@charset "UTF-8";

/* --- 1. 基本設定 (Design Concept) --- */
:root {
  --color-snow: #ffffff;
  --color-sky: #a0d2eb;
  /* 冬空の青 */
  --color-energy: #ff6700;
  /* 情熱のオレンジ */
  --color-text-main: #2c3e50;
  --color-text-light: #f0f8ff;
  --bg-dark: #1a1a1d;
  /* 科学的な深みのある黒 */

  --font-heading: "Roboto", "Helvetica Neue", Arial, sans-serif;
  --font-body: "Hiragino Kaku Gothic ProN", "Meiryo", sans-serif;
}

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

body {
  font-family: var(--font-body);
  color: var(--color-text-main);
  background: url(../img/main-visual.png) no-repeat center center fixed;
  background-size: cover;
  line-height: 1.8;
}

/* --- 2. 共通コンポーネント --- */
h1,
h2,
h3,
h4 {
  font-family: var(--font-heading);
  font-weight: 800;
  letter-spacing: 0.05em;
}

.container {
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 20px;
}

.section-title {
  font-size: 2.5rem;
  text-align: center;
  margin-bottom: 3rem;
  position: relative;
  color: var(--bg-dark);
}

.section-title::after {
  content: "";
  display: block;
  width: 390px;
  height: 4px;
  background: linear-gradient(90deg, var(--color-sky), var(--color-energy));
  margin: 10px auto 0;
}

.jp-sub-title {
  font-size: 0.7em;
  display: block;
  margin-top: 10px;
  color: #467993;
  text-shadow:
    0 0 5px var(--color-snow),
    0 0 3px var(--color-snow);
}

.jp-sub-title-blue {
  font-size: 0.5em;
  display: block;
  margin-top: 10px;
  color: #679cb6;
}

.jp-sub-title-cyan {
  font-size: 0.8em;
  display: block;
  margin-top: 10px;
  color: #679cb6;
  text-shadow:
    0 0 5px var(--color-snow),
    0 0 3px var(--color-snow);
}

.sp-br {
  display: none;
}

.btn {
  display: inline-block;
  padding: 12px 30px;
  background-color: var(--color-energy);
  color: white;
  text-decoration: none;
  font-weight: bold;
  transition: 0.3s;
  border-radius: 2px;
}

.btn:hover {
  opacity: 0.8;
  box-shadow: 0 0 15px rgba(255, 103, 0, 0.4);
}

/* --- 3. Header & Navigation --- */
.main-header {
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  /* スマホ(24px)からPC(40px)まで滑らかに可変し、ハンバーガーメニューの余白を確保 */
  padding: 15px clamp(24px, 2vw + 16.5px, 40px);
  display: flex;
  justify-content: space-between;
  align-items: center;
  z-index: 2000;
  transition: 0.3s;
}

.header-logo {
  display: block;
  line-height: 0;
  flex-shrink: 0;
  position: relative;
  z-index: 2002;
}

/* 背景を擬似要素に移動して、子要素(メニュー)のposition:fixedへの干渉を防ぐ */
.main-header::before {
  content: "";
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  background: rgba(15, 23, 42, 0.5);
  backdrop-filter: blur(10px);
  z-index: -1;
}

.header-logo img {
  height: 40px;
  width: auto;
  max-width: 50vw; /* ロゴが幅を取りすぎてハンバーガーメニューを押し出さないように制限 */
  object-fit: contain;
}

.nav-menu ul {
  display: flex;
  list-style: none;
  margin: 0;
  padding: 0;
}

.nav-menu li {
  margin-left: 30px;
}

.nav-menu a {
  color: var(--color-snow);
  text-decoration: none;
  font-weight: bold;
  font-size: 1rem;
  transition: 0.3s;
}

.nav-menu a:hover {
  color: var(--color-energy);
}

/* Hamburger Menu Icon */
/* --- 3. Header & Navigation 内の修正 --- */

.hamburger {
  display: none;
  cursor: pointer;
  width: 30px;
  height: 20px;
  position: relative;
  z-index: 2005; /* ロゴやナビより前面に */
  flex-shrink: 0;
  margin-left: auto; /* Flexbox内で右寄せを強制 */
}

/* メディアクエリ内（@media (max-width: 768px)）で display: block; になることを確認 */

.hamburger span {
  display: block;
  position: absolute;
  left: 0;
  width: 100%; /* 30pxいっぱいまで広げる */
  height: 2px; /* 線の太さ */
  background-color: var(--color-snow);
  border-radius: 2px;
  transition: all 0.3s ease; /* アニメーションを滑らかに */
}

/* 3本の線の位置を「上端・中央・下端」に固定 */
.hamburger span:nth-child(1) {
  top: 0;
}

.hamburger span:nth-child(2) {
  top: 9px;
}

.hamburger span:nth-child(3) {
  top: 18px;
}

/* --- アクティブ状態（クリック後）の形状 --- */
.hamburger.active span:nth-child(1) {
  top: 9px;
  transform: rotate(45deg);
}

.hamburger.active span:nth-child(2) {
  opacity: 0;
  left: -20px;
  /* 左に消えていくアニメーション */
}

.hamburger.active span:nth-child(3) {
  top: 9px;
  transform: rotate(-45deg);
}

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

.hamburger span:nth-child(2) {
  top: 9px;
}

.hamburger span:nth-child(3) {
  top: 18px;
}

/* Hamburger Active State */
.hamburger.active span:nth-child(1) {
  top: 9px;
  transform: rotate(45deg);
}

.hamburger.active span:nth-child(2) {
  opacity: 0;
}

.hamburger.active span:nth-child(3) {
  top: 9px;
  transform: rotate(-45deg);
}

/* --- 4. Hero Section --- */
.hero {
  position: relative;
  height: 100vh;
  display: flex;
  align-items: center;
  justify-content: center;
  text-align: center;
  color: var(--color-snow);
  overflow: hidden;
}

.hero-visual {
  display: none;
}

.overlay {
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  background: transparent;
}

.hero-content {
  position: relative;
  z-index: 1;
}

.hero-content h1 {
  /* スマホ(2.5rem)からPC(4rem)まで滑らかに可変 */
  font-size: clamp(2.5rem, 2.91vw + 1.82rem, 4rem);
  text-transform: uppercase;
  margin-bottom: 20px;
  text-shadow: 0 4px 10px rgba(0, 0, 0, 0.5);
}

.hero-content p {
  font-size: 1.2rem;
  margin-bottom: 30px;
}

/* --- 5. Intro & Biomechanics --- */
.intro {
  padding: 100px 0;
  text-align: center;
  background: rgba(236, 226, 211, 0.856);
}

.biomechanics-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
  gap: 20px;
  margin-top: 50px;
}

.bio-card {
  background: #fff;
  padding: 30px;
  border: 1px solid #eee;
  position: relative;
  overflow: hidden;
  transition: 0.3s;
}

.bio-card::before {
  content: "";
  position: absolute;
  top: 0;
  left: 0;
  width: 4px;
  height: 100%;
  background: var(--color-sky);
  transition: 0.3s;
}

.bio-card:hover {
  transform: translateY(-5px);
  box-shadow: 0 10px 30px rgba(160, 210, 235, 0.3);
}

.bio-card:hover::before {
  background: var(--color-energy);
}

.bio-step {
  font-size: 3rem;
  color: #eee;
  font-weight: 900;
  position: absolute;
  top: 10px;
  right: 20px;
  z-index: 0;
}

.bio-card h3,
.bio-card p {
  position: relative;
  z-index: 1;
}

/* --- 6. Video Section --- */
.video-section {
  background-color: rgba(26, 26, 29, 0.9);
  color: var(--color-snow);
  padding: 80px 0;
}

.video-section .section-title {
  color: var(--color-snow);
}

.section-lead {
  text-align: center;
  color: var(--color-snow);
  max-width: 800px;
  margin: 0 auto 50px;
}

.video-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(350px, 1fr));
  gap: 40px;
}

.video-card {
  background: rgba(255, 255, 255, 0.05);
  border: 1px solid rgba(160, 210, 235, 0.2);
}

.video-placeholder {
  width: 100%;
  aspect-ratio: 16/9;
  background: #000;
}

.video-placeholder iframe {
  width: 100%;
  height: 100%;
  display: block;
}

.video-text {
  padding: 25px;
}

/* Accordion */
.bio-details {
  margin-top: 15px;
  border-top: 1px solid rgba(160, 210, 235, 0.3);
}

.bio-summary {
  cursor: pointer;
  padding: 10px 0;
  color: var(--color-energy);
  font-weight: bold;
  font-size: 0.9rem;
  list-style: none;
  position: relative;
  padding-left: 20px;
  transition: 0.3s;
}

.bio-summary::before {
  content: "▶";
  position: absolute;
  left: 0;
  top: 50%;
  transform: translateY(-50%);
  font-size: 0.8em;
  transition: 0.3s;
}

.bio-details[open] .bio-summary::before {
  transform: translateY(-50%) rotate(90deg);
}

.bio-summary:hover {
  opacity: 0.8;
}

.point-box {
  margin-top: 10px;
  padding: 15px;
  background: rgba(160, 210, 235, 0.1);
  border-left: 3px solid var(--color-energy);
  animation: slideDown 0.3s ease-out;
}

.point-box h4 {
  color: var(--color-sky);
  margin-bottom: 5px;
  font-size: 0.9rem;
}

.point-box p {
  font-size: 0.9rem;
  margin-bottom: 15px;
}

.intro-text {
  font-size: 0.95rem;
  color: #ddd;
  margin-bottom: 10px;
}

/* --- 7. Glossary (Tricks) Section --- */
.glossary {
  padding: 80px 0;
  background: rgba(236, 226, 211, 0.856);
}

/* Formula Styles */
.formula-box {
  background: #1a1a1d;
  padding: 30px 20px;
  /* 適切な余白を設定 */
  border-radius: 8px;
  box-shadow: 0 5px 20px rgba(0, 0, 0, 0.05);
  text-align: center;
  margin-bottom: 30px;
  padding: 30px 0 20px;
}

.formula-box h2 {
  color: var(--color-snow);
}

.formula-box>p {
  color: var(--color-snow);
}

.formula-container {
  display: flex;
  flex-wrap: wrap;
  justify-content: center;
  gap: 10px;
  margin-bottom: 30px;
  font-family: var(--font-heading);
  font-size: 1.2em;
}

.formula-tag {
  background: #f0f0f0;
  padding: 8px 15px;
  border-radius: 4px;
  font-weight: bold;
}

.formula-tag.highlight {
  background: rgba(255, 103, 0, 0.1);
  color: var(--color-energy);
  border: 1px solid var(--color-energy);
}

.formula-operator {
  display: flex;
  align-items: center;
  color: #ccc;
  font-weight: bold;
}

.formula-example {
  background: #f8f9fa;
  padding: 20px;
  border-radius: 8px;
  border-left: 4px solid var(--color-sky);
  text-align: left;
  /* スマホ(100%)からPC(66.6%)まで滑らかに可変 (画面が狭くなると幅が広がる) */
  width: clamp(66.6%, 115.18% - 4.05vw, 100%);
  margin: 0 auto;
}

.example-label {
  font-size: 1rem;
  color: #888;
  text-transform: uppercase;
  margin-bottom: 10px;
  font-weight: bold;
}

.example-equation {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  align-items: center;
  font-family: "Courier New", monospace;
  font-size: 1.2rem;
  margin-bottom: 15px;
}

.example-part.highlight {
  color: var(--color-energy);
  font-weight: bold;
}

.example-operator {
  color: #ccc;
  font-size: 0.8em;
}

.result-arrow {
  color: var(--color-sky);
  font-size: 1.5rem;
  margin-bottom: 10px;
  margin-left: 70px;
}

.result-text {
  font-size: 1.6rem;
  font-weight: bold;
  color: var(--color-text-main);
  margin-bottom: 5px;
}

.result-note {
  font-size: 1rem;
  color: #888;
}

/* Quote Box */
.quote-box {
  background: var(--bg-dark);
  border: none;
  position: relative;
  padding-top: 10px;
}

.quote-box>p {
  color: var(--color-snow);
}

.quote-grab-icon {
  width: 50px;
  height: 50px;
  display: block;
  margin: 0 auto 20px;
}

.quote-title {
  font-size: 1.8rem;
  margin-bottom: 20px;
  color: var(--color-snow);
}

.quote-subtitle {
  display: block;
  font-size: 1rem;
  margin-top: 10px;
  font-weight: normal;
  color: var(--color-energy);
}

/* Grab Cards */
.grab-diagrams {
  display: grid;
  /* コンテンツ幅に合わせてカラム数を自動調整 (最小幅240px) */
  grid-template-columns: repeat(auto-fit, minmax(240px, 1fr));
  gap: 20px;
  margin-top: 40px;
}

.grab-card {
  background: var(--bg-dark);
  color: white;
  /* スマホ(20px)からPC(10px)まで滑らかに可変 (画面が狭くなると余白が増える) */
  padding: clamp(10px, 24.55px - 1.21vw, 20px);
  text-align: center;
  aspect-ratio: 1/1;
  display: flex;
  flex-direction: column;
  justify-content: center;
  align-items: center;
  border: 1px solid var(--color-sky);
  transition: 0.3s;
  cursor: pointer;
}

.grab-card:hover {
  box-shadow: 0 0 15px var(--color-sky);
  transform: scale(1.02);
}

.grab-visual {
  width: 80px;
  height: 80px;
  border: 2px solid var(--color-sky);
  border-radius: 50%;
  margin-bottom: 15px;
  position: relative;
}

.grab-visual::after {
  content: "";
  position: absolute;
  width: 10px;
  height: 10px;
  background: var(--color-energy);
  border-radius: 50%;
  top: 50%;
  left: 50%;
  transform: translate(-50%, -50%);
  box-shadow: 0 0 10px var(--color-energy);
}

/* --- 8. Footer --- */
footer {
  background: #111;
  color: #777;
  padding: 40px 0;
  text-align: center;
}

.social-links {
  display: flex;
  justify-content: center;
  gap: 25px;
  margin-bottom: 20px;
}

.social-icon {
  width: 24px;
  height: 24px;
  color: #777;
  transition: 0.3s;
}

.social-icon svg {
  fill: currentColor;
}

.social-icon:hover {
  color: var(--color-energy);
  transform: translateY(-3px);
}

/* --- 9. Modal Window --- */
.modal {
  display: none;
  position: fixed;
  z-index: 3000;
  left: 0;
  top: 0;
  width: 100%;
  height: 100%;
  overflow: auto;
  background-color: rgba(0, 0, 0, 0.85);
  animation: fadeIn 0.4s;
}

.modal-content {
  background-color: var(--bg-dark);
  color: var(--color-snow);
  margin: 8% auto;
  padding: 30px;
  border: 1px solid var(--color-sky);
  border-radius: 8px;
  width: 90%;
  max-width: 700px;
  position: relative;
  box-shadow: 0 0 30px rgba(160, 210, 235, 0.3);
  animation: slideDown 0.5s ease-out;
}

.modal-close {
  position: absolute;
  top: 10px;
  right: 20px;
  color: white;
  font-size: 30px;
  font-weight: bold;
  cursor: pointer;
  transition: 0.3s;
}

.modal-close:hover {
  color: var(--color-energy);
}

#modal-video-container {
  width: 100%;
  aspect-ratio: 16/9;
  background: #000;
  margin-bottom: 20px;
}

#modal-video-container img {
  width: 100%;
  height: 100%;
  object-fit: cover;
}

.modal-cta-btn {
  display: block;
  margin: 30px auto 0;
  border: none;
  cursor: pointer;
  font-size: 1rem;
  font-family: var(--font-body);
}

/* --- Animations --- */
.fade-in-up {
  opacity: 0;
  transform: translateY(30px);
  transition:
    opacity 0.8s ease-out,
    transform 0.8s ease-out;
}

.fade-in-up.visible {
  opacity: 1;
  transform: translateY(0);
}

.fade-in {
  animation: fadeIn 1.5s ease-out forwards;
}

@keyframes fadeIn {
  from {
    opacity: 0;
  }

  to {
    opacity: 1;
  }
}

@keyframes slideDown {
  from {
    opacity: 0;
    transform: translateY(-20px);
  }

  to {
    opacity: 1;
    transform: translateY(0);
  }
}

/* --- Responsive Media Queries --- */
@media (max-width: 768px) {
  .hamburger {
    display: block;
  }

  .nav-menu {
    position: fixed;
    z-index: 2001;
    top: 0;
    left: 0;
    width: 100%;
    background: rgba(15, 23, 42, 0.95);
    display: flex;
    flex-direction: column;
    height: 100vh;
    overflow-y: auto;
    padding: 80px 20px 20px;
    transition:
      opacity 0.3s,
      visibility 0.3s;
    text-align: center;
    opacity: 0;
    visibility: hidden;
  }

  .nav-menu.active {
    opacity: 1;
    visibility: visible;
  }

  .nav-menu ul {
    flex-direction: column;
  }

  .nav-menu li {
    margin: 20px 0;
  }

  .sp-br {
    display: inline;
  }
}