:root {
  /* Brand Colors */
  --color-blue: #0083BF;
  --color-teal: #62B39B;
  --color-mustard: #C8CC53;
  --color-yellow: #FFC009;
  
  /* UI Colors */
  --ink-primary: #1A1A1A;
  --ink-secondary: #4A4A4A;
  --ink-muted: #8E8E93;
  --paper-white: #FFFFFF;
  --paper-off: #F9F9F9;
  --paper-warm: #F4F2EE;
  --border: rgba(0, 0, 0, 0.08);
  
  /* Typography */
  --font-serif: 'Shippori Mincho', "BIZ UDPMincho", "Hiragino Mincho ProN", serif;
  --font-sans: "Inter", "Helvetica Neue", "Arial", "Hiragino Sans", "Meiryo", sans-serif;
  
  /* Spacing */
  --container-max: 1200px;
  --section-padding: 100px 5%;
  --section-padding-mobile: 60px 5%;
}

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

body {
  font-family: var(--font-sans);
  color: var(--ink-primary);
  line-height: 1.6;
  background-color: var(--paper-white);
  -webkit-font-smoothing: antialiased;
}

h1, h2, h3, h4 {
  font-family: var(--font-serif);
  font-weight: 600;
  line-height: 1.3;
}

a {
  text-decoration: none;
  color: inherit;
  transition: opacity 0.3s ease;
}

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

.container {
  max-width: var(--container-max);
  margin: 0 auto;
  width: 100%;
}

section {
  padding: var(--section-padding);
}

@media (max-width: 768px) {
  section {
    padding: var(--section-padding-mobile);
  }
}

/* 共通ヘッダー・フッター・コンポーネントの基本スタイル */
header {
  padding: 20px 5%;
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  z-index: 100;
  display: flex;
  justify-content: space-between;
  align-items: center;
  transition: all 0.3s ease;
}

header::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 140%; /* 少し余裕を持たせてグラデーション */
  background: linear-gradient(to bottom, rgba(0,0,0,0.4) 0%, rgba(0,0,0,0) 100%);
  z-index: -1;
  pointer-events: none;
  transition: opacity 0.3s ease;
}

.header-scrolled::before {
  opacity: 0;
}

.header-scrolled {
  background: rgba(255, 255, 255, 0.95);
  backdrop-filter: blur(10px);
  position: fixed;
  box-shadow: 0 2px 20px rgba(0,0,0,0.05);
  padding: 10px 5%;
}

.logo { height: 40px; }
.logo img { height: 100%; width: auto; }

.nav-links { display: none; gap: 30px; }
@media (min-width: 768px) { .nav-links { display: flex; align-items: center; } }

.nav-links a {
  font-size: 0.9rem;
  font-weight: 500;
  transition: color 0.3s ease;
}

/* トップページおよび詳細ページ（ヒーローセクション上）の初期色 */
.page-home #main-header:not(.header-scrolled) .nav-links a,
.page-features #main-header:not(.header-scrolled) .nav-links a {
  color: white;
}

/* スクロール後、または詳細ページの基本色 */
#main-header.header-scrolled .nav-links a,
.page-features #main-header .nav-links a {
  color: var(--ink-secondary);
}

.btn-contact-nav {
  background: var(--color-blue);
  color: white !important;
  padding: 10px 24px;
  border-radius: 4px;
}

/* ログインボタン: outline スタイルでお問い合わせと差別化 */
.btn-login-nav {
  border: 1.5px solid var(--color-blue);
  color: var(--color-blue) !important;
  padding: 8px 22px;
  border-radius: 4px;
  background: transparent;
  transition: background 0.2s ease, color 0.2s ease;
}
.btn-login-nav:hover {
  background: var(--color-blue);
  color: white !important;
}
/* hero 上の白文字状態でも視認性を確保 */
.page-home #main-header:not(.header-scrolled) .nav-links a.btn-login-nav,
.page-features #main-header:not(.header-scrolled) .nav-links a.btn-login-nav {
  border-color: white;
  color: white !important;
}
.page-home #main-header:not(.header-scrolled) .nav-links a.btn-login-nav:hover,
.page-features #main-header:not(.header-scrolled) .nav-links a.btn-login-nav:hover {
  background: white;
  color: var(--color-blue) !important;
}

footer {
  padding: 80px 5%;
  background: #000;
  color: white;
  border-top: 1px solid #222;
}

.footer-content {
  display: flex;
  flex-direction: column;
  align-items: center;
  text-align: center;
}

.footer-nav {
  display: flex;
  gap: 30px;
  margin: 40px 0;
  flex-wrap: wrap;
  justify-content: center;
}

.footer-nav a { font-size: 0.9rem; opacity: 0.7; }
.copyright { font-size: 0.8rem; opacity: 0.4; }

/* --- Responsive Utilities --- */

/* スマホのみ表示 */
.sp-only { display: none !important; }
/* PCのみ表示 */
.pc-only { display: inline-block !important; }

@media (max-width: 767px) {
  .sp-only { display: inline-block !important; }
  .pc-only { display: none !important; }
}

/* スマホのみ改行（PCではスペースとして機能） */
.sp-br { display: none; }
@media (max-width: 767px) {
  .sp-br { display: block; content: ""; }
}