:root {
  --paper: #fbfbf8;
  --white: #ffffff;
  --ink: #111314;
  --graphite: #2f3437;
  --muted: #687172;
  --line: #d9dedf;
  --wash: #f1f4f4;
  --blue-gray: #dfe9ec;
  --olive: #69765e;
  --olive-soft: #e8ede4;
  --signal: #d5433b;
  --signal-soft: #f7dedb;
  --focus: #1c62b9;
  --shadow: 0 18px 45px rgba(17, 19, 20, 0.08);
}

* {
  box-sizing: border-box;
  letter-spacing: 0;
}

html {
  scroll-behavior: smooth;
}

body {
  margin: 0;
  color: var(--ink);
  background: var(--paper);
  font-family: "Apple SD Gothic Neo", "Noto Sans KR", "Malgun Gothic", "Segoe UI", Arial, sans-serif;
  font-size: 16px;
  line-height: 1.65;
  text-align: left;
}

body.menu-open {
  overflow: hidden;
}

img {
  display: block;
  max-width: 100%;
  height: auto;
}

figure {
  margin: 0;
}

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

a:hover {
  color: var(--signal);
  text-decoration: none;
}

p {
  margin: 0 0 1rem;
}

h1,
h2,
h3,
h4,
h5,
h6 {
  margin: 0;
  color: var(--ink);
  font-weight: 700;
  line-height: 1.25;
}

ul,
ol {
  margin: 0;
  padding: 0;
}

button,
input,
select,
textarea {
  font: inherit;
}

button {
  cursor: pointer;
}

button:focus-visible,
a:focus-visible,
input:focus-visible,
select:focus-visible,
textarea:focus-visible {
  outline: 3px solid var(--focus);
  outline-offset: 3px;
}

.sr-only {
  position: absolute;
  width: 1px;
  height: 1px;
  padding: 0;
  overflow: hidden;
  clip: rect(0, 0, 0, 0);
  white-space: nowrap;
  border: 0;
}

.skip-link {
  position: fixed;
  z-index: 2000;
  top: 0.75rem;
  left: 0.75rem;
  padding: 0.75rem 1rem;
  background: var(--ink);
  color: var(--white);
  transform: translateY(-150%);
}

.skip-link:focus {
  transform: translateY(0);
}

.container {
  width: min(100% - 32px, 1180px);
  margin: 0 auto;
}

.container-narrow {
  width: min(100% - 32px, 880px);
  margin: 0 auto;
}

.site-body {
  padding-top: 76px;
}

.site-nav {
  position: fixed;
  z-index: 1200;
  top: 0;
  right: 0;
  left: 0;
  min-height: 76px;
  border-bottom: 1px solid var(--line);
  background: rgba(251, 251, 248, 0.96);
  backdrop-filter: blur(16px);
}

.site-nav .container {
  display: flex;
  align-items: center;
  min-height: 76px;
}

.navbar-brand {
  display: inline-flex;
  align-items: center;
  gap: 0.65rem;
  min-height: 44px;
  color: var(--ink);
  font-weight: 800;
}

.brand-mark {
  display: inline-grid;
  place-items: center;
  width: 34px;
  height: 34px;
  border: 1px solid var(--ink);
  background: var(--white);
}

.brand-mark::before,
.brand-mark::after {
  content: "";
  grid-area: 1 / 1;
  width: 18px;
  height: 1px;
  background: var(--signal);
}

.brand-mark::after {
  transform: rotate(90deg);
  background: var(--olive);
}

.navbar-toggler {
  display: none;
  width: 44px;
  height: 44px;
  margin-left: auto;
  border: 1px solid var(--ink);
  border-radius: 0;
  background: var(--white);
}

.navbar-toggler span {
  display: block;
  width: 20px;
  height: 2px;
  margin: 4px auto;
  background: var(--ink);
}

.navbar-collapse {
  display: flex;
  align-items: center;
  margin-left: auto;
}

.navbar-nav {
  display: flex;
  align-items: center;
  gap: 0.2rem;
  list-style: none;
}

.nav-link {
  display: inline-flex;
  align-items: center;
  min-height: 44px;
  padding: 0.45rem 0.75rem;
  color: var(--graphite);
  font-size: 0.95rem;
  font-weight: 700;
}

.nav-link.active {
  color: var(--signal);
}

.nav-cta {
  margin-left: 0.85rem;
}

.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-height: 44px;
  padding: 0.72rem 1rem;
  border: 1px solid var(--ink);
  border-radius: 6px;
  background: var(--white);
  color: var(--ink);
  font-weight: 800;
  line-height: 1.1;
  text-align: center;
  transition: background-color 0.2s ease, color 0.2s ease, border-color 0.2s ease;
}

.btn:hover {
  border-color: var(--signal);
  background: var(--signal);
  color: var(--white);
}

.btn-primary {
  border-color: var(--ink);
  background: var(--ink);
  color: var(--white);
}

.btn-secondary {
  border-color: var(--olive);
  background: var(--olive-soft);
}

.btn-ghost {
  background: transparent;
}

.section {
  padding: 5rem 0;
  border-top: 1px solid var(--line);
}

.section-tight {
  padding: 3.5rem 0;
}

.section-muted {
  background: var(--wash);
}

.section-blue {
  background: var(--blue-gray);
}

.eyebrow {
  display: inline-flex;
  align-items: center;
  gap: 0.45rem;
  margin-bottom: 1rem;
  color: var(--signal);
  font-size: 0.78rem;
  font-weight: 800;
}

.eyebrow::before {
  content: "";
  width: 28px;
  height: 1px;
  background: currentColor;
}

.lead {
  color: var(--graphite);
  font-size: 1.18rem;
}

.small-text {
  color: var(--muted);
  font-size: 0.92rem;
}

.hero {
  padding: 5.2rem 0 4rem;
  border-bottom: 1px solid var(--line);
}

.hero-grid {
  display: grid;
  grid-template-columns: minmax(0, 1.05fr) minmax(320px, 0.95fr);
  gap: 3rem;
  align-items: center;
}

.hero h1 {
  max-width: 760px;
  font-size: 3.35rem;
}

.hero-actions,
.inline-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 0.75rem;
  margin-top: 1.8rem;
}

.caption-row {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 0.75rem;
  margin-top: 2rem;
}

.caption-cell {
  min-height: 92px;
  padding: 0.9rem;
  border: 1px solid var(--line);
  background: var(--white);
}

.caption-cell strong {
  display: block;
  margin-bottom: 0.25rem;
}

.visual-frame {
  min-width: 0;
  overflow: hidden;
  border: 1px solid var(--ink);
  background: var(--white);
  box-shadow: var(--shadow);
}

.visual-frame img {
  width: 100%;
  aspect-ratio: 4 / 3;
  object-fit: cover;
}

.split-grid {
  display: grid;
  grid-template-columns: minmax(0, 0.86fr) minmax(0, 1.14fr);
  gap: 3rem;
  align-items: start;
}

.hero-grid > *,
.split-grid > * {
  min-width: 0;
}

.section-heading {
  margin-bottom: 2.4rem;
}

.section-heading h2 {
  max-width: 720px;
  font-size: 2.15rem;
}

.section-heading p {
  max-width: 720px;
  margin-top: 1rem;
  color: var(--muted);
}

.thesis-grid {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 1px;
  border: 1px solid var(--line);
  background: var(--line);
}

.thesis-item,
.system-item,
.note-card,
.study-card,
.faq-item,
.tech-note,
.discipline-card,
.sample-card,
.experiment-card {
  background: var(--white);
}

.thesis-item {
  min-height: 220px;
  padding: 1.25rem;
}

.thesis-item span,
.matrix-code,
.meta-label {
  display: block;
  color: var(--signal);
  font-size: 0.78rem;
  font-weight: 800;
}

.thesis-item h3 {
  margin: 0.65rem 0;
  font-size: 1.2rem;
}

.project-matrix {
  border-top: 2px solid var(--ink);
}

.matrix-head,
.project-row {
  display: grid;
  grid-template-columns: 0.65fr 1.05fr 1fr 0.9fr 1fr 1.8fr 1.1fr;
  gap: 1px;
  background: var(--line);
}

.matrix-head {
  color: var(--white);
  background: var(--ink);
}

.matrix-head span,
.project-row > div {
  min-width: 0;
  padding: 0.95rem;
}

.matrix-head span {
  color: var(--white);
  font-size: 0.82rem;
  font-weight: 800;
}

.project-row {
  border-bottom: 1px solid var(--line);
}

.project-row > div {
  background: var(--white);
}

.project-row h3 {
  font-size: 1.14rem;
}

.matrix-img {
  padding: 0 !important;
}

.matrix-img img {
  width: 100%;
  height: 100%;
  min-height: 138px;
  object-fit: cover;
}

.badge {
  display: inline-flex;
  align-items: center;
  min-height: 30px;
  padding: 0.3rem 0.55rem;
  border: 1px solid var(--line);
  background: var(--wash);
  color: var(--graphite);
  font-size: 0.82rem;
  font-weight: 800;
}

.badge-red {
  border-color: var(--signal);
  background: var(--signal-soft);
  color: var(--signal);
}

.system-grid,
.principle-grid,
.note-grid,
.collab-grid,
.study-grid,
.legend-grid,
.question-grid,
.tool-grid,
.sample-grid,
.discipline-grid,
.contact-grid {
  display: grid;
  gap: 1px;
  border: 1px solid var(--line);
  background: var(--line);
}

.system-grid {
  grid-template-columns: repeat(4, minmax(0, 1fr));
}

.principle-grid,
.note-grid,
.study-grid,
.legend-grid,
.question-grid,
.tool-grid,
.sample-grid,
.discipline-grid {
  grid-template-columns: repeat(3, minmax(0, 1fr));
}

.collab-grid {
  grid-template-columns: repeat(7, minmax(0, 1fr));
}

.contact-grid {
  grid-template-columns: minmax(0, 0.9fr) minmax(0, 1.1fr);
}

.system-item,
.principle-item,
.note-card,
.study-card,
.legend-item,
.question-card,
.tool-item,
.sample-card,
.discipline-card,
.contact-panel {
  min-height: 150px;
  padding: 1.15rem;
  background: var(--white);
}

.system-item strong,
.principle-item strong,
.tool-item strong {
  display: block;
  margin-bottom: 0.45rem;
}

.principle-item {
  border-left: 4px solid var(--olive);
}

.note-card,
.study-card,
.question-card,
.tech-note,
.discipline-card,
.sample-card,
.experiment-card,
.faq-item,
.contact-panel {
  border-radius: 0;
}

.note-card img,
.study-card img {
  width: 100%;
  aspect-ratio: 16 / 10;
  object-fit: cover;
  margin-bottom: 1rem;
  border: 1px solid var(--line);
}

.strip {
  display: grid;
  grid-template-columns: minmax(0, 1fr) auto;
  gap: 1.5rem;
  align-items: center;
  padding: 1.5rem;
  border: 1px solid var(--ink);
  background: var(--white);
}

.page-hero {
  padding: 4.6rem 0 3.2rem;
  border-bottom: 1px solid var(--line);
}

.page-hero h1 {
  max-width: 850px;
  font-size: 2.85rem;
}

.page-hero p {
  max-width: 740px;
  margin-top: 1rem;
}

.filter-bar,
.tab-buttons {
  display: flex;
  flex-wrap: wrap;
  gap: 0.5rem;
  margin-bottom: 1.5rem;
}

.filter-button,
.tab-button {
  min-height: 40px;
  padding: 0.55rem 0.8rem;
  border: 1px solid var(--line);
  border-radius: 6px;
  background: var(--white);
  color: var(--graphite);
  font-weight: 800;
}

.filter-button.active,
.tab-button.active {
  border-color: var(--ink);
  background: var(--ink);
  color: var(--white);
}

.is-hidden {
  display: none !important;
}

.systems-list {
  display: grid;
  gap: 1px;
  border: 1px solid var(--line);
  background: var(--line);
}

.system-panel {
  display: grid;
  grid-template-columns: 0.65fr 1fr;
  gap: 1px;
  background: var(--line);
}

.system-panel > div {
  padding: 1.3rem;
  background: var(--white);
}

.system-panel ul,
.plain-list {
  display: grid;
  gap: 0.55rem;
  list-style: none;
}

.system-panel li,
.plain-list li {
  position: relative;
  padding-left: 1.1rem;
}

.system-panel li::before,
.plain-list li::before {
  position: absolute;
  left: 0;
  color: var(--signal);
  content: "/";
}

.method-rail {
  display: grid;
  grid-template-columns: repeat(5, minmax(0, 1fr));
  gap: 1px;
  border: 1px solid var(--line);
  background: var(--line);
}

.method-step {
  min-height: 180px;
  padding: 1rem;
  background: var(--white);
}

.method-step span {
  display: inline-flex;
  margin-bottom: 0.85rem;
  color: var(--signal);
  font-weight: 900;
}

.tab-panel {
  padding: 1.4rem;
  border: 1px solid var(--line);
  background: var(--white);
}

.tab-panel[hidden],
.accordion-panel[hidden],
.cookie-banner[hidden] {
  display: none;
}

.experiment-grid {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 1px;
  border: 1px solid var(--line);
  background: var(--line);
}

.experiment-card {
  min-height: 260px;
  padding: 1.15rem;
}

.experiment-card dl {
  display: grid;
  gap: 0.65rem;
  margin: 1rem 0 0;
}

.experiment-card dt {
  color: var(--signal);
  font-weight: 800;
}

.experiment-card dd {
  margin: 0;
}

.accordion {
  display: grid;
  gap: 1px;
  border: 1px solid var(--line);
  background: var(--line);
}

.accordion-button {
  display: flex;
  justify-content: space-between;
  width: 100%;
  min-height: 58px;
  padding: 1rem;
  border: 0;
  background: var(--white);
  color: var(--ink);
  font-weight: 800;
  text-align: left;
}

.accordion-button::after {
  content: "+";
  margin-left: 1rem;
  color: var(--signal);
}

.accordion-button[aria-expanded="true"]::after {
  content: "-";
}

.accordion-panel {
  padding: 0 1rem 1rem;
  background: var(--white);
}

.form-grid {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 1rem;
}

.form-group {
  margin-bottom: 1rem;
}

.form-group.full {
  grid-column: 1 / -1;
}

.form-control {
  display: block;
  width: 100%;
  min-height: 48px;
  padding: 0.75rem 0.85rem;
  border: 1px solid var(--line);
  border-radius: 6px;
  background: var(--white);
  color: var(--ink);
}

textarea.form-control {
  min-height: 150px;
  resize: vertical;
}

.form-control[aria-invalid="true"] {
  border-color: var(--signal);
}

.field-error {
  min-height: 1.3rem;
  margin-top: 0.35rem;
  color: var(--signal);
  font-size: 0.88rem;
}

.form-check {
  display: flex;
  gap: 0.6rem;
  align-items: flex-start;
}

.form-check input {
  width: 20px;
  height: 20px;
  margin-top: 0.2rem;
}

.form-message {
  margin-top: 1rem;
  padding: 1rem;
  border: 1px solid var(--line);
  background: var(--wash);
}

.form-message.success {
  border-color: var(--olive);
  background: var(--olive-soft);
}

.privacy-block {
  display: grid;
  gap: 1px;
  border: 1px solid var(--line);
  background: var(--line);
}

.privacy-block article {
  padding: 1.1rem;
  background: var(--white);
}

.site-footer {
  padding: 3rem 0;
  border-top: 1px solid var(--ink);
  background: var(--ink);
  color: var(--white);
}

.site-footer a,
.site-footer h2,
.site-footer h3,
.site-footer p {
  color: var(--white);
}

.footer-grid {
  display: grid;
  grid-template-columns: 1.3fr 0.8fr 1fr;
  gap: 2rem;
}

.footer-links {
  display: grid;
  gap: 0.55rem;
  list-style: none;
}

.footer-note {
  margin-top: 2rem;
  color: #cbd2d5;
  font-size: 0.9rem;
}

.cookie-banner {
  position: fixed;
  z-index: 1300;
  right: 1rem;
  bottom: 1rem;
  display: grid;
  grid-template-columns: minmax(0, 1fr) auto;
  gap: 1rem;
  align-items: center;
  width: min(680px, calc(100% - 2rem));
  padding: 1rem;
  border: 1px solid var(--ink);
  background: var(--white);
  box-shadow: var(--shadow);
}

.cookie-banner p {
  margin: 0;
}

@media (max-width: 1040px) {
  .hero-grid,
  .split-grid,
  .contact-grid,
  .system-panel {
    grid-template-columns: 1fr;
  }

  .matrix-head {
    display: none;
  }

  .project-row {
    grid-template-columns: repeat(2, minmax(0, 1fr));
    margin-bottom: 1rem;
    border: 1px solid var(--line);
  }

  .matrix-img {
    grid-column: 1 / -1;
  }

  .collab-grid {
    grid-template-columns: repeat(3, minmax(0, 1fr));
  }

  .method-rail {
    grid-template-columns: repeat(3, minmax(0, 1fr));
  }
}

@media (max-width: 767px) {
  .site-body {
    padding-top: 68px;
  }

  .site-nav,
  .site-nav .container {
    min-height: 68px;
  }

  .navbar-toggler {
    display: inline-block;
  }

  .navbar-collapse {
    position: absolute;
    top: 68px;
    right: 0;
    left: 0;
    display: none;
    padding: 0.75rem 1rem 1rem;
    border-bottom: 1px solid var(--line);
    background: var(--paper);
  }

  .navbar-collapse.show {
    display: block;
  }

  .navbar-nav {
    display: grid;
    align-items: stretch;
    gap: 0;
  }

  .nav-link,
  .nav-cta {
    width: 100%;
    margin: 0;
  }

  .nav-link {
    border-bottom: 1px solid var(--line);
  }

  .hero,
  .page-hero {
    padding: 3.6rem 0 2.6rem;
  }

  .hero h1,
  .page-hero h1 {
    font-size: 2.1rem;
  }

  .caption-row,
  .thesis-grid,
  .system-grid,
  .principle-grid,
  .note-grid,
  .study-grid,
  .legend-grid,
  .question-grid,
  .tool-grid,
  .sample-grid,
  .discipline-grid,
  .experiment-grid,
  .footer-grid,
  .form-grid {
    grid-template-columns: 1fr;
  }

  .project-row {
    grid-template-columns: 1fr;
  }

  .collab-grid,
  .method-rail {
    grid-template-columns: 1fr;
  }

  .strip,
  .cookie-banner {
    grid-template-columns: 1fr;
  }

  .section {
    padding: 3.25rem 0;
  }
}

@media (prefers-reduced-motion: reduce) {
  *,
  *::before,
  *::after {
    scroll-behavior: auto !important;
    transition-duration: 0.01ms !important;
    animation-duration: 0.01ms !important;
    animation-iteration-count: 1 !important;
  }
}