body {
  
  padding: 20px;
  background: #f4f4f4;
  color: #222;
  font-family: Arial, sans-serif;
  font-size: 16px;  /* base size */
}
html {
  font-size: 100%;   /* 16px */
}

/* Dark mode */
body.dark {
  background: #121212;
  color: #eee;
}

header {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 10px;
  margin-bottom: 20px;
  position: relative;
}

.logo {
  width: 70px;
  height: auto;
}

#darkToggle {
  position: absolute;
  right: 0;
  top: 10px;
  padding: 8px;
  border-radius: 8px;
  background: #ddd;
}


body.dark #darkToggle {
  background: #333;
  color: white;
}

.controls {
  display: flex;
  gap: 10px;
  margin-bottom: 20px;
}

.topic-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(260px, 1fr));
  gap: 15px;
}

.topic-card {
  background: white;
  padding: 20px;
  border-radius: 12px;
  border: 1px solid #ddd;
  transition: 0.2s ease;

}

.topic-card:hover {
  transform: translateY(-5px);
}

body.dark .topic-card {
  background: #1e1e1e;
  border-color: #333;
}

.topic-card h2 {
  margin-bottom: 10px;
}

a {
  color: #2d7df4;
}

.back-btn {
  text-decoration: none;
  font-size: 18px;
}
.topic-card p, #topic-details p {
  line-height: 1.7;   /* more space between lines */
  margin-bottom: 12px; /* space between paragraphs */
}
.topic-card, #topic-details {
  font-size: 1rem;    /* 1rem = 16px */
}
/* Font size buttons */
button.font-btn {
  padding: 10px 18px;
  margin: 5px 5px 20px 0;
  font-size: 1rem;
  font-weight: bold;
  border: none;
  border-radius: 8px;
  cursor: pointer;
  background-color: #2d7df4;
  color: white;
  transition: background 0.2s ease, transform 0.1s ease;
}

button.font-btn:hover {
  background-color: #1a5ed8;
  transform: translateY(-2px);
}

body.dark button.font-btn {
  background-color: #5555ff;
}

body.dark button.font-btn:hover {
  background-color: #4444cc;
}

/* Controls container */
.controls {
  display: flex;
  gap: 15px;
  margin-bottom: 20px;
  flex-wrap: wrap; /* allows wrapping on smaller screens */
  justify-content: center;
}

/* Search input */
#search {
  flex: 1;                /* take remaining space */
  min-width: 250px;       /* don’t shrink too much */
  padding: 12px 18px;     /* bigger clickable area */
  font-size: 1.1rem;      /* slightly bigger text */
  border: 1px solid #ccc;
  border-radius: 12px;
  outline: none;
  transition: border 0.2s ease, box-shadow 0.2s ease;
}

#search:focus {
  border-color: #2d7df4;
  box-shadow: 0 0 6px rgba(45, 125, 244, 0.4);
}

/* Category select */
#categoryFilter {
  padding: 12px 18px;
  font-size: 1.1rem;
  border-radius: 12px;
  border: 1px solid #ccc;
  cursor: pointer;
  min-width: 180px;
}

body.dark #search,
body.dark #categoryFilter {
  background: #1e1e1e;
  color: #eee;
  border-color: #333;
}


/* Footer styling */
footer {
  text-align: center;
  padding: 20px;
  margin-top: 40px;
  font-size: 0.95rem;
  color: #555;
  border-top: 1px solid #ddd;
  background: #f9f9f9;
  border-radius: 12px 12px 0 0;
}

body.dark footer {
  color: #ccc;
  border-color: #333;
  background: #1a1a1a;
}