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

body {
  margin: 0;
  font-family: "Inter", "Hiragino Kaku Gothic ProN", sans-serif;
  background: #f9fafb;
  color: #1f2937;
}

a {
  text-decoration: none;
  color: inherit;
}

h1, h2, p {
  margin: 0;
}

/* ===== ヘッダー ===== */
.site-header {
  position: relative;
  text-align: center;
  padding: 80px 32px;
  background: linear-gradient(135deg, #e0e7ff, #ffffff);
  overflow: hidden;
}

.site-header h1 {
  font-size: 2.6rem;

}

.site-header p {
  font-size: 1.2rem;
  color: #6366f1;
}

/* ===== ふわふわAI画像 ===== */
#aiImage {
  width: 120px;
  position: absolute;
  top: 20px;
  left: 50%;
  transform: translateX(-50%);
  animation: floatAI 4s ease-in-out infinite;
}

@keyframes floatAI {
  0% { transform: translate(-50%, 0); }
  50% { transform: translate(-50%, -14px); }
  100% { transform: translate(-50%, 0); }
}

#aiImage.talking {
  filter: drop-shadow(0 0 14px rgba(255,105,180,0.8));
}

/* ===== レイアウト ===== */
.container {
  max-width: 1100px;
  margin: 0 auto;
  padding: 40px 20px;
}

/* ===== カード ===== */
.card-area {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(240px, 1fr));
  gap: 32px;
  margin-bottom: 80px;
}

.student-card {
  position: relative;
  padding: 38px 28px 32px;
  border-radius: 26px;
  background: linear-gradient(135deg, #ffffff, #f1f5f9);
  box-shadow: 0 12px 30px rgba(0,0,0,0.08);
  transition: transform .3s ease, box-shadow .3s ease;
  cursor: pointer;
}

.student-card:hover {
  transform: translateY(-8px);
  box-shadow: 0 22px 44px rgba(99,102,241,0.25);
}

.student-card .number {
  position: absolute;
  top: 18px;
  right: 22px;
  font-size: 2.6rem;
  font-weight: bold;
  color: rgba(99,102,241,0.18);
}

.student-card h2 {
  margin: 40px 0 10px;
  font-size: 1.35rem;
}

.student-card p {
  font-size: 0.95rem;
  color: #6366f1;
}

/* ===== 輪っかAI ===== */
#circle-ai {
  position: relative;
  width: 220px;
  height: 220px;
  margin: 40px auto 20px;
}

.circle {
  position: absolute;
  inset: 0;
  border-radius: 50%;
  border: 3px solid #ec4899;
  animation: circleIdle 3s ease-in-out infinite;
}

.circle:nth-child(2) {
  inset: 20px;
  border-color: #a855f7;
}

.circle:nth-child(3) {
  inset: 40px;
  border-color: #6366f1;
}

.talking-circle .circle {
  animation: circleTalk .35s ease-in-out infinite;
}

@keyframes circleIdle {
  0%,100% { transform: scale(1); }
  50% { transform: scale(1.06); }
}

@keyframes circleTalk {
  0% { transform: scale(1); }
  50% { transform: scale(1.16); }
  100% { transform: scale(1); }
}

/* ===== 吹き出し ===== */
#speechText {
  text-align: center;
  min-height: 1.6em;
  font-size: 1.1rem;
  color: #ec4899;
  margin-bottom: 28px;
}

/* ===== 起動ボタン ===== */
#startVoice {
  display: block;
  margin: 0 auto 60px;
  padding: 12px 30px;
  border-radius: 999px;
  border: none;
  background: linear-gradient(135deg, #6366f1, #ec4899);
  color: #fff;
  font-size: 1rem;
  cursor: pointer;
}

/* ===== フッター ===== */
.site-footer {
  text-align: center;
  padding: 40px;
  font-size: .9rem;
  color: #6b7280;
}