*,
*::before,
*::after {
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
  scroll-padding-top: 84px;
  scroll-snap-type: y proximity;
}

body,
h1,
h2,
h3,
p,
ul,
figure {
  margin: 0;

}

body {
  min-width: 320px;
  overflow-x: hidden;
  background: var(--color-bg);
  color: var(--color-text);
}

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

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

ul {
  list-style: none;
  padding: 0;
}

button,
a {
  -webkit-tap-highlight-color: transparent;
}

:root {
  --color-bg: #fafaf8;
  --color-text: #111111;
  --color-sub: #666666;
  --color-accent: #3d47b5;
  --color-line: #e8e8e3;
  --color-card: #ffffff;
  --color-soft: #f1f1ec;

  --font-en: "Inter", Arial, sans-serif;
  --font-kr: "Noto Sans KR", "Apple SD Gothic Neo", sans-serif;

  --header-height: 76px;
  --container: 1280px;
  --radius: 8px;
  --shadow: 0 18px 45px rgba(17, 17, 17, 0.08);
}

body {
  font-family: var(--font-kr);
  font-size: 16px;
  line-height: 1.7;
  letter-spacing: 0;
}

h1,
h2,
h3,
.nav-logo,
.nav-link,
.section-label,
.button,
.timeline-year,
.project-number {
  font-family: var(--font-en);
}

h1 {
  font-size: clamp(64px, 7vw, 132px);
  line-height: 0.95;
  font-weight: 800;
}

h1 span,
h1 strong {
  display: block;
}

h1 strong {
  margin-top: 22px;
  font-family: var(--font-kr);
  font-size: clamp(30px, 3.2vw, 54px);
  line-height: 1.2;
  font-weight: 700;
}

h2 {
  font-size: clamp(42px, 4.5vw, 72px);
  line-height: 1.05;
  font-weight: 800;
}

h3 {
  font-size: 22px;
  line-height: 1.35;
  font-weight: 700;
}

.lead-copy {
  margin-top: 34px;
  font-size: clamp(22px, 2vw, 34px);
  line-height: 1.45;
  font-weight: 700;
}

.sub-copy,
.section-heading p,
.contact-description {
  color: var(--color-sub);
  font-size: 18px;
}

.sub-copy {
  margin-top: 20px;
}

.section-label {
  color: var(--color-accent);
  font-size: 13px;
  font-weight: 700;
  letter-spacing: 0.12em;
  text-transform: uppercase;
}

/* 4. Layout */
.site-header {
  position: fixed;
  top: 0;
  left: 0;
  z-index: 100;
  width: 100%;
  height: var(--header-height);
  border-bottom: 1px solid rgba(232, 232, 227, 0.9);
  background: rgba(250, 250, 248, 0.88);
  backdrop-filter: blur(16px);
}

.nav {
  display: flex;
  align-items: center;
  justify-content: space-between;
  width: min(100% - 64px, var(--container));
  height: 100%;
  margin: 0 auto;
}

.nav-list {
  display: flex;
  align-items: center;
  gap: 8px;
}

.container {
  width: min(100% - 64px, var(--container));
  margin: 0 auto;
}

.section {
  min-height: 50vh;
  padding: 112px 0 76px;
  scroll-snap-align: start;
}

.intro-layout {
  display: grid;
  grid-template-columns: minmax(0, 1.08fr) minmax(360px, 0.72fr);
  gap: 72px;
  align-items: center;
}

.section-heading {
  display: grid;
  grid-template-columns: 0.9fr 1.1fr;
  gap: 42px;
  align-items: end;
  margin-bottom: 48px;
}

.section-heading .section-label {
  grid-column: 1 / -1;
}

.timeline {
  display: grid;
  gap: 0;
  border-top: 1px solid var(--color-line);
}

.timeline-item {
  display: grid;
  grid-template-columns: 260px 1fr;
  gap: 42px;
  padding: 30px 0;
  border-bottom: 1px solid var(--color-line);
}

.skills-grid {
  display: grid;
  grid-template-columns: repeat(4, minmax(0, 1fr));
  gap: 18px;
}

.project-grid {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 24px;
}

.site-footer {
  padding: 82px 0 32px;
  background: #efefea;
  color: var(--color-sub);
  text-align: center;
  scroll-margin-top: var(--header-height);
}

.footer-inner {
  display: grid;
  gap: 72px;
}

.nav-logo {
  font-size: 18px;
  font-weight: 800;
}

.nav-link {
  display: inline-flex;
  align-items: center;
  min-height: 42px;
  padding: 0 14px;
  border-radius: 999px;
  color: var(--color-sub);
  font-size: 14px;
  font-weight: 600;
  transition: color 180ms ease, background-color 180ms ease;
}

.nav-link:hover,
.nav-link:focus-visible,
.nav-link.is-active {
  background: rgba(61, 71, 181, 0.09);
  color: var(--color-accent);
  outline: none;
}

.profile-tags {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
  margin-top: 34px;
}

.profile-tags li {
  padding: 8px 14px;
  border: 1px solid var(--color-line);
  border-radius: 999px;
  background: rgba(255, 255, 255, 0.56);
  color: var(--color-sub);
  font-size: 14px;
}

.button-group {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
  margin-top: 38px;
}

.button {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-width: 148px;
  min-height: 50px;
  padding: 0 22px;
  border: 1px solid var(--color-accent);
  border-radius: var(--radius);
  font-size: 15px;
  font-weight: 700;
  transition: transform 180ms ease, background-color 180ms ease, color 180ms ease;
}

.button:hover,
.button:focus-visible {
  transform: translateY(-2px);
  outline: none;
}

.button-primary {
  background: var(--color-accent);
  color: #ffffff;
}

.button-secondary {
  background: transparent;
  color: var(--color-accent);
}

.button-secondary:hover,
.button-secondary:focus-visible {
  background: rgba(61, 71, 181, 0.08);
}

.image-frame {
  position: relative;
  overflow: hidden;
  border: 1px solid var(--color-line);
  border-radius: var(--radius);
  background:
    linear-gradient(135deg, rgba(61, 71, 181, 0.08), rgba(17, 17, 17, 0.02)),
    var(--color-soft);
}

.image-frame img {
  position: absolute;
  inset: 0;
  width: 100%;
  height: 100%;
  object-fit: cover;
}

.image-frame.is-missing img {
  display: none;
}

.image-placeholder {
  position: absolute;
  inset: 0;
  display: grid;
  place-items: center;
  opacity: 0;
  color: var(--color-sub);
  font-family: var(--font-en);
  font-size: 13px;
  font-weight: 700;
  letter-spacing: 0.12em;
  text-transform: uppercase;
}

.image-frame.is-missing .image-placeholder {
  opacity: 1;
}

.profile-figure {
  min-height: 580px;
}

.timeline-year {
  color: var(--color-accent);
  font-size: 15px;
  font-weight: 800;
}

.timeline-content ul {
  display: flex;
  flex-wrap: wrap;
  gap: 8px 10px;
  margin-top: 16px;
}

.timeline-content li {
  padding: 7px 12px;
  border-radius: 999px;
  background: var(--color-soft);
  color: var(--color-sub);
  font-size: 14px;
}

.skill-card,
.project-card {
  border: 1px solid var(--color-line);
  border-radius: var(--radius);
  background: rgba(255, 255, 255, 0.72);
}

.skill-card {
  min-height: 160px;
  padding: 26px;
}

.skill-card p {
  margin-top: 14px;
  color: var(--color-sub);
  font-size: 15px;
}

.project-card {
  overflow: hidden;
  transition: transform 220ms ease, box-shadow 220ms ease, border-color 220ms ease;
}

.project-card:hover,
.project-card:focus-within {
  transform: translateY(-8px) scale(1.01);
  border-color: rgba(61, 71, 181, 0.24);
  box-shadow: var(--shadow);
}

.project-image {
  aspect-ratio: 4 / 3;
  border-width: 0 0 1px;
  border-radius: 0;
}

.project-content {
  padding: 28px;
}

.project-number {
  margin-bottom: 10px;
  color: var(--color-accent);
  font-size: 12px;
  font-weight: 800;
  letter-spacing: 0.1em;
}

.project-content p:not(.project-number) {
  margin-top: 14px;
  color: var(--color-sub);
  font-size: 15px;
}

.text-link {
  display: inline-flex;
  margin-top: 24px;
  color: var(--color-accent);
  font-family: var(--font-en);
  font-size: 14px;
  font-weight: 800;
}

.text-link:hover,
.text-link:focus-visible,
.contact-info a:hover,
.contact-info a:focus-visible {
  text-decoration: underline;
  text-underline-offset: 4px;
  outline: none;
}

.footer-contact h2 {
  font-family: var(--font-kr);
  font-size: clamp(38px, 5vw, 72px);
  line-height: 1.1;
  font-weight: 700;
}

.footer-contact > p {
  margin-top: 18px;
  color: var(--color-sub);
  font-size: 18px;
}

.contact-info {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 20px;
  max-width: 760px;
  margin: 42px auto 0;
  font-style: normal;
}

.contact-info div {
  padding: 24px;
  border: 1px solid #deded6;
  border-radius: var(--radius);
  background: rgba(250, 250, 248, 0.68);
}

.contact-info span {
  display: block;
  margin-bottom: 8px;
  color: var(--color-sub);
  font-family: var(--font-en);
  font-size: 13px;
  font-weight: 700;
  letter-spacing: 0.1em;
  text-transform: uppercase;
}

.contact-info a {
  color: var(--color-text);
  font-size: clamp(18px, 2vw, 26px);
  font-weight: 700;
  overflow-wrap: anywhere;
}

.footer-bottom {
  display: flex;
  justify-content: center;
  gap: 18px;
  padding-top: 28px;
  border-top: 1px solid #deded6;
  font-size: 14px;
}

@media (prefers-reduced-motion: no-preference) {
  .section {
    animation: fadeUp 700ms ease both;
  }

  @keyframes fadeUp {
    from {
      opacity: 0;
      transform: translateY(14px);
    }

    to {
      opacity: 1;
      transform: translateY(0);
    }
  }
}

@media (prefers-reduced-motion: reduce) {
  html {
    scroll-behavior: auto;
  }

  *,
  *::before,
  *::after {
    transition-duration: 0.01ms !important;
    animation-duration: 0.01ms !important;
    animation-iteration-count: 1 !important;
  }
}

@media (max-width: 1180px) {
  .intro-layout,
  .section-heading {
    grid-template-columns: 1fr;
  }

  .intro-layout {
    gap: 46px;
  }

  .profile-figure {
    min-height: 460px;
  }

  .skills-grid {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }

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

@media (max-width: 768px) {
  :root {
    --header-height: 68px;
  }

  html {
    scroll-padding-top: 74px;
    scroll-snap-type: y proximity;
  }

  .nav,
  .container {
    width: min(100% - 32px, var(--container));
  }

  .nav {
    gap: 16px;
  }

  .nav-logo {
    flex: 0 0 auto;
    font-size: 15px;
  }

  .nav-list {
    overflow-x: auto;
    gap: 2px;
    padding-bottom: 4px;
  }

  .nav-link {
    min-height: 36px;
    padding: 0 10px;
    font-size: 13px;
    white-space: nowrap;
  }

  .section {
    min-height: auto;
    padding: 92px 0 58px;
  }

  .lead-copy br,
  .sub-copy br,
  .section-heading br {
    display: none;
  }

  .profile-figure {
    min-height: 360px;
  }

  .timeline-item {
    grid-template-columns: 1fr;
    gap: 14px;
    padding: 28px 0;
  }

  .skills-grid {
    grid-template-columns: 1fr;
  }

  .skill-card {
    min-height: 136px;
  }

  .project-content,
  .skill-card {
    padding: 22px;
  }

  .site-footer {
    padding: 66px 0 28px;
  }

  .contact-info,
  .footer-bottom {
    grid-template-columns: 1fr;
    flex-direction: column;
  }

  .footer-bottom {
    gap: 6px;
  }
}

@media (max-width: 480px) {
  body {
    font-size: 15px;
  }

  h1 {
    font-size: 54px;
  }

  h2 {
    font-size: 40px;
  }

  .button-group,
  .button {
    width: 100%;
  }

  .profile-tags li,
  .timeline-content li {
    font-size: 13px;
  }
}