:root {
  --ink: #111827;
  --navy: #123e82;
  --blue: #2f7be6;
  --pale: #d6e4f8;
  --paper: #fbfcff;
}

* {
  box-sizing: border-box;
}

body {
  margin: 0;
  min-height: 100vh;
  background: #dfe7f1;
  color: var(--ink);
  font-family: "Yu Gothic", "YuGothic", "Hiragino Kaku Gothic ProN", "Meiryo", sans-serif;
}

.board {
  width: min(1500px, calc(100vw - 48px));
  margin: 0 auto;
  padding: 32px 0 48px;
}

.page-head {
  margin: 0 0 18px;
  display: flex;
  align-items: end;
  justify-content: space-between;
  gap: 24px;
  color: var(--navy);
}

.page-head p {
  margin: 0;
  font-family: Arial, sans-serif;
  font-size: 12px;
  font-weight: 800;
  letter-spacing: .16em;
}

.page-head h1 {
  margin: 0;
  font-size: 28px;
  font-weight: 900;
  letter-spacing: 0;
}

.spread-wrap {
  position: relative;
  overflow: hidden;
  border-radius: 14px;
  background: var(--paper);
  box-shadow:
    0 26px 70px rgba(18, 62, 130, .2),
    0 4px 16px rgba(17, 24, 39, .12);
}

.spread {
  display: block;
  width: 100%;
  height: auto;
}

.callout {
  position: absolute;
  width: 230px;
  padding: 14px 16px;
  border: 2px solid rgba(47, 123, 230, .55);
  border-radius: 12px;
  background: rgba(255, 255, 255, .94);
  box-shadow: 0 12px 26px rgba(18, 62, 130, .14);
  color: var(--ink);
}

.callout::after {
  content: "";
  position: absolute;
  width: 54px;
  height: 2px;
  background: var(--blue);
  transform-origin: left center;
}

.callout strong {
  display: block;
  margin-bottom: 6px;
  color: var(--navy);
  font-size: 15px;
  font-weight: 900;
}

.callout span {
  display: block;
  font-size: 12px;
  font-weight: 700;
  line-height: 1.55;
}

.callout-left-title {
  top: 7%;
  left: 3%;
}

.callout-left-title::after {
  right: -44px;
  top: 50%;
  transform: rotate(12deg);
}

.callout-flow {
  top: 34%;
  left: 3.5%;
}

.callout-flow::after {
  right: -50px;
  top: 50%;
  transform: rotate(-8deg);
}

.callout-book {
  bottom: 10%;
  left: 5%;
}

.callout-book::after {
  right: -45px;
  top: 32%;
  transform: rotate(-16deg);
}

.callout-right-title {
  top: 7%;
  right: 3%;
}

.callout-right-title::after {
  left: -54px;
  top: 50%;
  transform: rotate(172deg);
}

.callout-left-page {
  top: 38%;
  right: 28.5%;
}

.callout-left-page::after {
  right: -48px;
  top: 56%;
  transform: rotate(4deg);
}

.callout-right-page {
  top: 39%;
  right: 3.2%;
}

.callout-right-page::after {
  left: -54px;
  top: 50%;
  transform: rotate(180deg);
}

.callout-return {
  bottom: 8%;
  right: 20%;
}

.callout-return::after {
  left: -48px;
  top: 38%;
  transform: rotate(166deg);
}

@media (max-width: 1100px) {
  .board {
    width: calc(100vw - 24px);
    padding-top: 20px;
  }

  .page-head {
    align-items: flex-start;
    flex-direction: column;
    gap: 6px;
  }

  .callout {
    width: 190px;
    padding: 10px 12px;
  }

  .callout strong {
    font-size: 13px;
  }

  .callout span {
    font-size: 10px;
  }
}