/* YAMA-COLOR LP — 野外観察手帳デザインシステム */
@import url('https://fonts.googleapis.com/css2?family=Noto+Sans+JP:wght@400;500;700;900&family=Noto+Serif+JP:wght@400;700&display=swap');

/* ===== Design Tokens ===== */
:root {
  --yc-forest:    #3A5C3B;
  --yc-forest-light: #4D7A4E;
  --yc-sky:       #2C6B8A;
  --yc-golden:    #C96A0A;
  --yc-parchment: #F4EFE6;
  --yc-ink:       #1C1C1A;
  --yc-stone:     #8A8278;
  --yc-ash:       #E9E4DC;
  --yc-earth:     #6B4A2A;

  /* Legacy aliases */
  --primary:       var(--yc-forest);
  --primary-light:  var(--yc-forest-light);
  --accent:        var(--yc-golden);
  --text:          var(--yc-ink);
  --text-light:    var(--yc-stone);
  --bg:            var(--yc-parchment);
  --bg-alt:        var(--yc-ash);
}

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

body {
  font-family: 'Noto Sans JP', -apple-system, BlinkMacSystemFont, sans-serif;
  line-height: 1.7;
  color: var(--yc-ink);
  background: var(--yc-parchment);
  overflow-x: hidden;
}

/* ===== Animations ===== */
@keyframes fadeInUp {
  from { opacity: 0; transform: translateY(30px); }
  to   { opacity: 1; transform: translateY(0); }
}
@keyframes float {
  0%, 100% { transform: translateY(0); }
  50%      { transform: translateY(-16px); }
}
@keyframes slideInLeft {
  from { opacity: 0; transform: translateX(-40px); }
  to   { opacity: 1; transform: translateX(0); }
}
@keyframes slideInRight {
  from { opacity: 0; transform: translateX(40px); }
  to   { opacity: 1; transform: translateX(0); }
}
@keyframes breathe {
  0%, 100% { opacity: 0.6; }
  50%      { opacity: 1; }
}

/* ===== Utilities ===== */
.container {
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 2rem;
}

.btn {
  padding: 0.85rem 2rem;
  border-radius: 50px;
  text-decoration: none;
  font-weight: 700;
  font-size: 1rem;
  transition: all 0.3s ease;
  display: inline-block;
  cursor: pointer;
  border: none;
}

.btn-primary {
  background: linear-gradient(135deg, var(--yc-forest) 0%, var(--yc-forest-light) 100%);
  color: white;
  box-shadow: 0 4px 15px rgba(58, 92, 59, 0.3);
}
.btn-primary:hover {
  transform: translateY(-3px);
  box-shadow: 0 8px 25px rgba(58, 92, 59, 0.4);
}

.btn-secondary {
  background: transparent;
  color: var(--yc-forest);
  border: 2px solid var(--yc-forest);
}
.btn-secondary:hover {
  background: var(--yc-forest);
  color: white;
}

.btn-golden {
  background: linear-gradient(135deg, var(--yc-golden) 0%, #E08020 100%);
  color: white;
  box-shadow: 0 4px 15px rgba(201, 106, 10, 0.3);
}
.btn-golden:hover {
  transform: translateY(-3px);
  box-shadow: 0 8px 25px rgba(201, 106, 10, 0.4);
}

/* ===== Header ===== */
.header {
  position: fixed;
  top: 0;
  width: 100%;
  background: rgba(244, 239, 230, 0.92);
  backdrop-filter: blur(12px);
  box-shadow: 0 1px 12px rgba(28, 28, 26, 0.06);
  z-index: 1000;
  transition: all 0.3s ease;
}
.header.scrolled {
  box-shadow: 0 2px 20px rgba(28, 28, 26, 0.12);
}

.nav {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 0.8rem 2rem;
  max-width: 1200px;
  margin: 0 auto;
}

.logo {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  font-family: 'Noto Serif JP', serif;
  font-size: 1.4rem;
  font-weight: 700;
  color: var(--yc-forest);
  text-decoration: none;
  letter-spacing: 0.05em;
}
.logo-icon {
  font-size: 1.6rem;
}
.logo-sub {
  font-size: 0.65rem;
  font-weight: 400;
  color: var(--yc-stone);
  display: block;
  letter-spacing: 0.15em;
}

.nav-menu {
  display: flex;
  list-style: none;
  gap: 2rem;
  align-items: center;
}
.nav-menu a {
  text-decoration: none;
  color: var(--yc-ink);
  font-weight: 500;
  font-size: 0.95rem;
  transition: color 0.3s;
  position: relative;
}
.nav-menu a:hover { color: var(--yc-forest); }
.nav-menu a::after {
  content: '';
  position: absolute;
  bottom: -4px;
  left: 0;
  width: 0;
  height: 2px;
  background: var(--yc-forest);
  transition: width 0.3s;
}
.nav-menu a:hover::after { width: 100%; }