/* === CSS Reset & Box Model === */
*,
*::before,
*::after {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

html {
  font-size: 16px; /* base for rem scaling */
  line-height: 1.5;
  -webkit-font-smoothing: antialiased;
  scroll-behavior: smooth;
}

body {
  font-family: 'Roboto', sans-serif;
  font-size: 1rem; /* 16px */
  background-color: #f9fafb;
  color: #111827;
}

/* === Theme Colors === */
:root {
  --color-primary: #3b82f6;
  --color-primary-dark: #2563eb;
  --color-secondary: #f59e0b;
  --color-background: #ffffff;
  --color-surface: #f3f4f6;
  --color-border: #d1d5db;
  --color-muted: #6b7280;
  --color-error: #dc2626;
}

/* === Typography Scale === */
h1 {
  font-size: 2rem;       /* 32px */
  font-weight: 500;
  margin-bottom: 0.5em;
}

h2 {
  font-size: 1.5rem;     /* 24px */
  font-weight: 500;
}

h3 {
  font-size: 1.25rem;    /* 20px */
  font-weight: 500;
}

p, a, span, li {
  font-size: 1rem;       /* 16px */
  color: inherit;
}

small {
  font-size: 0.875rem;
  color: var(--color-muted);
}

/* === Links === */
a {
  color: var(--color-primary);
  text-decoration: none;
}
a:hover {
  text-decoration: underline;
}

/* === Forms === */
input[type="text"],
input[type="password"],
input[type="email"],
input[type="number"],
input[type="search"],
input[type="tel"],
input[type="url"],
textarea,
select {
  width: 100%;
  padding: 0.6rem 1rem;
  border: 1px solid var(--color-border);
  border-radius: 6px;
  font-size: 1rem;
}

input:focus,
textarea:focus,
select:focus {
  outline: none;
  border-color: var(--color-primary);
  box-shadow: 0 0 0 2px rgba(59, 130, 246, 0.2);
}

/* === Buttons === */
button,
.btn {
  background-color: var(--color-primary);
  color: white;
  padding: 0.7rem 1.2rem;
  font-size: 1rem;
  border: none;
  border-radius: 6px;
  cursor: pointer;
  transition: background-color 0.2s ease;
}

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

/* === Utility Classes === */
.text-center {
  text-align: center;
}
.text-muted {
  color: var(--color-muted);
}
.container {
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 1rem;
}
.mt-1 { margin-top: 0.25rem; }
.mt-2 { margin-top: 0.5rem; }
.mt-4 { margin-top: 1rem; }
.mb-4 { margin-bottom: 1rem; }

/* === Layout Helpers === */
.full-height {
  min-height: 100vh;
  display: flex;
  flex-direction: column;
}

.flex-center {
  display: flex;
  justify-content: center;
  align-items: center;
}