/* --- テーマ変数定義 --- */
:root {
  /* デフォルトはダークテーマ */
  --bg-color: #222;
  --text-color: #eee;
  --title-color: #fff;
  --shadow-color-heavy: rgba(0,0,0,0.7);
  --shadow-color-medium: rgba(0,0,0,0.5);
  --input-bg-gradient-start: #555;
  --input-bg-gradient-end: #333;
  --input-border-color: #666;
  --button-text-color: #222;
  --button-bg-gradient-start: #bbb;
  --button-bg-gradient-end: #888;
  --button-shadow-color: #555;
  --top-bar-bg: rgba(60, 60, 60, 0.85);
  --iframe-bg: #fff;
}

body.light-theme {
  /* ライトテーマ用の変数上書き */
  --bg-color: #f0f2f5;
  --text-color: #1c1e21;
  --title-color: #0056b3;
  --shadow-color-heavy: rgba(0,0,0,0.15);
  --shadow-color-medium: rgba(0,0,0,0.1);
  --input-bg-gradient-start: #fff;
  --input-bg-gradient-end: #f5f5f5;
  --input-border-color: #ccc;
  --button-text-color: #fff;
  --button-bg-gradient-start: #007bff;
  --button-bg-gradient-end: #0056b3;
  --button-shadow-color: #00418a;
  --top-bar-bg: rgba(255, 255, 255, 0.85);
  --iframe-bg: #fff;
}

/* --- 基本スタイル --- */
body {
  margin: 0;
  font-family: sans-serif;
  background: var(--bg-color);
  color: var(--text-color);
  transition: background-color 0.3s, color 0.3s;
}

/* --- トップページ（大きなフォーム）のスタイル --- */
#top-large {
  text-align: center;
  margin-top: 100px;
  transition: opacity 0.3s ease, transform 0.3s ease;
}
#top-large h1 {
  font-size: 64px;
  margin-bottom: 40px;
  color: var(--title-color);
  text-shadow: 0 3px 6px var(--shadow-color-heavy);
}
#top-large input {
  width: 400px;
  padding: 12px;
  font-size: 18px;
  border-radius: 8px;
  transition: all 0.2s ease;
  background: linear-gradient(to bottom, var(--input-bg-gradient-start), var(--input-bg-gradient-end));
  color: var(--text-color);
  border: 1px solid var(--input-border-color);
  box-shadow: inset 0 3px 6px var(--shadow-color-heavy);
}
#top-large input:focus {
  border-color: #aaa;
  outline: none;
}
#top-large button {
  padding: 12px 20px;
  font-size: 18px;
  border-radius: 8px;
  font-weight: bold;
  cursor: pointer;
  transition: all 0.2s ease;
  position: relative;
  margin-left: 8px;
  background: linear-gradient(to bottom, var(--button-bg-gradient-start), var(--button-bg-gradient-end));
  color: var(--button-text-color);
  border: 1px solid var(--button-shadow-color);
  box-shadow: 0 6px 0 var(--button-shadow-color), 0 8px 12px var(--shadow-color-medium);
}

/* --- ボタンのホバー＆クリックエフェクト --- */
#top-large button:hover, #top-small button:hover {
    transform: translateY(-1px);
    box-shadow: 0 8px 0 var(--button-shadow-color), 0 10px 15px var(--shadow-color-medium);
}
#top-large button:active, #top-small button:active {
    transform: translateY(2px);
    box-shadow: inset 0 3px 6px rgba(0,0,0,0.4);
}

/* --- サイト表示中の上部バーのスタイル --- */
#top-small {
  position: fixed;
  top: -60px;
  left: 0;
  width: 100%;
  display: flex;
  justify-content: center;
  align-items: center;
  gap: 8px;
  padding: 6px 12px;
  box-shadow: 0 2px 6px var(--shadow-color-heavy);
  transition: top 0.3s ease;
  z-index: 1000;
  background: var(--top-bar-bg);
  backdrop-filter: blur(6px);
  border-bottom: 1px solid rgba(128,128,128,0.2);
  height: 48px;
  box-sizing: border-box;
}
.top-small-content {
  display: flex;
  width: 100%;
  max-width: 800px;
  gap: 8px;
  align-items: center;
}
#top-small input {
  flex: 1;
  height: 36px;
  padding: 0 12px;
  font-size: 16px;
  border-radius: 8px;
  border: 1px solid var(--input-border-color);
  background: linear-gradient(to bottom, var(--input-bg-gradient-end), var(--input-bg-gradient-start));
  color: var(--text-color);
  transition: all 0.2s ease;
}
#top-small input:focus {
  border-color: #ccc;
  outline: none;
}
#top-small button {
  height: 36px;
  padding: 0 16px;
  font-size: 16px;
  font-weight: bold;
  border-radius: 8px;
  border: 1px solid var(--button-shadow-color);
  background: linear-gradient(to bottom, var(--button-bg-gradient-start), var(--button-bg-gradient-end));
  color: var(--button-text-color);
  box-shadow: 0 4px 0 var(--button-shadow-color), 0 5px 8px var(--shadow-color-medium);
  cursor: pointer;
  transition: all 0.2s ease;
  position: relative;
}

/* --- テーマ切り替えスイッチのスタイル --- */
.theme-switch {
  position: relative;
  width: 50px;
  height: 26px;
  background-color: var(--input-bg-gradient-end);
  border: 1px solid var(--input-border-color);
  border-radius: 13px;
  cursor: pointer;
  z-index: 1001;
  flex-shrink: 0;
}
.theme-switch-slider {
  position: absolute;
  top: 2px;
  left: 2px;
  width: 20px;
  height: 20px;
  background-color: var(--button-bg-gradient-start);
  border-radius: 50%;
  transition: transform 0.3s;
}
body.light-theme .theme-switch-slider {
  transform: translateX(24px);
}
.theme-switch-top {
  position: fixed;
  top: 12px;
  right: 12px;
  transition: opacity 0.3s;
}
.theme-switch-top.hidden {
  opacity: 0;
  pointer-events: none;
}

/* --- コンテンツ表示エリアとバージョンラベル --- */
#content {
  visibility: hidden;
  opacity: 0;
  transition: opacity 0.3s ease;
  height: 100vh;
  box-sizing: border-box;
}
#content.visible {
  visibility: visible;
  opacity: 1;
}
#content > div {
  width: 100%;
  height: 100%;
  border: none;
  background: var(--iframe-bg);
  overflow: auto;
}
.version-label {
  position: fixed;
  bottom: 10px;
  right: 14px;
  font-size: 14px;
  color: rgba(128, 128, 128, 0.5);
  pointer-events: none;
  user-select: none;
  z-index: 1002;
}