:root {
  --bg-canvas: hsl(210, 25%, 98%);
  --bg-surface: hsl(0, 0%, 100%);
  --bg-subtle: hsl(210, 20%, 95%);

  --text-primary: hsl(215, 28%, 14%);
  --text-secondary: hsl(215, 16%, 38%);
  --text-muted: hsl(215, 14%, 52%);

  --border-color: hsl(214, 20%, 89%);
  --border-hover: hsl(214, 22%, 76%);

  --accent-blue-bg: hsl(214, 65%, 95%);
  --accent-blue-text: hsl(216, 75%, 32%);
  --accent-blue-bar: hsl(216, 70%, 42%);

  --accent-teal-bg: hsl(172, 50%, 94%);
  --accent-teal-text: hsl(174, 76%, 24%);
  --accent-teal-bar: hsl(174, 68%, 32%);

  --accent-amber-bg: hsl(34, 75%, 94%);
  --accent-amber-text: hsl(26, 78%, 30%);
  --accent-amber-bar: hsl(26, 72%, 40%);

  --shadow-card: 0 2px 8px rgba(15, 23, 42, 0.04), 0 1px 2px rgba(15, 23, 42, 0.03);
  --shadow-card-hover: 0 10px 24px -4px rgba(15, 23, 42, 0.09), 0 4px 8px -2px rgba(15, 23, 42, 0.04);

  --font-sans: 'Plus Jakarta Sans', 'Noto Sans JP', -apple-system, BlinkMacSystemFont, sans-serif;
  --font-mono: 'JetBrains Mono', ui-monospace, SFMono-Regular, Menlo, monospace;
}

*,
*::before,
*::after {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

body {
  font-family: var(--font-sans);
  background-color: var(--bg-canvas);
  color: var(--text-primary);
  line-height: 1.6;
  min-height: 100vh;
  display: flex;
  flex-direction: column;
  -webkit-font-smoothing: antialiased;
}

.container {
  width: 100%;
  max-width: 980px;
  margin: 0 auto;
  padding: 0 1.25rem;
}

/* Header */
.site-header {
  background-color: var(--bg-surface);
  border-bottom: 1px solid var(--border-color);
  padding: 1rem 0;
}

.header-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.brand {
  display: inline-flex;
  align-items: center;
  gap: 0.65rem;
  text-decoration: none;
  color: var(--text-primary);
}

.brand-icon {
  width: 2rem;
  height: 2rem;
  border-radius: 7px;
  background-color: hsl(192, 70%, 22%);
  color: #ffffff;
  display: inline-flex;
  align-items: center;
  justify-content: center;
}

.brand-title {
  font-size: 1.1rem;
  font-weight: 700;
  letter-spacing: -0.02em;
}

.brand-domain {
  font-family: var(--font-mono);
  font-size: 0.75rem;
  color: var(--text-muted);
  background-color: var(--bg-subtle);
  padding: 0.15rem 0.45rem;
  border-radius: 4px;
}

/* Main Content */
.main-content {
  flex: 1;
  display: flex;
  align-items: center;
  padding: 3rem 0;
}

.portal-intro {
  margin-bottom: 2rem;
}

.portal-heading {
  font-size: clamp(1.35rem, 2.5vw, 1.75rem);
  font-weight: 700;
  letter-spacing: -0.02em;
  margin-bottom: 0.35rem;
}

.portal-sub {
  font-size: 0.92rem;
  color: var(--text-secondary);
}

/* 3-Card Grid */
.tools-grid {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 1.25rem;
}

.tool-card {
  display: flex;
  flex-direction: column;
  justify-content: space-between;
  background-color: var(--bg-surface);
  border: 1px solid var(--border-color);
  border-radius: 12px;
  text-decoration: none;
  color: inherit;
  box-shadow: var(--shadow-card);
  overflow: hidden;
  transition: transform 0.16s ease, box-shadow 0.16s ease, border-color 0.16s ease;
  cursor: pointer;
}

.tool-card:hover {
  transform: translateY(-3px);
  box-shadow: var(--shadow-card-hover);
  border-color: var(--border-hover);
}

.tool-card-bar {
  height: 4px;
  width: 100%;
}

.tool-card[data-theme='blue'] .tool-card-bar {
  background-color: var(--accent-blue-bar);
}
.tool-card[data-theme='teal'] .tool-card-bar {
  background-color: var(--accent-teal-bar);
}
.tool-card[data-theme='amber'] .tool-card-bar {
  background-color: var(--accent-amber-bar);
}

.tool-card-content {
  padding: 1.4rem 1.35rem 1.2rem;
  display: flex;
  flex-direction: column;
  gap: 0.65rem;
}

.tool-meta {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 0.5rem;
}

.tool-badge {
  font-size: 0.73rem;
  font-weight: 700;
  padding: 0.18rem 0.55rem;
  border-radius: 5px;
}

.tool-card[data-theme='blue'] .tool-badge {
  background-color: var(--accent-blue-bg);
  color: var(--accent-blue-text);
}
.tool-card[data-theme='teal'] .tool-badge {
  background-color: var(--accent-teal-bg);
  color: var(--accent-teal-text);
}
.tool-card[data-theme='amber'] .tool-badge {
  background-color: var(--accent-amber-bg);
  color: var(--accent-amber-text);
}

.tool-path {
  font-family: var(--font-mono);
  font-size: 0.75rem;
  color: var(--text-muted);
}

.tool-name {
  font-size: 1.35rem;
  font-weight: 700;
  letter-spacing: -0.02em;
  color: var(--text-primary);
  line-height: 1.25;
}

.tool-jp {
  font-size: 0.9rem;
  font-weight: 600;
  color: var(--text-secondary);
}

.tool-desc {
  font-size: 0.84rem;
  color: var(--text-secondary);
  line-height: 1.6;
  margin-top: 0.15rem;
}

.tool-card-action {
  padding: 0.85rem 1.35rem;
  border-top: 1px solid var(--border-color);
  background-color: var(--bg-canvas);
  display: flex;
  align-items: center;
  justify-content: space-between;
  font-size: 0.85rem;
  font-weight: 600;
  color: var(--text-primary);
  transition: background-color 0.15s ease;
}

.tool-card:hover .tool-card-action {
  background-color: var(--bg-subtle);
}

.arrow-icon {
  transition: transform 0.15s ease;
}

.tool-card:hover .arrow-icon {
  transform: translateX(3px);
}

/* Footer */
.site-footer {
  border-top: 1px solid var(--border-color);
  background-color: var(--bg-surface);
  padding: 1.1rem 0;
  font-size: 0.76rem;
  color: var(--text-muted);
  text-align: center;
}

@media (max-width: 820px) {
  .main-content {
    padding: 2rem 0;
  }
  .tools-grid {
    grid-template-columns: 1fr;
  }
}