/* ============================================================
   EtherXync — Design System (see DESIGN.md)
   Dark editorial × tech studio. One accent: Ether Mint.
   ============================================================ */

:root {
  /* Color */
  --bg: #0A0E14;
  --bg-elev: #10161F;
  --surface: #151D29;
  --line: rgba(148, 170, 197, 0.14);
  --line-strong: rgba(148, 170, 197, 0.28);
  --line-input: rgba(148, 170, 197, 0.55); /* 인터랙티브 요소 테두리 — 비텍스트 대비 3:1 확보 */
  --text: #E9EEF5;
  --text-2: #9AA7B8;
  --text-3: #6B7A8F;
  --accent: #63F2D2;
  --accent-ink: #06231C;   /* 민트 위에 올리는 텍스트 */
  --accent-bright: #8AF6DF; /* 민트 호버 톤 */
  --accent-dim: rgba(99, 242, 210, 0.12);
  --accent-glow: rgba(99, 242, 210, 0.07);
  --bg-veil: rgba(10, 14, 20, 0.82);        /* --bg의 반투명 파생 */
  --bg-veil-strong: rgba(10, 14, 20, 0.97);
  --success: #4ADE80;
  --error: #F87171;

  /* Type */
  --font-sans: "Pretendard Variable", Pretendard, -apple-system, BlinkMacSystemFont, "Segoe UI", "Malgun Gothic", sans-serif;
  --font-serif: "Instrument Serif", Georgia, serif;
  --font-mono: "JetBrains Mono", ui-monospace, SFMono-Regular, Consolas, monospace;

  /* Space (8px base) */
  --sp-sm: 0.5rem;
  --sp-md: 1rem;
  --sp-lg: 1.5rem;
  --sp-xl: 2rem;
  --sp-2xl: 3rem;
  --sp-3xl: 4rem;
  --sp-4xl: 6rem;
  --sp-section: 9rem;

  /* Radius */
  --r-sm: 6px;
  --r-md: 10px;
  --r-lg: 16px;

  /* Motion */
  --ease-enter: cubic-bezier(0.16, 1, 0.3, 1);
  --dur-short: 0.2s;
  --dur-med: 0.4s;
  --dur-long: 0.6s;

  --header-h: 4.5rem;
}

/* ---------- Reset ---------- */
*, *::before, *::after { box-sizing: border-box; }
* { margin: 0; }
html {
  scroll-behavior: smooth;
  -webkit-text-size-adjust: 100%;
}
body {
  background: var(--bg);
  color: var(--text);
  font-family: var(--font-sans);
  font-size: 1.0625rem;
  line-height: 1.7;
  -webkit-font-smoothing: antialiased;
  overflow-x: hidden;
  word-break: keep-all;      /* 한국어: 단어 중간 줄바꿈 방지 */
  overflow-wrap: break-word; /* 긴 URL·영문 토큰은 넘치지 않게 */
}
img, svg { display: block; max-width: 100%; }
a { color: inherit; text-decoration: none; }
button { font: inherit; color: inherit; background: none; border: none; cursor: pointer; }
ul, ol { padding: 0; list-style: none; }
h1, h2, h3 { line-height: 1.15; font-weight: 700; letter-spacing: -0.02em; }

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

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

/* ---------- Utilities ---------- */
.container {
  width: min(100% - 3rem, 1200px);
  margin-inline: auto;
}
.container-wide {
  width: min(100% - 3rem, 1320px);
  margin-inline: auto;
}
.mono-label {
  font-family: var(--font-mono);
  font-size: 0.8125rem;
  font-weight: 500;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--text-3);
}
.text-link {
  color: var(--text);
  border-bottom: 1px solid var(--line-strong);
  transition: border-color var(--dur-short), color var(--dur-short);
}
.text-link:hover { color: var(--accent); border-color: var(--accent); }

.skip-link {
  position: absolute;
  top: -100px;
  left: 1rem;
  z-index: 100;
  padding: 0.6rem 1rem;
  background: var(--accent);
  color: var(--bg);
  border-radius: var(--r-sm);
  font-weight: 600;
}
.skip-link:focus { top: 1rem; }

/* ---------- Buttons ---------- */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 0.5rem;
  padding: 0.875rem 1.75rem;
  border-radius: var(--r-sm);
  font-weight: 600;
  font-size: 1rem;
  line-height: 1.2;
  transition: background var(--dur-short), color var(--dur-short),
              border-color var(--dur-short), transform var(--dur-short);
}
.btn:active { transform: translateY(1px); }
.btn-primary {
  background: var(--accent);
  color: var(--accent-ink);
}
.btn-primary:hover { background: var(--accent-bright); }
.btn-ghost {
  border: 1px solid var(--line-input);
  color: var(--text);
}
.btn-ghost:hover { border-color: var(--accent); color: var(--accent); }
.btn-sm { padding: 0.55rem 1.15rem; font-size: 0.9375rem; }
.btn-block { width: 100%; }

/* ---------- Header ---------- */
.site-header {
  position: fixed;
  inset: 0 0 auto 0;
  z-index: 50;
  height: var(--header-h);
  transition: background var(--dur-med), border-color var(--dur-med);
  border-bottom: 1px solid transparent;
}
.site-header.is-scrolled {
  background: var(--bg-veil);
  backdrop-filter: blur(14px);
  -webkit-backdrop-filter: blur(14px);
  border-bottom-color: var(--line);
}
.header-inner {
  width: min(100% - 3rem, 1320px);
  margin-inline: auto;
  height: 100%;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: var(--sp-xl);
}
.wordmark {
  font-size: 1.25rem;
  font-weight: 700;
  letter-spacing: -0.02em;
}
.wordmark-x { color: var(--accent); }

.site-nav { display: flex; align-items: center; gap: var(--sp-xl); }
.site-nav ul { display: flex; gap: var(--sp-lg); }
.site-nav a:not(.btn) {
  font-size: 0.9375rem;
  font-weight: 500;
  color: var(--text-2);
  transition: color var(--dur-short);
}
.site-nav a:not(.btn):hover { color: var(--text); }

.nav-toggle {
  display: none;
  flex-direction: column;
  justify-content: center;
  gap: 6px;
  width: 44px;
  height: 44px;
  padding: 10px;
}
.nav-toggle span {
  display: block;
  height: 2px;
  width: 100%;
  background: var(--text);
  border-radius: 2px;
  transition: transform var(--dur-short), opacity var(--dur-short);
}
.nav-toggle[aria-expanded="true"] span:nth-child(1) { transform: translateY(4px) rotate(45deg); }
.nav-toggle[aria-expanded="true"] span:nth-child(2) { transform: translateY(-4px) rotate(-45deg); }

/* ---------- Hero ---------- */
.hero {
  position: relative;
  min-height: 100vh;  /* svh 미지원 브라우저 폴백 */
  min-height: 100svh;
  display: flex;
  flex-direction: column;
  justify-content: center;
  padding-top: var(--header-h);
  overflow: hidden;
}
.hero-glow {
  position: absolute;
  top: -20%;
  right: -10%;
  width: 60vw;
  height: 60vw;
  max-width: 900px;
  max-height: 900px;
  border-radius: 50%;
  background: radial-gradient(circle, var(--accent-glow) 0%, transparent 62%);
  pointer-events: none;
}
.hero-grid {
  position: absolute;
  inset: 0;
  background-image:
    linear-gradient(var(--line) 1px, transparent 1px),
    linear-gradient(90deg, var(--line) 1px, transparent 1px);
  background-size: 96px 96px;
  mask-image: radial-gradient(ellipse 80% 60% at 70% 30%, rgba(0,0,0,0.5), transparent 70%);
  -webkit-mask-image: radial-gradient(ellipse 80% 60% at 70% 30%, rgba(0,0,0,0.5), transparent 70%);
  pointer-events: none;
}
.hero-inner { position: relative; }
.hero-label { margin-bottom: var(--sp-lg); color: var(--accent); }
.hero-title {
  font-size: clamp(2.75rem, 7vw, 6rem);
  font-weight: 800;
  letter-spacing: -0.03em;
  line-height: 1.08;
}
.hero-accent { color: var(--accent); }
.hero-serif {
  font-family: var(--font-serif);
  font-style: italic;
  font-weight: 400;
  letter-spacing: 0;
  color: var(--text-2);
}
.hero-sub {
  margin-top: var(--sp-xl);
  max-width: 34em;
  font-size: clamp(1.0625rem, 1.5vw, 1.1875rem);
  color: var(--text-2);
}
.hero-actions {
  display: flex;
  flex-wrap: wrap;
  gap: var(--sp-md);
  margin-top: var(--sp-2xl);
}
.hero-bottom {
  position: relative;
  display: flex;
  align-items: center;
  gap: var(--sp-md);
  padding-bottom: var(--sp-xl);
  margin-top: auto;
}
.scroll-line {
  display: block;
  width: 72px;
  height: 1px;
  background: linear-gradient(90deg, var(--accent), transparent);
}

/* ---------- Ticker ---------- */
.ticker {
  border-block: 1px solid var(--line);
  overflow: hidden;
  padding: 1.1rem 0;
  background: var(--bg-elev);
}
.ticker-track {
  display: flex;
  width: max-content;
  animation: ticker 36s linear infinite;
  font-family: var(--font-mono);
  font-size: 0.875rem;
  letter-spacing: 0.12em;
  color: var(--text-3);
  white-space: nowrap;
}
/* 두 half가 (콘텐츠 + 뒤 여백)까지 완전히 동일해야
   translateX(-50%) 루프가 점프 없이 이어짐 */
.ticker-half {
  display: flex;
  align-items: center;
  gap: 2.5rem;
  padding-right: 2.5rem;
}
.ticker-track i { color: var(--accent); font-style: normal; }
.ticker:hover .ticker-track { animation-play-state: paused; }
@keyframes ticker {
  from { transform: translateX(0); }
  to   { transform: translateX(-50%); }
}

/* ---------- Sections ---------- */
.section { padding-block: var(--sp-section); }
.section-alt { background: var(--bg-elev); }
.section-head { margin-bottom: var(--sp-3xl); }
.section-index {
  display: inline-block;
  color: var(--accent);
  margin-bottom: var(--sp-lg);
}
.section-title {
  font-size: clamp(1.875rem, 3.5vw, 3rem);
  letter-spacing: -0.03em;
}
.section-desc {
  margin-top: var(--sp-md);
  color: var(--text-2);
  max-width: 38em;
}

/* ---------- About ---------- */
.about-grid {
  display: grid;
  grid-template-columns: 5fr 6fr;
  gap: var(--sp-3xl);
  align-items: start;
}
.about-grid .section-title { position: sticky; top: calc(var(--header-h) + 2rem); }
.about-body p + p { margin-top: var(--sp-lg); }
.about-body p { color: var(--text-2); font-size: 1.125rem; }
.about-keywords {
  display: flex;
  flex-wrap: wrap;
  gap: var(--sp-sm);
  margin-top: var(--sp-xl);
}
.about-keywords li {
  font-family: var(--font-mono);
  font-size: 0.8125rem;
  letter-spacing: 0.06em;
  padding: 0.45rem 0.9rem;
  border: 1px solid var(--line-strong);
  border-radius: 999px;
  color: var(--text-2);
}

/* ---------- Projects ---------- */
.projects-list { display: flex; flex-direction: column; gap: var(--sp-3xl); }

.project-card {
  display: grid;
  grid-template-columns: 6fr 5fr;
  gap: var(--sp-2xl);
  align-items: center;
  padding: var(--sp-xl);
  background: var(--surface);
  border: 1px solid var(--line);
  border-radius: var(--r-lg);
  transition: border-color var(--dur-med), transform var(--dur-med);
}
.project-card:hover { border-color: var(--line-strong); transform: translateY(-3px); }
.project-card:nth-child(even) .project-thumb { order: 2; }

.project-thumb {
  aspect-ratio: 16 / 10;
  border-radius: var(--r-md);
  border: 1px solid var(--line);
  position: relative;
  overflow: hidden;
  display: flex;
  align-items: center;
  justify-content: center;
}
.project-thumb .thumb-mark {
  font-family: var(--font-mono);
  font-size: clamp(2rem, 4vw, 3rem);
  font-weight: 500;
  color: var(--accent);
  opacity: 0.9;
  letter-spacing: -0.02em;
}
.project-thumb::after {
  content: "";
  position: absolute;
  inset: 0;
  background-image:
    linear-gradient(var(--line) 1px, transparent 1px),
    linear-gradient(90deg, var(--line) 1px, transparent 1px);
  background-size: 40px 40px;
  opacity: 0.6;
}
.project-thumb img { position: absolute; inset: 0; width: 100%; height: 100%; object-fit: cover; }

.project-body { min-width: 0; } /* 그리드 자식 넘침 방지 */

.project-meta {
  display: flex;
  align-items: center;
  flex-wrap: wrap;
  gap: var(--sp-sm);
  margin-bottom: var(--sp-md);
}
.tag {
  font-family: var(--font-mono);
  font-size: 0.75rem;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  padding: 0.3rem 0.7rem;
  border-radius: 999px;
  border: 1px solid var(--line-strong);
  color: var(--text-2);
}
.tag-accent { border-color: transparent; background: var(--accent-dim); color: var(--accent); }
.tag-sample { border-style: dashed; color: var(--text-3); }

.project-title { font-size: 1.5rem; margin-bottom: var(--sp-sm); }
.project-desc { color: var(--text-2); }
.project-links {
  display: flex;
  flex-wrap: wrap;
  gap: var(--sp-lg);
  margin-top: var(--sp-lg);
}
.project-links a {
  font-family: var(--font-mono);
  font-size: 0.8125rem;
  letter-spacing: 0.06em;
  color: var(--accent);
}
.project-links a:hover { text-decoration: underline; text-underline-offset: 4px; }

/* ---------- Services ---------- */
.service-rows { border-top: 1px solid var(--line); }
.service-row {
  position: relative;
  display: grid;
  grid-template-columns: 4rem 1fr auto;
  align-items: center;
  gap: var(--sp-xl);
  padding: var(--sp-xl) var(--sp-sm);
  border-bottom: 1px solid var(--line);
  transition: padding-left var(--dur-med) var(--ease-enter);
}
.service-row::after {
  content: "";
  position: absolute;
  left: 0;
  bottom: -1px;
  height: 1px;
  width: 0;
  background: var(--accent);
  transition: width var(--dur-long) var(--ease-enter);
}
.service-row:hover::after { width: 100%; }
.service-row:hover { padding-left: var(--sp-lg); }
.service-num { color: var(--accent); }
.service-text { min-width: 0; }
.service-text h3 { font-size: 1.375rem; margin-bottom: 0.35rem; }
.service-text p { color: var(--text-2); font-size: 1rem; }
.service-arrow {
  font-size: 1.375rem;
  color: var(--text-3);
  transition: color var(--dur-short), transform var(--dur-med) var(--ease-enter);
}
.service-row:hover .service-arrow {
  color: var(--accent);
  transform: translate(4px, -4px);
}

/* ---------- Process ---------- */
.process-steps {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: var(--sp-xl);
  counter-reset: step;
}
.process-step {
  padding: var(--sp-xl);
  background: var(--surface);
  border: 1px solid var(--line);
  border-radius: var(--r-md);
  position: relative;
}
.step-num { color: var(--accent); display: block; margin-bottom: var(--sp-md); }
.process-step h3 { font-size: 1.1875rem; margin-bottom: var(--sp-sm); }
.process-step p { color: var(--text-2); font-size: 0.9375rem; }

/* ---------- Collab ---------- */
.collab-box {
  position: relative;
  padding: clamp(2.5rem, 6vw, 5rem);
  border: 1px solid var(--line-strong);
  border-radius: var(--r-lg);
  background:
    radial-gradient(ellipse 70% 90% at 85% 10%, var(--accent-glow), transparent 60%),
    var(--bg-elev);
  overflow: hidden;
}
.collab-box p {
  margin-block: var(--sp-lg) var(--sp-xl);
  color: var(--text-2);
  max-width: 40em;
  font-size: 1.125rem;
}

/* ---------- Contact ---------- */
.contact-grid {
  display: grid;
  grid-template-columns: 5fr 6fr;
  gap: var(--sp-4xl);
  align-items: start;
}
.contact-info > p { color: var(--text-2); font-size: 1.125rem; }
.contact-meta {
  margin-top: var(--sp-2xl);
  display: flex;
  flex-direction: column;
  gap: var(--sp-lg);
}
.contact-meta dt { margin-bottom: 0.3rem; }
.contact-meta dd { margin: 0; font-size: 1.0625rem; }

.contact-form {
  display: flex;
  flex-direction: column;
  gap: var(--sp-lg);
  padding: var(--sp-xl);
  background: var(--surface);
  border: 1px solid var(--line);
  border-radius: var(--r-lg);
}
.field { display: flex; flex-direction: column; gap: 0.45rem; }
.field label {
  font-size: 0.9375rem;
  font-weight: 600;
}
.field label span { color: var(--accent); }
.field input,
.field select,
.field textarea {
  font: inherit;
  color: var(--text);
  background: var(--bg);
  border: 1px solid var(--line-input);
  border-radius: var(--r-sm);
  padding: 0.8rem 1rem;
  transition: border-color var(--dur-short);
  width: 100%;
}
.field textarea { resize: vertical; min-height: 8rem; }
.field input::placeholder,
.field textarea::placeholder { color: var(--text-3); }
.field input:focus,
.field select:focus,
.field textarea:focus {
  outline: none;
  border-color: var(--accent);
}
.field input[aria-invalid="true"],
.field textarea[aria-invalid="true"] {
  border-color: var(--error);
}
.field select {
  appearance: none;
  background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='12' height='8'%3E%3Cpath d='M1 1l5 5 5-5' stroke='%239AA7B8' stroke-width='1.5' fill='none' stroke-linecap='round'/%3E%3C/svg%3E");
  background-repeat: no-repeat;
  background-position: right 1rem center;
}
.form-note { font-size: 0.875rem; color: var(--text-3); }
.form-status { font-size: 0.9375rem; min-height: 1.5em; }
.form-status.is-error { color: var(--error); }
.form-status.is-success { color: var(--success); }

/* ---------- Footer ---------- */
.site-footer {
  border-top: 1px solid var(--line);
  padding-block: var(--sp-3xl);
}
.footer-inner {
  display: grid;
  grid-template-columns: 1fr auto auto;
  gap: var(--sp-3xl);
  align-items: start;
}
.footer-tag { margin-top: var(--sp-sm); color: var(--text-3); font-size: 0.9375rem; }
.footer-nav { display: flex; flex-direction: column; gap: 0.6rem; }
.footer-nav a {
  color: var(--text-2);
  font-size: 0.9375rem;
  transition: color var(--dur-short);
}
.footer-nav a:hover { color: var(--text); }
.footer-meta { text-align: right; display: flex; flex-direction: column; gap: var(--sp-md); align-items: flex-end; }

/* ---------- Reveal on scroll ---------- */
/* JS가 있을 때만 숨김 → JS 실패 시에도 콘텐츠는 항상 보임 */
html.js .reveal {
  opacity: 0;
  transform: translateY(24px);
  transition: opacity var(--dur-long) var(--ease-enter), transform var(--dur-long) var(--ease-enter);
}
html.js .reveal.is-visible { opacity: 1; transform: none; }

/* Anchor offset for fixed header */
section[id], [id="top"] { scroll-margin-top: var(--header-h); }

/* ---------- Responsive ---------- */
@media (max-width: 960px) {
  :root { --sp-section: 6.5rem; }

  .about-grid,
  .contact-grid { grid-template-columns: 1fr; gap: var(--sp-2xl); }
  .about-grid .section-title { position: static; }

  .process-steps { grid-template-columns: repeat(2, 1fr); }

  .project-card { grid-template-columns: 1fr; gap: var(--sp-lg); }
  .project-card:nth-child(even) .project-thumb { order: 0; }

  .footer-inner { grid-template-columns: 1fr; gap: var(--sp-xl); }
  .footer-meta { text-align: left; align-items: flex-start; }
}

@media (max-width: 720px) {
  :root { --sp-section: 5.5rem; }
  body { font-size: 1rem; }

  .br-desktop { display: none; }

  /* Mobile nav */
  .nav-toggle { display: flex; }
  .site-nav {
    position: fixed;
    inset: var(--header-h) 0 auto 0;
    flex-direction: column;
    align-items: stretch;
    gap: var(--sp-lg);
    padding: var(--sp-xl) var(--sp-lg) var(--sp-2xl);
    max-height: calc(100vh - var(--header-h));  /* svh 폴백 */
    max-height: calc(100svh - var(--header-h));
    overflow-y: auto; /* 가로 모드 등 낮은 화면에서 메뉴 넘침 방지 */
    background: var(--bg-veil-strong);
    backdrop-filter: blur(16px);
    -webkit-backdrop-filter: blur(16px);
    border-bottom: 1px solid var(--line);
    transform: translateY(-110%);
    transition: transform var(--dur-med) var(--ease-enter), visibility var(--dur-med);
    visibility: hidden;
  }
  .site-nav.is-open { transform: translateY(0); visibility: visible; }
  .site-nav ul { flex-direction: column; gap: var(--sp-md); }
  .site-nav a:not(.btn) { font-size: 1.125rem; }

  .process-steps { grid-template-columns: 1fr; }

  .service-row {
    grid-template-columns: 2.5rem 1fr;
    gap: var(--sp-md);
  }
  .service-arrow { display: none; }

  .hero-actions .btn { flex: 1 1 auto; }
  .contact-form { padding: var(--sp-lg); }
}

/* ---------- Reduced motion ---------- */
@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  .ticker-track { animation: none; }
  /* 숨김 규칙(html.js .reveal)과 명시도를 맞춰야 실제로 이김 */
  html.js .reveal {
    opacity: 1;
    transform: none;
    transition: none;
  }
  *, *::before, *::after {
    transition-duration: 0.01ms !important;
    animation-duration: 0.01ms !important;
  }
}