:root {
  --font-family-ja: "Noto Sans JP", sans-serif;
  --font-family-en: "Inter", sans-serif;
  --color-black: #3c4e59;
  --color-white: #fff;
  --color-gray: #dddddd;
  --color-lightGray: #eeeeee;
  --color-darkGray: #6c808c;
  --color-accent: #f79063;
}

* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}

html {
  font-size: calc(100vw / 160);
}

body {
  background-color: var(--color-gray);
  color: var(--color-black);
  font-family: var(--font-family-ja);
}

a {
  text-decoration: none;
  color: var(--color-black);
}

li {
  list-style: none;
}

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

h1,
h2,
h3,
h4,
p,
dt,
dd {
  font-weight: 400;
  letter-spacing: 0.04em;
}

h2 {
  font-size: 3rem;
  font-weight: 400;
}

p,
dt,
dd {
  font-size: 1.8rem;
  line-height: 200%;
}

.span-number {
  font-size: 1.6rem;
  font-weight: 400;
  font-family: var(--font-family-en);
}

/* //////////////// */
/* common */
/* //////////////// */

.frame {
  background: var(--color-white);
  margin: 3rem;
  border-radius: 12px;
  overflow: hidden;
}

.container {
  width: 100%;
  max-width: 140rem;
  margin: 0 auto;
  padding: 0 11rem;
}

.grid-2col {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
}

.grid-3col {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
}

.btn {
  display: inline-block;
  width: fit-content;
  box-shadow: 0 0 0 1px var(--color-black);
  padding: 1rem 2rem;
  border-radius: 50px;
  font-size: 1.8rem;
  font-weight: 400;
  align-self: end;
  transition: all 0.3s;
}

.btn:active,
.btn:hover {
  box-shadow: 0 0 0 1px var(--color-accent);
}

.heading-flex {
  display: flex;
  align-items: center;
  gap: 1rem;
}

.heading-en {
  font-size: 6.4rem;
  font-family: var(--font-family-en);
  letter-spacing: -0.04em;
}

.heading-accent {
  background-color: var(--color-accent);
  width: 1.5rem;
  height: 1.5rem;
  border-radius: 4px;
  margin-top: 4rem;
}

/* //////////////// */
/* header */
/* //////////////// */

.header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  height: 9.6rem;
  padding: 0 11rem;
}

.logo {
  width: 20rem;
}

.main-nav-ul {
  display: flex;
  gap: 5rem;
}

.main-nav-link {
  font-family: var(--font-family-en);
  font-size: 1.8rem;
  font-weight: 400;
  color: var(--color-black);
  letter-spacing: -0.04em;
  transition: all 0.3s;
}

.main-nav-link:active,
.main-nav-link:hover {
  color: var(--color-darkGray);
}

.contact-link {
  background-color: var(--color-black);
  color: var(--color-white);
  padding: 1rem 2rem;
  border-radius: 50px;
}

.contact-link:active,
.contact-link:hover {
  background-color: var(--color-white);
  color: var(--color-black);
  box-shadow: 0 0 0 1px var(--color-black);
}

.mobile-nav {
  display: none;
}

/* //////////////// */
/* contact */
/* //////////////// */

.contact-grid {
  height: 56rem;
  background: #f79063;
  background: linear-gradient(
    -112deg,
    rgba(247, 144, 99, 1) 0%,
    rgba(186, 11, 11, 1) 100%
  );
  border-radius: 10px;
  align-items: center;
  padding: 0 10rem;
  margin: 3rem 0;
  gap: 2rem;
  position: relative;
  transition: all 0.3s;
}

.contact-grid::after {
  content: "";
  position: absolute;
  inset: 0;
  background: rgba(0, 0, 0, 0.15);
  opacity: 0;
  transition: opacity 0.3s;
  pointer-events: none;
  z-index: 10;
}

.contact-grid:hover::after {
  opacity: 1;
}

.contact-link-overlay {
  position: absolute;
  inset: 0;
  z-index: 1;
}

.contact-text {
  color: var(--color-white);
  grid-column: 1 / 3;
}

.heading-contact {
  font-family: var(--font-family-en);
  letter-spacing: -0.04em;
  font-size: 9.6rem;
  margin-bottom: 2rem;
}

.contact-btn {
  align-self: center;
  justify-self: end;
  background-color: var(--color-white);
  box-shadow: none;
}

.btn-flex {
  display: flex;
  align-items: center;
  gap: 1rem;
}

/* //////////////// */
/* footer */
/* //////////////// */

.footer {
  padding: 7rem 0;
}

.footer-flex {
  height: 25rem;
  display: flex;
  flex-direction: column;
  justify-content: space-between;
}

.footer-top {
  display: flex;
  gap: 5rem;
  align-items: center;
}

.footer-nav-ul {
  display: flex;
  gap: 3rem;
  align-items: center;
}

.footer-nav-link {
  font-size: 1.6rem;
}

.footer-nav-link:active,
.footer-nav-link:hover {
  color: var(--color-darkGray);
}

.footer-bottom {
  display: flex;
  gap: 5rem;
  align-items: center;
}

.footer-copyright {
  font-family: var(--font-family-en);
}

.footer-privacy {
  font-size: 1.6rem;
  transition: all 0.3s;
}

.footer-privacy:active,
.footer-privacy:hover {
  color: var(--color-darkGray);
}

.footer-btn {
  background-color: var(--color-white);
  box-shadow: none;
  align-self: baseline;
  justify-self: end;
}

/* //////////////// */
/* queries*/
/* //////////////// */

@media screen and (max-width: 768px) {
  html {
    font-size: calc(100vw / 76.8);
  }

  .frame {
    margin: 1.5rem;
  }

  .container {
    padding: 0 6rem;
  }

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

  .grid-3col {
    grid-template-columns: repeat(1, 1fr);
  }

  /* //////////////// */
  /* header */
  /* //////////////// */

  .header {
    padding: 0 5rem;
  }

  .main-nav {
    position: fixed;
    height: 100vh;
    width: 100vw;
    top: 0;
    left: 0;
    background-color: var(--color-white);
    opacity: 0;
    visibility: hidden;
    pointer-events: none;
    transition: all 0.3s;
    z-index: 10;
    display: flex;
    align-items: end;
    padding: 4rem;
  }

  .main-nav-ul {
    display: flex;
    gap: 5rem;
    flex-direction: column;
    margin-bottom: 20rem;
  }

  .main-nav-link {
    font-size: 3.2rem;
  }

  .contact-link {
    padding: 2rem 4rem;
  }

  .mobile-nav {
    display: block;
    display: flex;
    flex-direction: column;
    gap: 1rem;
    cursor: pointer;
    z-index: 100;
  }

  .menu-bar {
    width: 5rem;
    height: 1px;
    background-color: var(--color-black);
    transition: all 0.3s;
  }

  .nav-open .main-nav {
    visibility: visible;
    opacity: 1;
    pointer-events: auto;
  }

  .nav-open .menu-bar-top {
    transform: rotate(13deg);
    transform-origin: top left;
  }

  .nav-open .menu-bar-bottom {
    transform: rotate(-13deg);
    transform-origin: bottom left;
  }

  /* //////////////// */
  /* contact */
  /* //////////////// */

  .contact-grid {
    padding: 0 5rem;
  }

  .contact-text {
    grid-column: 1 / 2;
  }

  /* //////////////// */
  /* footer */
  /* //////////////// */

  .footer-btn {
    display: none;
  }
}
