@charset "utf-8";

/* =========
  Base
========= */
*,
*::before,
*::after {
  box-sizing: border-box;
}

html,
body {
  scroll-behavior: smooth;
  margin: 0;
  padding: 0;
}

body {
  font-family: "Noto Sans JP", "Hiragino Kaku Gothic ProN", "Meiryo", sans-serif;
  color: #222;
  line-height: 1.7;
}

img {
  height: auto;
  display: block;
}

section {
  scroll-margin-top: 100px; 
}


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

:root {
  --container: 1100px;
  --side: 40px;

  --header-h: 90px;

  --card-gap: 28px;
  --card-radius: 10px;
  --muted: #f2f2f2;
}

/* =========
  Header（固定）
========= */
header {
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  height: var(--header-h);
  background: #fff;
  border-bottom: 2px solid #0cbeff;
  z-index: 999;
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 0 var(--side);
}

.header_image img {
  width: 200px;
  height: auto;
}

header ul {
  list-style: none;     
  margin: 0;
  padding: 0;

  display: flex;         
  gap: 40px;            
  align-items: center;
}

.hamburger {
  display: none;
}

header ul li a{
  position: relative;
  color: #000000;
  text-decoration: none;
  padding-bottom: 6px;
}

header ul li a::after{
  content: "";
  position: absolute;
  left: 50%;
  bottom: 0;
  width: 0;
  height: 2px;
  transform: translateX(-50%);
  transition: width 0.3s ease;
}

header ul li a:hover::after{
  width: 100%;
}

header li.home a::after{
  background-color: #545454;
}

/* 海 */
header li.sea a::after{
  background-color: #00eeff;
}

/* 陸 */
header li.land a::after{
  background-color: #7cfc00;
}

/* 深海 */
header li.deepsea a::after{
  background-color: #4a00c0;
}

/* =========
  Video hero
========= */
main.video {
  width: 100%;
  height: 520px;
  position: relative;
  overflow: hidden;
  background: #ddd;
}

.video__background {
  position: absolute;
  inset: 0;
  width: 100%;
  height: 100%;
  object-fit: cover;
}

main.video p {
  font-size: 45px;
  color: #fff;
  margin: 0;
  position: absolute;
  left: 2%;
  bottom: 5%;
  border-radius: 20px;
  font-weight: 700;
}

/* =========
  Contents wrapper
========= */
article.contents {
  width: 100%;
  padding: 100px var(--side) 10px;
}

article.contents section {
  max-width: var(--container);
  margin: 0 auto 100px;
}

/* =========
  Section title
========= */
.sea_title,
.land_title,
.deepsea_title,
.aquarium_title {
  display: flex;
  justify-content: center;
  margin: 0 0 26px;
}

.sea_title h2 {
  margin: 0;
  padding: 0px 22px;
  border-bottom: #00eeff solid 4px;
  font-size: 25px;
}

.land_title h2 {
  margin: 0;
  padding: 0px 22px;
  border-bottom: #7cfc00 solid 4px;
  font-size: 25px;
}

.deepsea_title h2 {
  margin: 0;
  padding: 0px 22px;
  border-bottom: #4a00c0 solid 4px;
  font-size: 25px;
}
.aquarium_title h2 {
  margin: 0;
  font-size: 25px;
}

/* =========
  Grid（海/陸/深海：4列カード）
========= */
section.sea,
section.land,
section.deepsea {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: var(--card-gap);
  align-items: start;
}

section.sea .sea_title,
section.land .land_title,
section.deepsea .deepsea_title {
  grid-column: 1 / -1;
  margin-bottom: 8px;
}

.sea_contents{
  border: 3px solid #00eeff;
  border-radius: var(--card-radius);
  overflow: hidden;
  background: var(--muted);
  height: 480px;           
  display: flex;
  flex-direction: column;
}

.land_contents{
  border: 3px solid #7cfc00;
  border-radius: var(--card-radius);
  overflow: hidden;
  background: var(--muted);
  height: 500px;           
  display: flex;
  flex-direction: column;
}

.deepsea_contents{
  border: 3px solid #4a00c0;
  border-radius: var(--card-radius);
  overflow: hidden;
  background: var(--muted);
  height: 410px;           
  display: flex;
  flex-direction: column;
}

.sea_contents img,
.land_contents img,
.deepsea_contents img {
  width: 100%;
  object-fit: cover;
  border-bottom: 2px solid var(--border);
  background: #dcdcdc;
  height: 180px;
}

.sea_contents h2,
.land_contents h2,
.deepsea_contents h2 {
  font-size: 18px;
  line-height: 1.3;
  text-align: center;
}

.sea_contents p,
.land_contents p,
.deepsea_contents p {
  margin: 0 12px 14px;
  font-size: 13px;
  color: #333;
  flex-grow: 1;            
  overflow: hidden; 
}

/* =========
  Aquarium section
========= */
article.aquarium {
  padding: 10px var(--side) 100px;
}

article.aquarium > * {
  margin-left: auto;
  margin-right: auto;
}

article.aquarium > p {
  margin: 0 50px 14px;
}

article.aquarium hr {
  border: none;
  border-top: 2px solid #333;
  margin: 0 auto 24px;
  width: 100%;
}

.aquarium_contents {
  display: flex;
  justify-content: center;
  gap: 30px;
  align-items: flex-start;
  margin-bottom: 40px;
}

.aquarium_contents img {
  width: 500px;
}

.aquarium_contents p {
  width: 45%;
  margin: 60px 0 0;
  padding: 12px 14px;
}

/* =========
  Footer
========= */
footer {
  position: relative;
  height: 360px;
  background-image: url("../images/photo1.jpg");
  background-position: center;
  background-repeat: no-repeat;
  background-size: cover;
  
}

.footer_contents {
    margin: 0 auto;
    display: flex;
    justify-content: center;
    gap: 150px;
}

.footer_contents img {
    width: 200px;
    margin-top: 50px;
    background-color: rgba(255, 255, 255, 0.774);
}

.footer_contents ul {
  list-style: none;
  display: flex;   
  gap: 40px;   
}

.footer_contents ul li {
  color: #fff;
  font-size: 18px;
  margin-top: 120px;
}

.footer_contents ul li a {
  position: relative;
  color: #000000;
  background-color: rgba(255, 255, 255, 0.744);
  border-radius: 8px;
  text-decoration: none;
  padding: 20px;
  border: 3px solid transparent; 
  transition: color 0.3s ease;
}

/* Home */
footer li.home a {
  border-color: #545454;
  color: #000;
}

/* 海のいきもの */
footer li.sea a {
  border-color: #00eeff; 
  color: #000;
}

/* 陸のいきもの */
footer li.land a {
  border-color: #7cfc00; 
  color: #000;
}

/* 深海のいきもの */
footer li.deepsea a {
  border-color: #4a00c0; 
  color: #000;
}

/* Home */
footer li.home a:hover {
  color: #545454;
}

/* 海 */
footer li.sea a:hover {
  color: #00eeff;
}

/* 陸 */
footer li.land a:hover {
  color: #7cfc00;
}

/* 深海 */
footer li.deepsea a:hover {
  color: #4a00c0;
}

footer > p {
  position: absolute;
  bottom: 20px;            
  left: 50%;
  transform: translateX(-50%);
  margin: 0;
  font-size: 15px;
  text-align: center;
  color: #fff;
}


/* =========================
  Responsive CSS
========================= */

@media (max-width: 900px) {
  :root {
    --side: 4%;
    --container: 92%;
    --header-h: 76px;
  }

  /* ===== Header ===== */
  header {
    padding: 0 var(--side);
  }

  .header_image img {
    width: 60%;
    max-width: 260px;
  }

  .hamburger {
    display: block;
    width: 40px;
    height: 25px;
    position: relative;
    background: none;
    border: none;
    cursor: pointer;
  }

  .hamburger span {
    position: absolute;
    left: 0;
    width: 100%;
    height: 3px;
    background-color: #333;
    transition: 0.3s;
  }

  .hamburger span:nth-child(1) {
    top: 0;
  }

  .hamburger span:nth-child(2) {
    top: 50%;
    transform: translateY(-50%);
  }

  .hamburger span:nth-child(3) {
    bottom: 0;
  }

  /* nav をドロップダウン化 */
  .header_nav {
    position: absolute;
    left: 0;
    top: 100%;
    width: 100%;
    background: #fff;
    border-bottom: 2px solid #0cbeff;

    max-height: 0;
    overflow: hidden;
    transition: max-height 0.3s ease;
  }

  header.is-open .header_nav {
    max-height: 100vh;
  }

  .header_nav ul {
    list-style: none;
    margin: 0;
    padding: 3% 5% 5%;

    display: flex;
    flex-direction: column;
    gap: 0;
    align-items: stretch;
  }

  .header_nav li {
    width: 100%;
  }

  .header_nav li a {
    display: block;
    width: 100%;
    padding: 4% 3%;
    border-radius: 10px;
    background: rgba(240, 240, 240, 0.8);
    border: 2px solid transparent;
    margin: 2% 0;
  }

  .header_nav li.home a { border-color: #545454; color: #000; }
  .header_nav li.sea a { border-color: #00eeff; color: #000; }
  .header_nav li.land a { border-color: #7cfc00; color: #000; }
  .header_nav li.deepsea a { border-color: #4a00c0; color: #000; }

  .header_nav li.home a:hover { color: #545454; }
  .header_nav li.sea a:hover { color: #00eeff; }
  .header_nav li.land a:hover { color: #7cfc00; }
  .header_nav li.deepsea a:hover { color: #4a00c0; }

  .header_nav ul li a::after {
    display: none;
  }

  /* ===== Video ===== */
  main.video {
    height: 70vw;
    min-height: 280px;
    max-height: 520px;
  }

  main.video p {
    font-size: clamp(1.4rem, 4.2vw, 2.6rem);
    left: 4%;
    bottom: 6%;
  }

  /* ===== Contents wrapper ===== */
  section.sea,
  section.land,
  section.deepsea {
    grid-template-columns: repeat(2, 1fr);
    gap: var(--card-gap);
  }

  .sea_contents,
  .land_contents,
  .deepsea_contents {
    height: 300px;
    padding: 0 2px;
  }

  .sea_contents p,
  .land_contents p,
  .deepsea_contents p {
    overflow: auto;
  }

  /* ===== Aquarium ===== */
  article.aquarium {
    padding: 4% var(--side) 10%;
  }

  article.aquarium > p {
    width: 100%;
    margin: 0;
    padding: 4%;
    font-size: 13px;
    text-align: center;
  }

  .aquarium_contents {
    flex-direction: column;
    gap: 4%;
    align-items: center;
  }

  .aquarium_contents img {
    width: 100%;
    max-width: 100%;
  }

  .aquarium_contents p {
    width: 100%;
    margin: 0;
    padding: 4%;
    background: rgba(255, 255, 255, 0.72);
    border-radius: 10px;
  }

  /* ===== Footer ===== */
  footer {
    height: auto;
    min-height: 60vw;
    padding: 8% var(--side) 5%;
  }

  .footer_contents {
    gap: 6%;
  }

  .footer_contents img {
    width: 50%;
    margin-top: 0;
  }

  .footer_contents ul {
    flex-direction: column;
    gap: 4%;
    width: 100%;
    align-items: center;
    margin: 0;
    padding: 0;
    list-style: none;
  }

  .footer_contents ul li {
    margin-top: 0;
    width: 100%;
    display: flex;
    justify-content: center;
  }

  .footer_contents ul li a {
    width: 86%;
    text-align: center;
    padding: 4% 0;
    font-size: 1rem;
  }

  footer > p {
    position: static;
    transform: none;
    margin-top: 20%;
    font-size: 0.95rem;
    text-align: center;
  }
}