:root{
  --text: #222;
  --bg: #fafafa;
  --muted: #666;
  --max: 860px;
  --radius: 10px;
}

body {
  margin: 0;
  font-family: -apple-system, BlinkMacSystemFont, "Helvetica Neue", sans-serif;
  line-height: 1.7;
  color: var(--text);
  background: var(--bg);
}

.hero {
  position: relative;
  padding: 86px 20px;
  color: #fff;
  text-align: center;
  overflow: hidden;
}

.hero--image{
  background-image: url("../img/header_bg.jpg");
  background-size: cover;
  background-position: center 15%;
  background-repeat: no-repeat;
}

.hero__overlay{
  position: absolute;
  inset: 0;
  background: rgba(0,0,0,0.55); /* 文字が読めるように暗幕 */
}

.hero__inner{
  position: relative;
  z-index: 1;
  max-width: var(--max);
  margin: 0 auto;
}

.hero h1 {
  font-size: 34px;
  margin: 0 0 10px;
  letter-spacing: 0.02em;
}

.tagline {
  opacity: 0.9;
  margin: 0 0 16px;
}

.hero .sponsor {
  color: #fff;
  opacity: 0.95;
  font-size: 15px;
  font-weight: 500;
  margin: 0 0 26px;
  letter-spacing: 0.01em;
}

.hero__note{
  margin: 16px 0 0;
  font-size: 14px;
  opacity: 0.85;
}

main {
  display: block;
}

.section {
  padding: 40px 20px;
  max-width: var(--max);
  margin: 0 auto;
}

.section h2 {
  margin: 0 0 18px;
  font-size: 22px;
}

ul {
  padding-left: 20px;
}

.center {
  text-align: center;
}

.btn {
  display: inline-block;
  background: #00c300;
  color: white;
  padding: 14px 24px;
  border-radius: 8px;
  text-decoration: none;
  font-weight: 700;
  transition: 0.2s;
}

.btn:hover {
  opacity: 0.85;
}

.btn.large {
  font-size: 18px;
  padding: 18px 32px;
}

/* プロフィール */
.profile{
  display: grid;
  grid-template-columns: 120px 1fr;
  gap: 18px;
  padding: 18px;
  background: #fff;
  border-radius: var(--radius);
  border: 1px solid #eee;
  margin-bottom: 24px;
}

.profile:last-child{
  margin-bottom: 0;
}

.profile__avatar{
  width: 120px;
  height: 120px;
  border-radius: 999px;
  object-fit: cover;
  background: #ddd;
}

.profile__name{
  margin: 0 0 4px;
  font-size: 18px;
}

.profile__role{
  margin: 0 0 10px;
  color: var(--muted);
  font-size: 14px;
}

.profile__text{
  margin: 0 0 12px;
}

.profile__links{
  list-style: none;
  padding: 0;
  margin: 0;
  display: flex;
  gap: 16px;
}

.profile__links a{
  color: #1a73e8;
  text-decoration: none;
  font-size: 20px;
  display: flex;
  align-items: center;
  justify-content: center;
  width: 36px;
  height: 36px;
  border-radius: 6px;
  transition: 0.2s;
}

.profile__links a:hover{
  background: rgba(26, 115, 232, 0.1);
  transform: translateY(-1px);
}

/* Googleマップ */
.map-container {
  margin-top: 24px;
  border-radius: var(--radius);
  overflow: hidden;
  box-shadow: 0 2px 8px rgba(0,0,0,0.1);
}

.map-container iframe {
  width: 100%;
  height: 400px;
  display: block;
}

/* 交流会の特徴 */
.features {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
  gap: 24px;
  margin: 32px 0;
}

.feature {
  background: #fff;
  padding: 20px;
  border-radius: var(--radius);
  border: 1px solid #eee;
  box-shadow: 0 2px 4px rgba(0,0,0,0.05);
}

.feature h3 {
  margin: 0 0 12px;
  font-size: 16px;
  color: var(--text);
}

.feature p {
  margin: 0;
  color: var(--muted);
  font-size: 14px;
  line-height: 1.6;
}

footer {
  text-align: center;
  padding: 30px 20px;
  font-size: 14px;
  color: var(--muted);
}

.sponsor {
  font-weight: 600;
  color: var(--text);
  margin-bottom: 8px !important;
}

/* スマホ最適化 */
@media (max-width: 640px){
  .hero{
    padding: 70px 18px;
  }
  .hero h1{
    font-size: 28px;
  }
  .profile{
    grid-template-columns: 1fr;
  }
  .profile__avatar{
    margin: 0 auto;
  }
  .profile__links{
    justify-content: center;
    flex-wrap: wrap;
  }
  .features {
    grid-template-columns: 1fr;
    gap: 16px;
    margin: 24px 0;
  }
  .feature {
    padding: 16px;
  }
  .map-container iframe {
    height: 250px;
  }
}