:root {
  font-family: 'Inter', 'Segoe UI', system-ui, -apple-system, BlinkMacSystemFont, Avenir, Helvetica, Arial, sans-serif;
  line-height: 1.6;
  font-weight: 400;

  color-scheme: light;
  color: #222;
  background: #ffffff; /* 白背景 */
  background-attachment: fixed;

  font-synthesis: none;
  text-rendering: optimizeLegibility;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

a {
  font-weight: 500;
  color: #4756e6;
  text-decoration: inherit;
}
a:hover {
  color: #3a45d8;
}

body {
  margin: 0;
  display: flex;
  place-items: center;
  min-width: 320px;
  min-height: 100vh;
  position: relative;
  overflow-x: hidden;
  /* 柔らかいグラデーションのアクセントを淡く入れる */
  background-image: radial-gradient(1000px 400px at 10% 10%, rgba(102,126,234,0.04), transparent),
                    radial-gradient(800px 300px at 90% 90%, rgba(118,75,162,0.04), transparent);
}

#root {
  position: relative;
  z-index: 1;
  width: 100%;
}

h1 {
  font-size: 3.2em;
  line-height: 1.1;
  font-weight: 800;
  letter-spacing: -0.02em;
}

button {
  border-radius: 10px;
  border: 1px solid #eef0f6;
  padding: 0.6em 1.2em;
  font-size: 1em;
  font-weight: 600;
  font-family: inherit;
  background-color: #fff; /* 明るいボタン */
  color: #222;
  cursor: pointer;
  transition: all 0.18s ease;
  box-shadow: 0 6px 16px rgba(30,30,60,0.06);
}
button:hover {
  transform: translateY(-2px);
  border-color: #dfe6ff;
}
button:focus,
button:focus-visible {
  outline: 4px auto -webkit-focus-ring-color;
}

* {
  box-sizing: border-box;
}

input {
  font-family: inherit;
}

/* テーマスタイル */
/* デフォルトテーマ */
body.theme-default {
  background: #ffffff;
  color: #222;
  background-image: radial-gradient(1000px 400px at 10% 10%, rgba(102,126,234,0.04), transparent),
                    radial-gradient(800px 300px at 90% 90%, rgba(118,75,162,0.04), transparent);
}

/* ダークブルーテーマ */
body.theme-theme_dark_blue {
  background: linear-gradient(135deg, #0f2027 0%, #203a43 50%, #2c5364 100%);
  color: #e0f7ff;
  background-attachment: fixed;
}

body.theme-theme_dark_blue a {
  color: #5dade2;
}

body.theme-theme_dark_blue button {
  background-color: rgba(93, 173, 226, 0.2);
  color: #e0f7ff;
  border-color: rgba(93, 173, 226, 0.3);
}

/* パープルテーマ */
body.theme-theme_purple {
  background: linear-gradient(135deg, #1a0b2e 0%, #3d1f5c 50%, #5f3a87 100%);
  color: #e8d5ff;
  background-attachment: fixed;
}

body.theme-theme_purple a {
  color: #b794f6;
}

body.theme-theme_purple button {
  background-color: rgba(183, 148, 246, 0.2);
  color: #e8d5ff;
  border-color: rgba(183, 148, 246, 0.3);
}

/* グリーンテーマ */
body.theme-theme_green {
  background: linear-gradient(135deg, #0d3b2e 0%, #1b5e3f 50%, #2d8659 100%);
  color: #d4ffea;
  background-attachment: fixed;
}

body.theme-theme_green a {
  color: #6ee7b7;
}

body.theme-theme_green button {
  background-color: rgba(110, 231, 183, 0.2);
  color: #d4ffea;
  border-color: rgba(110, 231, 183, 0.3);
}

/* サンセットテーマ */
body.theme-theme_sunset {
  background: linear-gradient(135deg, #2d1b3d 0%, #6b3654 50%, #b8526b 100%);
  color: #ffe8e8;
  background-attachment: fixed;
}

body.theme-theme_sunset a {
  color: #ffa07a;
}

body.theme-theme_sunset button {
  background-color: rgba(255, 160, 122, 0.2);
  color: #ffe8e8;
  border-color: rgba(255, 160, 122, 0.3);
}

/* 桜テーマ */
body.theme-theme_cherry {
  background: linear-gradient(135deg, #fce4ec 0%, #f8bbd0 50%, #f48fb1 100%);
  color: #4a0e2e;
  background-attachment: fixed;
}

body.theme-theme_cherry a {
  color: #c2185b;
}

body.theme-theme_cherry button {
  background-color: rgba(244, 143, 177, 0.3);
  color: #4a0e2e;
  border-color: rgba(244, 143, 177, 0.4);
}

/* ミッドナイトテーマ */
body.theme-theme_midnight {
  background: linear-gradient(135deg, #0a1128 0%, #1c2541 50%, #2d3561 100%);
  color: #d4e4ff;
  background-attachment: fixed;
}

body.theme-theme_midnight a {
  color: #7c9aff;
}

body.theme-theme_midnight button {
  background-color: rgba(124, 154, 255, 0.2);
  color: #d4e4ff;
  border-color: rgba(124, 154, 255, 0.3);
}

/* 紅葉テーマ */
body.theme-theme_autumn {
  background: linear-gradient(135deg, #3e2723 0%, #6d4c41 50%, #8d6e63 100%);
  color: #fff3e0;
  background-attachment: fixed;
}

body.theme-theme_autumn a {
  color: #ffab91;
}

body.theme-theme_autumn button {
  background-color: rgba(255, 171, 145, 0.2);
  color: #fff3e0;
  border-color: rgba(255, 171, 145, 0.3);
}