/* =====================
   カラーテーマ（ここだけ触れば全体変わる）
===================== */
:root {
  --bg-main: #0d0d0d;
  --bg-sub: #1a1a1a;
  --text-main: #ffffff;
  --text-sub: #aaaaaa;
  --border: #333333;
  --accent: #ffffff;
  --font-main: Arial, sans-serif;
  --header-height: 88px;
}

/* =====================
   全体
===================== */
* {
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
}

body {
  margin: 0;
  font-family: var(--font-main);
  background: var(--bg-main);
  color: var(--text-main);
}

body.menu-open {
  overflow: hidden;
}

a {
  color: inherit;
}

/* =====================
   ヘッダー
===================== */
header {
  position: sticky;
  top: 0;
  z-index: 1000;
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: 24px;
  padding: 20px 40px;
  border-bottom: 1px solid var(--border);
  width: 100%;
  min-height: var(--header-height);
  background: rgba(13, 13, 13, 0.96);
  backdrop-filter: blur(10px);
}

.logo {
  flex-shrink: 0;
}

.logo img {
  width: 300px;
  height: auto;
  display: block;
}

.nav-toggle {
  display: none;
  align-items: center;
  justify-content: center;
  width: 48px;
  height: 48px;
  padding: 0;
  border: 1px solid var(--border);
  background: transparent;
  color: var(--text-main);
  cursor: pointer;
  border-radius: 999px;
}

.nav-toggle-bar,
.nav-toggle-bar::before,
.nav-toggle-bar::after {
  display: block;
  position: relative;
  width: 20px;
  height: 2px;
  background: var(--text-main);
  transition: transform 0.3s ease, opacity 0.3s ease;
  content: "";
}

.nav-toggle-bar::before {
  position: absolute;
  top: -6px;
  left: 0;
}

.nav-toggle-bar::after {
  position: absolute;
  top: 6px;
  left: 0;
}

nav {
  display: flex;
  align-items: center;
  gap: 4px;
}

nav a {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-height: 40px;
  padding: 8px 12px;
  text-decoration: none;
  color: var(--text-main);
  font-size: 14px;
  letter-spacing: 0.04em;
  transition: opacity 0.3s, background-color 0.3s;
  border-radius: 999px;
}

nav a:hover {
  opacity: 1;
  background: var(--bg-sub);
}

/* =====================
   ヒーロー
===================== */
.hero {
  min-height: calc(100vh - var(--header-height));
  display: flex;
  align-items: center;
  justify-content: center;
  padding: 48px 24px;
}

.hero img {
  width: min(90%, 820px);
  height: auto;
  display: block;
}

/* =====================
   セクション
===================== */
.section {
  padding: 60px 40px;
}

.section h2 {
  margin-bottom: 20px;
  font-size: 22px;
  border-bottom: 1px solid var(--border);
  padding-bottom: 10px;
}

/* =====================
   グリッド
===================== */
.grid {
  display: flex;
  gap: 20px;
  flex-wrap: wrap;
}

.card {
  flex: 1 1 200px;
  background: var(--bg-sub);
  padding: 20px;
  border-radius: 8px;
}

/* =====================
   コンテナ
===================== */
.container {
  max-width: 600px;
  margin: 40px auto;
  padding: 0 20px;
}

.center {
  text-align: center;
}

/* =====================
   フォーム
===================== */
.container h1 {
  text-align: center;
  margin-bottom: 40px;
}

.container form {
  display: flex;
  flex-direction: column;
  gap: 15px;
}

.container input,
.container textarea,
.container select {
  width: 100%;
  padding: 12px;
  border: 1px solid var(--border);
  border-radius: 4px;
  background: var(--bg-sub);
  color: var(--text-main);
  font-family: var(--font-main);
  font-size: 14px;
}

.container button,
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 100%;
  padding: 12px;
  border: none;
  border-radius: 4px;
  background: var(--accent);
  color: var(--bg-main);
  font-weight: bold;
  font-size: 14px;
  cursor: pointer;
  transition: opacity 0.3s;
  text-decoration: none;
}

.container button:hover,
.btn:hover {
  opacity: 0.8;
}

/* =====================
   フッター
===================== */
footer {
  padding: 40px;
  text-align: center;
  border-top: 1px solid var(--border);
  font-size: 12px;
}

/* =====================
   モバイル
===================== */
@media (max-width: 768px) {
  :root {
    --header-height: 76px;
  }

  header {
    flex-direction: row;
    align-items: center;
    padding: 14px 16px;
    gap: 12px;
  }

  .logo img {
    width: 170px;
  }

  .nav-toggle {
    display: inline-flex;
    margin-left: auto;
  }

  .nav-toggle[aria-expanded="true"] .nav-toggle-bar {
    background: transparent;
  }

  .nav-toggle[aria-expanded="true"] .nav-toggle-bar::before {
    top: 0;
    transform: rotate(45deg);
  }

  .nav-toggle[aria-expanded="true"] .nav-toggle-bar::after {
    top: 0;
    transform: rotate(-45deg);
  }

  nav {
    position: fixed;
    top: var(--header-height);
    left: 0;
    right: 0;
    z-index: 999;
    display: none;
    flex-direction: column;
    align-items: stretch;
    gap: 0;
    padding: 12px 16px 20px;
    background: rgba(13, 13, 13, 0.98);
    border-bottom: 1px solid var(--border);
  }

  nav.open {
    display: flex;
  }

  nav a {
    width: 100%;
    justify-content: flex-start;
    padding: 16px 4px;
    font-size: 18px;
    border-bottom: 1px solid var(--border);
    border-radius: 0;
    min-height: 0;
  }

  nav a:last-child {
    border-bottom: none;
  }

  .hero {
    min-height: auto;
    padding: 24px 20px 28px;
  }

  .hero img {
    width: 100%;
    max-width: 620px;
  }

  .section {
    padding: 40px 20px;
  }

  .container {
    margin: 28px auto;
    padding: 0 16px;
  }

  footer {
    padding: 28px 16px;
  }
}