JetBrains Mono",ui-monospace,"SFMono-Regular",monospace;
}

*{box-sizing:border-box;margin:0;padding:0}
html{scroll-behavior:smooth;-webkit-text-size-adjust:100%}
body{
  font-family:var(--font-ui);
  background:var(--bg-0);
  color:var(--fg);
  line-height:1.5;
  min-height:100vh;
  overflow-x:hidden;
  -webkit-font-smoothing:antialiased;
  text-rendering:optimizeLegibility;
}
a{color:inherit;text-decoration:none}
button{font-family:inherit;cursor:pointer;border:none;background:none;color:inherit}
::selection{background:var(--violet);color:#fff}

/* 스크롤바 */
::-webkit-scrollbar{width:10px;height:10px}
::-webkit-scrollbar-track{background:var(--bg-0)}
::-webkit-scrollbar-thumb{background:var(--bg-3);border-radius:10px;border:2px solid var(--bg-0)}
::-webkit-scrollbar-thumb:hover{background:#2a3050}

/* 필름 그레인 / 노이즈 오버레이 */
.grain{
  position:fixed;inset:0;z-index:9998;pointer-events:none;opacity:.045;mix-blend-mode:overlay;
  background-image:url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='120' height='120'%3E%3Cfilter id='n'%3E%3CfeTurbulence type='fractalNoise' baseFrequency='.85' numOctaves='2' stitchTiles='stitch'/%3E%3C/filter%3E%3Crect width='100%25' height='100%25' filter='url(%23n)'/%3E%3C/svg%3E");
}

/* 커스텀 커서 */
.cursor-dot,.cursor-ring{position:fixed;top:0;left:0;z-index:9999;pointer-events:none;border-radius:50%;
  transform:translate(-50%,-50%);will-change:transform}
.cursor-dot{width:6px;height:6px;background:#fff;mix-blend-mode:difference}
.cursor-ring{width:34px;height:34px;border:1px solid rgba(255,255,255,.5);
  transition:width .25s var(--ease),height .25s var(--ease),border-color .25s,background .25s}
.cursor-ring.hover{width:56px;height:56px;border-color:var(--cyan);background:rgba(34,211,238,.08)}
@media (hover:none),(pointer:coarse){.cursor-dot,.cursor-ring{display:none}}

/* ── 공용 상단 내비게이션 독 ── */
.deck{
  position:fixed;top:18px;left:50%;transform:translateX(-50%);z-index:200;
  display:flex;align-items:center;gap:6px;padding:8px;
  background:rgba(12,14,22,.6);backdrop-filter:blur(18px) saturate(150%);
  -webkit-backdrop-filter:blur(18px) saturate(150%);
  border:1px solid var(--line-2);border-radius:999px;
  box-shadow:0 12px 40px rgba(0,0,0,.5),inset 0 1px 0 rgba(255,255,255,.06);
  max-width:calc(100vw - 24px);
}
.deck-brand{display:flex;align-items:center;gap:9px;padding:8px 14px 8px 12px;font-weight:700;
  font-family:var(--font-display);letter-spacing:-.02em;white-space:nowrap}
.deck-logo{width:24px;height:24px;border-radius:8px;background:var(--grad-aurora);
  box-shadow:0 0 18px rgba(139,92,246,.6);flex:0 0 auto;
  animation:spin-slow 14s linear infinite}
@keyframes spin-slow{to{transform:rotate(360deg)}}
.deck-sep{width:1px;height:22px;background:var(--line-2);margin:0 2px}
.deck-links{display:flex;gap:4px;overflow-x:auto;scrollbar-width:none}
.deck-links::-webkit-scrollbar{display:none}
.deck-btn{position:relative;padding:9px 16px;border-radius:999px;font-size:14px;font-weight:600;
  color:var(--fg-dim);white-space:nowrap;transition:color .2s,background .2s;display:flex;align-items:center;gap:7px}
.deck-btn:hover{color:var(--fg);background:rgba(255,255,255,.06)}
.deck-btn.active{color:#fff;background:rgba(255,255,255,.1)}
.deck-btn .dot{width:6px;height:6px;border-radius:50%;background:var(--lime);box-shadow:0 0 8px var(--lime)}
.deck-add{width:38px;height:38px;border-radius:50%;color:var(--fg-faint);font-size:20px;
  display:grid;place-items:center;border:1px dashed var(--line-2);transition:.2s}
.deck-add:hover{color:var(--cyan);border-color:var(--cyan);transform:rotate(90deg)}

.btn{display:inline-flex;align-items:center;gap:8px;padding:12px 22px;border-radius:999px;
  font-weight:600;font-size:15px;transition:transform .2s var(--ease),box-shadow .2s,background .2s}
.btn-primary{background:var(--grad-cool);color:#fff;box-shadow:0 8px 30px rgba(99,102,241,.4)}
.btn-primary:hover{transform:translateY(-2px);box-shadow:0 12px 40px rgba(99,102,241,.6)}
.btn-ghost{border:1px solid var(--line-2);color:var(--fg);background:rgba(255,255,255,.03)}
.btn-ghost:hover{background:rgba(255,255,255,.08);transform:translateY(-2px)}

@media (prefers-reduced-motion:reduce){
  *{animation-duration:.001ms!important;animation-iteration-count:1!important;transition-duration:.001ms!important}
  html{scroll-behavior:auto}
}