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

/* Base typography */
body {
  font-family: var(--font-body);
  line-height: 1.6;
  color: var(--color-text);
  background: var(--color-bg);
  -webkit-font-smoothing: antialiased;
}

/* App container */
#app {
  display: flex;
  flex-direction: column;
  max-width: var(--max-width);
  margin: 0 auto;
  padding: var(--space-8) var(--space-4);
  min-height: 100vh;
}

/* View switching: author display rules must not defeat the hidden attribute */
#app > section[hidden] {
  display: none !important;
}

/* Error state */
.error {
  color: var(--color-error);
  display: block !important;
  padding: var(--space-4);
  border: 1px solid var(--color-error);
  border-radius: var(--border-radius);
  background: #FFF5F0;
}

/* Buttons */
button {
  font-family: var(--font-body);
  font-size: 16px;
  font-weight: 500;
  padding: var(--space-3) var(--space-5);
  border: 1px solid var(--color-border);
  border-radius: var(--border-radius);
  background: var(--color-bg);
  cursor: pointer;
  transition: all var(--transition-fast);
}

button:hover {
  background: var(--color-border);
}

.btn-primary {
  background: var(--color-primary);
  color: #fff;
  border-color: var(--color-primary);
  width: 100%;
}

.btn-primary:hover {
  background: #333;
  transform: translateY(-1px);
  box-shadow: 0 4px 12px rgba(0,0,0,0.1);
}

/* Landing view */
#landing-view {
  display: flex;
  flex-direction: column;
  align-items: flex-start;
  text-align: left;
  flex: 1;
  padding-top: var(--space-10);
}

#landing-view h1 {
  font-family: var(--font-heading);
  font-size: 64px;
  font-weight: 400;
  line-height: 1.1;
  margin-bottom: var(--space-4);
  letter-spacing: -0.02em;
}

#landing-view .subtitle {
  font-size: 24px;
  color: var(--color-text-muted);
  margin-bottom: var(--space-2);
  max-width: 540px;
  line-height: 1.4;
}

#landing-view .meta {
  font-family: var(--font-mono);
  font-size: 13px;
  color: var(--color-text-light);
  margin-bottom: var(--space-8);
  text-transform: uppercase;
  letter-spacing: 0.05em;
}

#landing-view #start-btn {
  max-width: 300px;
}

/* Responsive — Tablet */
@media (max-width: 768px) {
  #app {
    padding: var(--space-6) var(--space-3);
  }

  #landing-view {
    padding-top: var(--space-6);
  }

  #landing-view h1 {
    font-size: 44px;
  }

  #landing-view .subtitle {
    font-size: 20px;
    margin-bottom: var(--space-6);
  }

  #landing-view .meta {
    margin-bottom: var(--space-6);
  }
}

/* Responsive — Mobile */
@media (max-width: 480px) {
  #app {
    padding: var(--space-4) var(--space-3);
  }

  #landing-view {
    padding-top: var(--space-4);
  }

  #landing-view h1 {
    font-size: 32px;
    letter-spacing: -0.01em;
  }

  #landing-view .subtitle {
    font-size: 18px;
  }

  #landing-view #start-btn {
    max-width: 100%;
  }

  p {
    font-size: 16px;
  }
}