client/src/utils/theme.js

export const applyTheme = (theme) => {
  const root = document.documentElement;
  
  if (theme === 'dark') {
    root.classList.add('dark');
  } else {
    root.classList.remove('dark');
  }
  
  // Save to localStorage
  localStorage.setItem('theme', theme);
};

export const getInitialTheme = () => {
  const savedTheme = localStorage.getItem('theme');
  const prefersDark = window.matchMedia && 
    window.matchMedia('(prefers-color-scheme: dark)').matches;
  
  if (savedTheme) {
    return savedTheme;
  }
  
  return prefersDark ? 'dark' : 'light';
};