:root {
  --blue: #174bff;
  --yellow: #ffe04b;
  --ink: #161719;
  --paper: #fffdf6;
  --soft-blue: #eef4ff;
  --warm: #f7efe2;
  --muted: #6c6670;
}

* {
  box-sizing: border-box;
}

body {
  margin: 0;
  font-family: Pretendard, "Noto Sans KR", "Apple SD Gothic Neo", Arial, sans-serif;
  color: var(--ink);
  background:
    linear-gradient(90deg, rgba(23, 75, 255, 0.05) 1px, transparent 1px),
    linear-gradient(180deg, rgba(23, 75, 255, 0.05) 1px, transparent 1px),
    #fff;
  background-size: 44px 44px;
  word-break: keep-all;
  letter-spacing: 0;
}

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

.dong-page {
  min-height: 100vh;
  overflow: hidden;
}

.dong-nav {
  position: sticky;
  top: 0;
  z-index: 20;
  display: flex;
  justify-content: space-between;
  align-items: center;
  max-width: 1180px;
  margin: 0 auto;
  padding: 18px 22px;
  background: rgba(255, 255, 255, 0.9);
  border-bottom: 1px solid rgba(23, 75, 255, 0.14);
  backdrop-filter: blur(14px);
}

.dong-brand {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  font-weight: 950;
}

.dong-brand span {
  display: grid;
  place-items: center;
  width: 34px;
  height: 34px;
  border: 2px solid var(--ink);
  background: var(--yellow);
  color: var(--blue);
  box-shadow: 4px 4px 0 var(--blue);
}

.dong-nav-talk {
  padding: 11px 16px;
  border: 2px solid var(--ink);
  background: var(--yellow);
  font-weight: 950;
  box-shadow: 4px 4px 0 var(--blue);
}

.dong-hero {
  display: grid;
  grid-template-columns: minmax(0, 1.05fr) minmax(330px, 0.72fr);
  gap: 34px;
  align-items: center;
  max-width: 1180px;
  margin: 0 auto;
  padding: 76px 22px 70px;
}

.dong-eyebrow,
.dong-label {
  margin: 0 0 14px;
  color: var(--blue);
  font-size: 13px;
  font-weight: 950;
}

.dong-hero h1 {
  margin: 0;
  font-size: clamp(42px, 6vw, 76px);
  line-height: 1.05;
  font-weight: 950;
}

.dong-hero h1 span {
  background: linear-gradient(180deg, transparent 57%, var(--yellow) 57%);
}

.dong-hero p {
  max-width: 740px;
  margin: 24px 0 0;
  color: #44404a;
  font-size: 18px;
  line-height: 1.78;
}

.dong-hero-actions,
.dong-cta div {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
  margin-top: 30px;
}

.dong-hero-actions a,
.dong-cta a {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-height: 54px;
  padding: 0 22px;
  border: 2px solid var(--ink);
  background: var(--blue);
  color: #fff;
  font-weight: 950;
  box-shadow: 6px 6px 0 var(--yellow);
}

.dong-hero-actions a + a,
.dong-cta a + a {
  background: #fff;
  color: var(--ink);
  box-shadow: 6px 6px 0 rgba(23, 75, 255, 0.2);
}

.dong-visual {
  min-height: 460px;
  padding: 28px;
  border: 2px solid var(--ink);
  background:
    linear-gradient(140deg, rgba(255, 224, 75, 0.95), rgba(255, 255, 255, 0.96) 46%, rgba(23, 75, 255, 0.88));
  box-shadow: 14px 14px 0 var(--ink);
}

.dong-visual strong {
  display: block;
  font-size: clamp(42px, 5vw, 62px);
  line-height: 1;
}

.dong-visual span {
  display: block;
  margin-top: 10px;
  color: var(--blue);
  font-weight: 950;
}

.dong-visual p {
  margin: 70px 0 24px;
  font-size: 24px;
  line-height: 1.35;
  font-weight: 950;
}

.dong-visual ul {
  display: grid;
  gap: 12px;
  margin: 0;
  padding: 0;
  list-style: none;
}

.dong-visual li {
  display: flex;
  align-items: center;
  gap: 12px;
  padding: 14px;
  border: 2px solid var(--ink);
  background: rgba(255, 255, 255, 0.9);
  font-weight: 850;
}

.dong-visual b {
  color: var(--blue);
}

.dong-section,
.subject-list,
.keyword-links,
.review-section,
.dong-cta {
  max-width: 1180px;
  margin: 0 auto;
  padding: 72px 22px;
}

.dong-section h2,
.dong-band h2,
.keyword-links h2,
.review-head h2,
.dong-cta h2 {
  margin: 0;
  font-size: clamp(30px, 4.4vw, 52px);
  line-height: 1.16;
  font-weight: 950;
}

.dong-point-grid {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 16px;
  margin-top: 34px;
}

.dong-point-grid article {
  min-height: 210px;
  padding: 24px;
  border: 2px solid var(--ink);
  background: #fff;
  box-shadow: 8px 8px 0 rgba(23, 75, 255, 0.14);
}

.dong-point-grid span,
.subject-side span,
.review-grid span {
  display: inline-flex;
  width: max-content;
  padding: 8px 12px;
  background: var(--yellow);
  border: 2px solid var(--ink);
  font-size: 12px;
  font-weight: 950;
}

.dong-point-grid strong {
  display: block;
  margin-top: 18px;
  font-size: 23px;
}

.dong-point-grid p,
.subject-body p,
.review-grid p,
.dong-cta p,
.dong-band p {
  color: var(--muted);
  line-height: 1.72;
}

.dong-band {
  margin-top: 30px;
  padding: 70px 22px;
  background: var(--ink);
  color: #fff;
  border-top: 2px solid var(--ink);
  border-bottom: 2px solid var(--ink);
}

.dong-band > div {
  max-width: 1180px;
  margin: 0 auto;
}

.dong-band .dong-label {
  color: var(--yellow);
}

.dong-band p {
  max-width: 820px;
  color: rgba(255, 255, 255, 0.76);
  font-size: 18px;
}

.subject-list {
  display: grid;
  gap: 22px;
}

.subject-card {
  display: grid;
  grid-template-columns: 300px minmax(0, 1fr);
  gap: 20px;
  padding: 20px;
  border: 2px solid var(--ink);
  background: var(--paper);
  box-shadow: 10px 10px 0 rgba(23, 75, 255, 0.12);
}

.subject-side {
  min-height: 230px;
  padding: 22px;
  border: 2px solid var(--ink);
  background: var(--blue);
  color: #fff;
}

.subject-card.english .subject-side { background: #2c7a7b; }
.subject-card.korean .subject-side { background: #8a3ffc; }
.subject-card.science .subject-side { background: #0f766e; }
.subject-card.social .subject-side { background: #b45309; }
.subject-card.coding .subject-side { background: #111827; }

.subject-side h3 {
  margin: 26px 0 12px;
  font-size: 28px;
  line-height: 1.25;
}

.subject-side p {
  margin: 0;
  color: rgba(255, 255, 255, 0.82);
  line-height: 1.62;
}

.subject-body {
  display: flex;
  flex-direction: column;
  justify-content: center;
  gap: 18px;
}

.mini-grid {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 10px;
}

.mini-grid span {
  padding: 12px 14px;
  border: 1px solid #dce4f4;
  background: #fff;
  font-weight: 800;
}

.keyword-links {
  padding-top: 40px;
}

.keyword-button-grid {
  display: grid;
  grid-template-columns: repeat(4, minmax(0, 1fr));
  gap: 10px;
  margin-top: 28px;
}

.keyword-button-grid a {
  display: flex;
  align-items: center;
  justify-content: center;
  min-height: 48px;
  padding: 10px 12px;
  border: 2px solid var(--ink);
  background: #fff;
  text-align: center;
  font-size: 14px;
  font-weight: 900;
  box-shadow: 4px 4px 0 rgba(23, 75, 255, 0.14);
}

.review-section {
  max-width: none;
  background: var(--soft-blue);
  border-top: 2px solid var(--ink);
  border-bottom: 2px solid var(--ink);
}

.review-head,
.review-grid {
  max-width: 1180px;
  margin-left: auto;
  margin-right: auto;
}

.review-head {
  display: grid;
  grid-template-columns: minmax(0, 1fr) 220px;
  gap: 24px;
  align-items: end;
  margin-bottom: 26px;
}

.review-head img {
  width: 220px;
  aspect-ratio: 1;
  object-fit: cover;
  border: 2px solid var(--ink);
  box-shadow: 8px 8px 0 var(--yellow);
}

.review-grid {
  display: grid;
  grid-template-columns: repeat(4, minmax(0, 1fr));
  gap: 14px;
}

.review-grid article {
  min-height: 270px;
  display: flex;
  flex-direction: column;
  justify-content: space-between;
  padding: 22px;
  border: 2px solid var(--ink);
  background: #fff;
}

.review-grid article.featured {
  background: var(--ink);
  color: #fff;
}

.review-grid article.featured p {
  color: rgba(255, 255, 255, 0.78);
}

.review-grid strong {
  display: block;
  margin-top: 18px;
  color: var(--blue);
}

.review-grid article.featured strong {
  color: var(--yellow);
}

.dong-cta {
  text-align: center;
}

.dong-cta p {
  max-width: 760px;
  margin: 18px auto 0;
  font-size: 18px;
}

.dong-cta div {
  justify-content: center;
}

@media (max-width: 980px) {
  .dong-hero,
  .subject-card,
  .review-head {
    grid-template-columns: 1fr;
  }

  .dong-point-grid,
  .review-grid,
  .keyword-button-grid {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }
}

@media (max-width: 680px) {
  .dong-hero,
  .dong-section,
  .subject-list,
  .keyword-links,
  .review-section,
  .dong-cta {
    padding-left: 18px;
    padding-right: 18px;
  }

  .dong-hero h1 {
    font-size: 40px;
  }

  .dong-visual,
  .subject-card,
  .review-head img {
    box-shadow: 8px 8px 0 var(--ink);
  }

  .dong-point-grid,
  .review-grid,
  .keyword-button-grid,
  .mini-grid {
    grid-template-columns: 1fr;
  }
}

/* Shared long-form Study Studio detail image */
.detail-image-section {
  width: 100%;
  max-width: 1180px;
  margin: 0 auto;
  padding: 72px 20px;
  background: transparent;
  display: grid;
  place-items: center;
  box-sizing: border-box;
}

.detail-image-wrap {
  width: 100%;
  max-width: 852px;
  margin: 0 auto;
  overflow: hidden;
  background: transparent;
  border: 1px solid rgba(18, 48, 82, .14);
  box-shadow: 0 18px 44px rgba(18, 48, 82, .10);
}

.detail-image-wrap img {
  display: block;
  width: 100%;
  max-width: 852px;
  height: auto;
  margin: 0 auto;
}

@media (max-width: 680px) {
  .detail-image-section { padding: 38px 0; }
  .detail-image-wrap { border-left: 0; border-right: 0; box-shadow: none; }
}