:root {
  --bg-color: #0f172a;
  --card-bg: #1e293b;
  --text-color: #f8fafc;
  --text-muted: #94a3b8;
  --primary-color: #38bdf8;
  --primary-hover: #0ea5e9;
  --border-color: #334155;
  --radius: 8px;
  --font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
}

body {
  margin: 0;
  padding: 0;
  background-color: var(--bg-color);
  color: var(--text-color);
  font-family: var(--font-family);
  display: flex;
  flex-direction: column;
  min-height: 100vh;
}

header {
  background-color: var(--card-bg);
  border-bottom: 1px solid var(--border-color);
  padding: 0.75rem 1.5rem;
  display: flex;
  align-items: center;
  gap: 1rem;
}

.logo a {
  color: var(--text-color);
  text-decoration: none;
  font-weight: 700;
  font-size: 1.1rem;
}

main {
  flex: 1;
  max-width: 900px;
  width: 100%;
  margin: 2rem auto;
  padding: 0 1rem;
  box-sizing: border-box;
}

footer {
  text-align: center;
  padding: 1.5rem;
  border-top: 1px solid var(--border-color);
  color: var(--text-muted);
  font-size: 0.875rem;
}

/* 共通コンポーネント */
.btn {
  background-color: var(--primary-color);
  color: #0f172a;
  font-weight: 600;
  border: none;
  border-radius: var(--radius);
  padding: 0.75rem 1.5rem;
  cursor: pointer;
  transition: background-color 0.2s;
  font-size: 1rem;
}

.btn:hover {
  background-color: var(--primary-hover);
}

.btn:disabled {
  background-color: var(--border-color);
  color: var(--text-muted);
  cursor: not-allowed;
}

.dropzone {
  border: 2px dashed var(--border-color);
  border-radius: var(--radius);
  padding: 3rem 1.5rem;
  text-align: center;
  background-color: rgba(30, 41, 59, 0.5);
  cursor: pointer;
  transition: border-color 0.2s, background-color 0.2s;
}

.dropzone:hover, .dropzone.dragover {
  border-color: var(--primary-color);
  background-color: rgba(56, 189, 248, 0.05);
}

.dropzone p {
  color: var(--text-muted);
  margin-top: 0.5rem;
}

/* トップページ用スタイル */
.hero {
  text-align: center;
  margin-bottom: 3rem;
}
.hero h1 {
  font-size: 2.25rem;
  margin-bottom: 0.75rem;
}
.hero p {
  color: var(--text-muted);
  font-size: 1.1rem;
}
.category-section {
  margin-bottom: 3rem;
}
.category-title {
  font-size: 1.35rem;
  margin-bottom: 0.4rem;
  color: var(--text-color);
  border-left: 4px solid var(--primary-color);
  padding-left: 0.75rem;
}
.category-desc {
  color: var(--text-muted);
  font-size: 0.9rem;
  margin-bottom: 1.25rem;
}
.tool-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(260px, 1fr));
  gap: 1.5rem;
}
.tool-card {
  background-color: var(--card-bg);
  border: 1px solid var(--border-color);
  border-radius: var(--radius);
  padding: 1.5rem;
  text-decoration: none;
  color: inherit;
  display: flex;
  flex-direction: column;
  transition: transform 0.2s, border-color 0.2s;
}
.tool-card:hover {
  transform: translateY(-4px);
  border-color: var(--primary-color);
}
.tool-card-icon {
  font-size: 2rem;
  margin-bottom: 1rem;
}
.tool-card-title {
  font-size: 1.15rem;
  font-weight: 600;
  margin-bottom: 0.5rem;
}
.tool-card-desc {
  color: var(--text-muted);
  font-size: 0.875rem;
  line-height: 1.5;
  flex: 1;
}
.tool-card-tags {
  margin-top: 1rem;
  display: flex;
  gap: 0.5rem;
  flex-wrap: wrap;
}
.tool-tag {
  background-color: rgba(255, 255, 255, 0.05);
  font-size: 0.75rem;
  padding: 0.2rem 0.5rem;
  border-radius: 4px;
  color: var(--text-muted);
}

/* ========================================================
   ハンバーガーメニュー・ドロワーサイドバー スタイル
   ======================================================== */
.nav-menu-btn {
  background: none;
  border: none;
  padding: 0.4rem;
  cursor: pointer;
  display: flex;
  flex-direction: column;
  justify-content: center;
  gap: 5px;
  width: 32px;
  height: 32px;
  border-radius: 6px;
  transition: background 0.2s;
}
.nav-menu-btn:hover {
  background: rgba(255, 255, 255, 0.08);
}
.nav-menu-btn span {
  display: block;
  width: 20px;
  height: 2px;
  background-color: var(--text-color);
  border-radius: 2px;
  margin: 0 auto;
}

/* 背景オーバーレイ */
.drawer-overlay {
  position: fixed;
  top: 0;
  left: 0;
  width: 100vw;
  height: 100vh;
  background: rgba(0, 0, 0, 0.65);
  backdrop-filter: blur(2px);
  z-index: 998;
  opacity: 0;
  visibility: hidden;
  transition: opacity 0.3s ease, visibility 0.3s ease;
}
.drawer-overlay.active {
  opacity: 1;
  visibility: visible;
}

/* サイドバー本体 */
.nav-drawer {
  position: fixed;
  top: 0;
  left: 0;
  width: 300px;
  max-width: 85vw;
  height: 100vh;
  background-color: #131d31;
  border-right: 1px solid var(--border-color);
  z-index: 999;
  transform: translateX(-100%);
  transition: transform 0.3s cubic-bezier(0.16, 1, 0.3, 1);
  display: flex;
  flex-direction: column;
  box-shadow: 10px 0 25px rgba(0, 0, 0, 0.5);
}
.nav-drawer.active {
  transform: translateX(0);
}

.drawer-header {
  padding: 1rem 1.25rem;
  display: flex;
  align-items: center;
  justify-content: space-between;
  border-bottom: 1px solid var(--border-color);
}
.drawer-header-title {
  font-weight: 700;
  font-size: 1rem;
  color: var(--text-color);
  display: flex;
  align-items: center;
  gap: 0.5rem;
}
.drawer-close-btn {
  background: none;
  border: none;
  color: var(--text-muted);
  font-size: 1.25rem;
  cursor: pointer;
  padding: 0.2rem 0.5rem;
  border-radius: 4px;
}
.drawer-close-btn:hover {
  color: var(--text-color);
  background: rgba(255, 255, 255, 0.08);
}

.drawer-body {
  flex: 1;
  overflow-y: auto;
  padding: 1rem 0.75rem;
}
.drawer-group {
  margin-bottom: 1.5rem;
}
.drawer-group-title {
  font-size: 0.75rem;
  text-transform: uppercase;
  color: var(--text-muted);
  letter-spacing: 0.05em;
  padding: 0 0.75rem 0.5rem;
  font-weight: 600;
}
.drawer-link {
  display: flex;
  align-items: center;
  gap: 0.75rem;
  padding: 0.65rem 0.75rem;
  color: var(--text-color);
  text-decoration: none;
  border-radius: 6px;
  font-size: 0.875rem;
  transition: background 0.15s, color 0.15s;
}
.drawer-link:hover {
  background: rgba(255, 255, 255, 0.06);
  color: var(--primary-color);
}
.drawer-link.current {
  background: rgba(56, 189, 248, 0.12);
  color: var(--primary-color);
  font-weight: 600;
}
.drawer-link-icon {
  font-size: 1.15rem;
  width: 22px;
  text-align: center;
  flex-shrink: 0;
}
.drawer-link-text {
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
}