:root {
  --bg: #ece2cf;
  --bg-ink: rgba(66, 53, 39, 0.1);
  --paper: #fffaf0;
  --paper-warm: #f8eddc;
  --ink: #241f19;
  --muted: #6c6258;
  --faint: rgba(36, 31, 25, 0.12);
  --school-green: #315d4f;
  --school-green-dark: #1f4037;
  --red-pencil: #b84d38;
  --red-soft: rgba(184, 77, 56, 0.13);
  --blue-pen: #446f95;
  --shadow: 0 22px 70px rgba(60, 48, 34, 0.16);
  --radius-xl: 34px;
  --radius-lg: 24px;
}

* {
  box-sizing: border-box;
}

html {
  min-height: 100%;
  scroll-behavior: smooth;
}

body {
  margin: 0;
  min-height: 100vh;
  color: var(--ink);
  background:
    radial-gradient(circle at 12% 8%, rgba(255, 255, 255, 0.72), transparent 26%),
    radial-gradient(circle at 88% 12%, rgba(184, 77, 56, 0.16), transparent 22%),
    linear-gradient(140deg, #f5ead9 0%, var(--bg) 52%, #d9e2d4 100%);
  font-family: "SUIT Variable", "Pretendard Variable", "Apple SD Gothic Neo",
    "Noto Sans KR", sans-serif;
}

body::before {
  content: "";
  position: fixed;
  inset: 0;
  z-index: -2;
  pointer-events: none;
  background-image:
    linear-gradient(var(--bg-ink) 1px, transparent 1px),
    linear-gradient(90deg, var(--bg-ink) 1px, transparent 1px);
  background-size: 42px 42px;
  -webkit-mask-image: linear-gradient(to bottom, rgba(0, 0, 0, 0.72), transparent 78%);
  mask-image: linear-gradient(to bottom, rgba(0, 0, 0, 0.72), transparent 78%);
}

body::after {
  content: "GMT";
  position: fixed;
  right: -0.12em;
  bottom: -0.23em;
  z-index: -1;
  color: rgba(49, 93, 79, 0.07);
  font-family: "Iowan Old Style", "AppleMyungjo", "Nanum Myeongjo", serif;
  font-size: min(38vw, 28rem);
  font-weight: 900;
  letter-spacing: -0.14em;
  pointer-events: none;
}

.page-shell {
  width: min(1120px, calc(100% - 36px));
  margin: 0 auto;
  padding: 42px 0 54px;
}

.hero {
  position: relative;
  display: grid;
  grid-template-columns: minmax(0, 1fr) 320px;
  gap: 28px;
  min-height: 560px;
  padding: clamp(26px, 4vw, 48px);
  overflow: hidden;
  border: 1px solid rgba(255, 255, 255, 0.58);
  border-radius: var(--radius-xl);
  background:
    linear-gradient(105deg, rgba(255, 250, 240, 0.96), rgba(255, 250, 240, 0.72)),
    repeating-linear-gradient(0deg, transparent 0 31px, rgba(68, 111, 149, 0.13) 32px);
  box-shadow: var(--shadow);
}

.hero::before {
  content: "1996-1998";
  position: absolute;
  top: 36px;
  right: clamp(24px, 4vw, 52px);
  color: rgba(184, 77, 56, 0.14);
  font-family: "Courier New", monospace;
  font-size: clamp(1.8rem, 5vw, 5.6rem);
  font-weight: 700;
  letter-spacing: -0.08em;
  transform: rotate(-4deg);
}

.hero-main,
.hero-note {
  position: relative;
  z-index: 1;
}

.hero-main {
  align-self: end;
  max-width: 780px;
}

.eyebrow,
.section-label,
.note-label {
  margin: 0 0 14px;
  color: var(--red-pencil);
  font-family: "Courier New", monospace;
  font-size: 0.78rem;
  font-weight: 700;
  letter-spacing: 0.16em;
  text-transform: uppercase;
}

.hero h1,
.panel h2,
.note-title {
  font-family: "Iowan Old Style", "AppleMyungjo", "Nanum Myeongjo", serif;
}

.hero h1 {
  max-width: 820px;
  margin: 0;
  font-size: clamp(2.75rem, 7vw, 6.5rem);
  line-height: 0.96;
  letter-spacing: -0.065em;
}

.hero-copy {
  max-width: 680px;
  margin: 28px 0 0;
  color: var(--muted);
  font-size: clamp(1.02rem, 1.4vw, 1.18rem);
  line-height: 1.85;
  word-break: keep-all;
}

.hero-copy strong {
  color: var(--ink);
  font-weight: 800;
}

.hero-links {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
  margin-top: 32px;
}

.hero-links a {
  display: inline-flex;
  align-items: center;
  min-height: 42px;
  padding: 0 17px;
  border: 1px solid rgba(49, 93, 79, 0.22);
  border-radius: 999px;
  color: var(--school-green-dark);
  background: rgba(255, 255, 255, 0.52);
  font-size: 0.95rem;
  font-weight: 800;
  text-decoration: none;
  transition: transform 180ms ease, background 180ms ease, color 180ms ease;
}

.hero-links a:first-child {
  color: #fffaf0;
  background: var(--school-green);
}

.hero-links a:hover {
  transform: translateY(-2px);
}

.hero-note {
  align-self: center;
  padding: 24px;
  border: 1px solid rgba(49, 93, 79, 0.18);
  border-radius: 28px;
  background:
    linear-gradient(150deg, rgba(49, 93, 79, 0.95), rgba(31, 64, 55, 0.96)),
    repeating-linear-gradient(0deg, transparent 0 27px, rgba(255, 255, 255, 0.08) 28px);
  color: #fff7e8;
  box-shadow: 0 22px 45px rgba(31, 64, 55, 0.23);
  transform: rotate(1.2deg);
}

.hero-note .note-label {
  color: #f1c7b6;
}

.note-title {
  margin: 0 0 20px;
  font-size: 2rem;
  line-height: 1.08;
  letter-spacing: -0.045em;
}

.hero-note ul {
  display: grid;
  gap: 10px;
  margin: 0;
  padding: 0;
  list-style: none;
}

.hero-note li {
  padding: 11px 12px;
  border: 1px solid rgba(255, 250, 240, 0.18);
  border-radius: 14px;
  background: rgba(255, 250, 240, 0.08);
  font-size: 0.96rem;
  font-weight: 700;
}

main {
  margin-top: 18px;
}

.panel {
  border: 1px solid rgba(255, 255, 255, 0.64);
  border-radius: var(--radius-lg);
  background:
    linear-gradient(145deg, rgba(255, 250, 240, 0.9), rgba(248, 237, 220, 0.76));
  box-shadow: var(--shadow);
  backdrop-filter: blur(10px);
}

.letter-panel {
  padding: clamp(26px, 5vw, 58px);
}

.panel h2 {
  max-width: 820px;
  margin: 0;
  font-size: clamp(2rem, 4.2vw, 4.15rem);
  line-height: 1.02;
  letter-spacing: -0.055em;
  word-break: keep-all;
}

.letter-body {
  display: grid;
  gap: 18px;
  max-width: 840px;
  margin-top: 34px;
  padding-left: clamp(16px, 3vw, 28px);
  border-left: 3px solid var(--red-soft);
}

.letter-body p,
.panel p,
.panel li,
.site-footer p {
  color: var(--muted);
  font-size: 1.02rem;
  line-height: 1.88;
  word-break: keep-all;
}

.letter-body p {
  margin: 0;
}

.content-grid {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  align-items: start;
  gap: 18px;
  margin-top: 18px;
}

.content-grid .panel,
.release-panel,
.update-panel {
  padding: 26px;
}

.content-grid .panel h2,
.release-panel h2,
.update-panel h2 {
  font-size: clamp(1.8rem, 3vw, 2.7rem);
}

.release-panel {
  margin-bottom: 18px;
}

.release-heading p {
  max-width: 850px;
  margin: 18px 0 0;
}

.download-grid {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 16px;
  margin-top: 24px;
}

.download-card {
  display: flex;
  flex-direction: column;
  justify-content: space-between;
  min-height: 280px;
  padding: 22px;
  border: 1px solid rgba(49, 93, 79, 0.2);
  border-radius: 20px;
  background:
    linear-gradient(145deg, rgba(255, 255, 255, 0.5), rgba(255, 250, 240, 0.32)),
    radial-gradient(circle at top right, rgba(49, 93, 79, 0.1), transparent 42%);
}

.platform-label {
  margin: 0 0 10px;
  color: var(--red-pencil);
  font-family: "Courier New", monospace;
  font-size: 0.8rem;
  font-weight: 900;
  letter-spacing: 0.14em;
  text-transform: uppercase;
}

.download-card h3 {
  margin: 0;
  color: var(--ink);
  font-family: "Iowan Old Style", "AppleMyungjo", "Nanum Myeongjo", serif;
  font-size: clamp(1.8rem, 3vw, 2.5rem);
  line-height: 1.05;
  letter-spacing: -0.045em;
}

.spec-list {
  display: grid;
  gap: 8px;
  margin: 20px 0 0;
  padding: 0;
  list-style: none;
}

.spec-list li {
  padding: 0;
  border: 0;
  background: transparent;
}

.download-button {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-height: 46px;
  margin-top: 24px;
  padding: 0 18px;
  border-radius: 999px;
  background: var(--school-green);
  color: #fffaf0;
  font-weight: 900;
  text-decoration: none;
}

.download-button.disabled {
  border: 1px dashed rgba(49, 93, 79, 0.4);
  background: rgba(49, 93, 79, 0.1);
  color: var(--school-green-dark);
}

.release-notice {
  margin-top: 18px;
  padding: 18px;
  border: 1px solid rgba(184, 77, 56, 0.18);
  border-radius: 18px;
  background: var(--red-soft);
}

.release-notice strong {
  display: block;
  color: var(--ink);
  font-weight: 900;
}

.release-notice p {
  max-width: 900px;
  margin: 8px 0 0;
}

.principles-panel,
.legacy-panel,
.thanks-panel {
  grid-column: 1 / -1;
}

.timeline-list,
.log-list,
.check-list,
.principle-list {
  margin: 24px 0 0;
  padding: 0;
  list-style: none;
}

.timeline-list,
.principle-list,
.check-list {
  display: grid;
  gap: 14px;
}

.principles-panel .principle-list {
  grid-template-columns: repeat(3, minmax(0, 1fr));
}

.legacy-panel p {
  max-width: 850px;
}

.legacy-ui-strip {
  display: flex;
  gap: 10px;
  align-items: end;
  margin-top: 24px;
  padding: 18px;
  overflow-x: auto;
  border: 1px solid var(--faint);
  border-radius: 18px;
  background:
    linear-gradient(90deg, rgba(255, 255, 255, 0.48), rgba(255, 255, 255, 0.2)),
    repeating-linear-gradient(90deg, transparent 0 23px, rgba(36, 31, 25, 0.06) 24px);
}

.legacy-ui-strip img {
  display: block;
  width: auto;
  max-height: 92px;
  flex: 0 0 auto;
  filter: sepia(0.12) saturate(0.95);
}

.legacy-metrics {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 12px;
  margin: 18px 0 0;
  padding: 0;
  list-style: none;
}

.legacy-metrics li {
  padding: 18px;
  border: 1px solid var(--faint);
  border-radius: 16px;
  background: rgba(255, 255, 255, 0.42);
}

.legacy-metrics strong,
.legacy-metrics span {
  display: block;
}

.legacy-metrics strong {
  color: var(--school-green-dark);
  font-family: "Courier New", monospace;
  font-size: clamp(1.55rem, 3vw, 2.5rem);
  line-height: 1;
}

.legacy-metrics span {
  margin-top: 8px;
  color: var(--muted);
  font-size: 0.95rem;
  font-weight: 700;
  line-height: 1.5;
}

.timeline-list li,
.principle-list li,
.check-list li,
.log-list li {
  position: relative;
  padding: 16px 16px 16px 18px;
  border: 1px solid var(--faint);
  border-radius: 16px;
  background: rgba(255, 255, 255, 0.42);
}

.timeline-list li::before,
.check-list li::before,
.principle-list li::before {
  content: "";
  position: absolute;
  top: 22px;
  left: -5px;
  width: 10px;
  height: 10px;
  border-radius: 50%;
  background: var(--red-pencil);
  box-shadow: 0 0 0 4px var(--red-soft);
}

.timeline-list span,
.principle-list strong,
.log-list time {
  display: block;
  color: var(--ink);
  font-weight: 900;
}

.timeline-list span,
.log-list time {
  font-family: "Courier New", monospace;
  font-size: 0.92rem;
}

.thanks-panel p,
.site-footer p {
  margin: 22px 0 0;
}

.thanks-panel p {
  max-width: 820px;
}

.update-panel {
  margin-top: 18px;
}

.log-list {
  display: grid;
  gap: 10px;
}

.site-footer {
  padding: 24px 6px 0;
}

.site-footer p {
  margin: 0;
  color: rgba(36, 31, 25, 0.58);
  font-size: 0.92rem;
  text-align: center;
}

@media (max-width: 860px) {
  .page-shell {
    width: min(100% - 22px, 1120px);
    padding: 22px 0 42px;
  }

  .hero {
    grid-template-columns: 1fr;
    min-height: auto;
  }

  .hero-main {
    align-self: start;
  }

  .hero-note {
    align-self: stretch;
    transform: none;
  }

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

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

  .principles-panel,
  .legacy-panel,
  .thanks-panel {
    grid-column: auto;
  }

  .principles-panel .principle-list {
    grid-template-columns: 1fr;
  }

  .legacy-metrics {
    grid-template-columns: 1fr;
  }
}

@media (max-width: 560px) {
  .hero,
  .letter-panel,
  .content-grid .panel,
  .release-panel,
  .update-panel {
    border-radius: 22px;
    padding: 22px;
  }

  .hero h1 {
    font-size: clamp(2.35rem, 15vw, 4rem);
  }

  .hero::before {
    top: 18px;
    right: 18px;
    font-size: 2.2rem;
  }

  .letter-body p,
  .panel p,
  .panel li {
    font-size: 0.98rem;
    line-height: 1.78;
  }

  .letter-body {
    padding-left: 16px;
  }
}