:root {
  --bg: #f5f5f7;
  --text: #1d1d1f;
  --btn-bg: #e8e8ed;
  --btn-text: #1d1d1f;
  --btn-border: #c7c7cc;
  --subtitle: #86868b;
}

body.dark {
  --bg: #1a1a2e;
  --text: #f0f0f5;
  --btn-bg: #2d2d44;
  --btn-text: #f0f0f5;
  --btn-border: #4a4a6a;
  --subtitle: #a0a0b0;
}

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

body {
  font-family: 'Inter', sans-serif;
  background: var(--bg);
  color: var(--text);
  min-height: 100vh;
  display: flex;
  flex-direction: column;
  transition: background 0.3s, color 0.3s;
}

header {
  display: flex;
  justify-content: flex-end;
  padding: 1.5rem 2rem;
}

.btn-toggle {
  font-family: 'Inter', sans-serif;
  font-weight: 500;
  font-size: 0.95rem;
  padding: 0.55rem 1.4rem;
  border-radius: 8px;
  border: 1.5px solid var(--btn-border);
  background: var(--btn-bg);
  color: var(--btn-text);
  cursor: pointer;
  transition: background 0.3s, color 0.3s, border-color 0.3s;
}

.btn-toggle:hover {
  opacity: 0.85;
}

main {
  flex: 1;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  text-align: center;
  padding: 2rem;
}

.subtitle {
  font-size: 1.1rem;
  font-weight: 400;
  color: var(--subtitle);
  letter-spacing: 0.05em;
  text-transform: uppercase;
  margin-bottom: 1rem;
  transition: color 0.3s;
}

.logo {
  font-family: 'Playfair Display', serif;
  font-weight: 600;
  font-size: 2.4rem;
  letter-spacing: 0.02em;
}