:root {
  --font-color: #8b8b8b;
  --base-color: #fff;
  --accent-color: #ea4b4b;
  --primary-color: #000000;
  --blue-color: #3c8fe1;
  --green-color: #0c9395;
  --orange-color: #ff8c1b;
  --purple-color: #bd5494;
  --brown-color: #979755;
  --gray-color: #d9d9d9;
  --border: 0.8px solid #7b7b7b;
  --gray-font-color:#7b7b7b;
  --font-family-noto-sans: "Noto Sans JP", sans-serif;
  --font-family-noto-serif: "Noto Serif JP", sans-serif;
  --font-family-inter: "Inter", sans-serif;
  --base-font-size: 16;
  --rem-ratio: calc(1rem / var(--base-font-size));
}

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

body {
  color: var(--primary-color);
  font-weight: 350;
  font-family: var(--font-family-noto-sans);
  font-feature-settings: "palt";
}

@media (min-width: 640px) {
  body {
    background-image: url(../img/bg.png);
    background-repeat: repeat;
	background-attachment: fixed;
  }
}
@media (min-width: 640px) {
  .wrapper {
    height: 100svh;
    max-width: 450px;
    margin-inline: auto;
  }
}

@media (min-width: 640px) {
  main {
    box-shadow: 0 4px 64px rgba(25, 25, 25, 0.15);
  }
}

.header {
  position: sticky;
  top: 0;
  display: grid;
  place-items: center;
  color: var(--font-color);
  background-color: var(--base-color);
  padding-top: 30px;
  z-index: 99;
}

.top_header {
  width: 100%;
  position: sticky;
  top: 0;
  background-color: var(--base-color);
  box-shadow: 0 1px 4px rgb(0, 0, 0, 0.2);
  padding: 10px 46px;
  z-index: 99;
}

.back_link_container {
  position: sticky;
  top: 86px;
  width: 100%;
  display: grid;
  justify-content: flex-start;
}

.back_link {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 6px;
  font-size: calc(10 * var(--rem-ratio));
}

.back_link::before {
  width: 24px;
  height: 24px;
  content: "";
  display: block;
  background-image: url(../img/black-arrow.svg);
  background-repeat: no-repeat;
  background-position: center center;
}

.section {
  width: 100%;
}

.bg_blue {
  background-color: var(--blue-color);
}

.bg_green {
  background-color: var(--green-color);
}

.bg_orange {
  background-color: var(--orange-color);
}

.bg_purple {
  background-color: var(--purple-color);
}

.bg_brown {
  background-color: var(--brown-color);
}

.bg_red {
  background-color: var(--accent-color);
}

.btn_box {
  display: grid;
  place-items: center;
  gap: 40px;
  width: 100%;
}

.btn {
  width: 200px;
  display: grid;
  place-items: center;
  border-radius: 3px;
  color: var(--base-color);
  font-weight: 400;
  font-size: calc(14 * var(--rem-ratio));
  padding: 11px 0;
}

.btn_bk {
  width: 200px;
  display: grid;
  place-items: center;
  background-color: var(--primary-color);
  border-radius: 3px;
  color: var(--base-color);
  font-weight: 400;
  font-size: calc(14 * var(--rem-ratio));
  padding: 11px 0;
}

.btn_gray {
  width: 200px;
  display: grid;
  place-items: center;
  background-color: var(--font-color);
  border-radius: 3px;
  color: var(--base-color);
  font-weight: 400;
  font-size: calc(14 * var(--rem-ratio));
  padding: 11px 0;
}

.logo_container {
  width: 100%;
  position: fixed;
  left: 0;
  right: 0;
  bottom: 76px;
  display: grid;
  place-items: center;
  gap: 40px;
  background-color: var(--base-color);
  font-family: var(--font-family-inter);
  box-shadow: 0 -1px 4px rgb(0, 0, 0, 0.2);
  padding: 8px 0;
}

@media (min-width: 640px) {
  .logo_container {
    max-width: 450px;
    margin-inline: auto;
  }
}

.footer {
  width: 100%;
  display: grid;
  place-items: center;
  position: fixed;
  bottom: 0;
  background-color: var(--base-color);
  font-family: var(--font-family-inter);
  font-weight: 400;
  line-height: 1.2;
}

@media (min-width: 640px) {
  .footer {
    max-width: 450px;
    box-shadow: 0 4px 64px rgba(25, 25, 25, 0.15);
  }
}

.footer_logo_container {
  padding: 8px 0;
}

.logo_img {
  aspect-ratio: 143 / 20;
  object-fit: cover;
  width: fit-content;
}

.footer_nav {
  width: 100%;
}

.footer_nav__list {
  background-color: var(--primary-color);
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 15px 35px;
}

.footer_nav__item {
  font-size: calc(10 * var(--rem-ratio));
  color: var(--base-color);
}

.footer_nav__link {
  display: grid;
  place-items: center;
  padding: 11px 8px;
}