/* style.css */
:root {
  --font-sans: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, "Noto Sans JP", sans-serif;
  
  /* Light Theme variables */
  --bg-color: #fcfcfd;
  --text-color: #1a1a1e;
  --accent-color: #4f46e5;
  --accent-hover: #4338ca;
  --card-bg: #ffffff;
  --card-border: #e4e4e7;
  --card-hover-bg: #f4f4f5;
  --input-bg: #ffffff;
  --input-border: #ccc;
  --meta-color: #71717a;
}

[data-theme="dark"] {
  /* Dark Theme variables */
  --bg-color: #121214;
  --text-color: #f4f4f5;
  --accent-color: #818cf8;
  --accent-hover: #6366f1;
  --card-bg: #1c1c1f;
  --card-border: #2e2e33;
  --card-hover-bg: #27272a;
  --input-bg: #242427;
  --input-border: #444;
  --meta-color: #a1a1aa;
}

* {
  box-sizing: border-box;
}

body {
  font-family: var(--font-sans);
  background-color: var(--bg-color);
  color: var(--text-color);
  max-width: 600px;
  margin: 0 auto;
  padding: 24px 16px;
  line-height: 1.6;
  transition: background-color 0.3s ease, color 0.3s ease;
}

/* Header & Theme Switcher */
header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: 32px;
  border-bottom: 1px solid var(--card-border);
  padding-bottom: 12px;
}

h1 {
  font-size: 1.5rem;
  margin: 0;
}

/* Buttons */
button, .btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  background-color: var(--accent-color);
  color: #fff;
  border: none;
  border-radius: 6px;
  padding: 10px 18px;
  font-size: 1rem;
  font-weight: 500;
  cursor: pointer;
  transition: background-color 0.2s, transform 0.1s;
  text-decoration: none;
  -webkit-tap-highlight-color: transparent;
}

button:hover, .btn:hover {
  background-color: var(--accent-hover);
}

button:active, .btn:active {
  transform: scale(0.98);
}

/* Secondary Button Mode */
button.secondary, .btn.secondary {
  background-color: transparent;
  color: var(--text-color);
  border: 1px solid var(--card-border);
}

button.secondary:hover, .btn.secondary:hover {
  background-color: var(--card-hover-bg);
}

/* Theme toggle button styling */
#themeToggle {
  background: none;
  border: 1px solid var(--card-border);
  color: var(--text-color);
  font-size: 1.2rem;
  padding: 8px;
  border-radius: 50%;
  width: 40px;
  height: 40px;
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: center;
}

#themeToggle:hover {
  background-color: var(--card-hover-bg);
}

/* Subject Grid & Cards */
.subject-grid {
  display: grid;
  gap: 16px;
  margin-top: 24px;
}

.subject-card {
  display: flex;
  justify-content: space-between;
  align-items: center;
  background-color: var(--card-bg);
  border: 1px solid var(--card-border);
  border-radius: 8px;
  padding: 20px;
  text-decoration: none;
  color: inherit;
  transition: background-color 0.2s, border-color 0.2s, transform 0.2s;
  box-shadow: 0 1px 3px rgba(0,0,0,0.05);
}

.subject-card:hover {
  background-color: var(--card-hover-bg);
  border-color: var(--accent-color);
  transform: translateY(-2px);
}

.subject-info h2 {
  margin: 0 0 4px 0;
  font-size: 1.2rem;
}

.subject-info p {
  margin: 0;
  font-size: 0.85rem;
  color: var(--meta-color);
}

.arrow-icon {
  font-size: 1.2rem;
  color: var(--meta-color);
  transition: transform 0.2s, color 0.2s;
}

.subject-card:hover .arrow-icon {
  transform: translateX(4px);
  color: var(--accent-color);
}

/* Inputs & Pulldowns */
select {
  font-size: 1rem;
  font-family: inherit;
  padding: 8px 12px;
  border-radius: 6px;
  border: 1px solid var(--input-border);
  background-color: var(--input-bg);
  color: var(--text-color);
  max-width: 100%;
  cursor: pointer;
  outline: none;
  transition: border-color 0.2s;
}

select:focus {
  border-color: var(--accent-color);
}

input[type=text] {
  font-size: 1rem;
  font-family: inherit;
  padding: 10px 14px;
  border-radius: 6px;
  border: 1px solid var(--input-border);
  background-color: var(--input-bg);
  color: var(--text-color);
  width: 100%;
  box-sizing: border-box;
  outline: none;
  transition: border-color 0.2s;
}

input[type=text]:focus {
  border-color: var(--accent-color);
}

hr {
  border: none;
  border-top: 1px solid var(--card-border);
  margin: 20px 0;
}

/* Utility classes */
.meta {
  color: var(--meta-color);
  font-size: 0.85rem;
}

.contact-info {
  font-size: 0.7rem;
  color: var(--meta-color);
  opacity: 0.65;
  margin-top: 4px;
  text-align: center;
}

.hidden {
  display: none;
}