/* === Root Design Tokens === */
:root {
  --color-bg: #ffffff;
  --color-text: #111827;
  --color-primary: #10b981;
  --color-primary-hover: #059669;
  --color-secondary: #0f766e;
  --color-muted: #6b7280;
  --color-border: #e5e7eb;
  --color-footer-bg: #f9fafb;

  --font-base: system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;

  --radius-sm: 6px;
  --radius-md: 10px;
  --radius-lg: 14px;

  --transition-fast: 0.2s ease-in-out;

  --spacing-xs: 0.25rem;
  --spacing-sm: 0.5rem;
  --spacing-md: 1rem;
  --spacing-lg: 2rem;
  --spacing-xl: 3rem;

  --shadow-sm: 0 1px 2px rgba(0, 0, 0, 0.05);
  --shadow-md: 0 4px 6px rgba(0, 0, 0, 0.1);
}

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

html, body {
  font-family: var(--font-base);
  font-size: 16px;
  color: var(--color-text);
  background-color: var(--color-bg);
  line-height: 1.6;
  scroll-behavior: smooth;
}

/* === Typography === */
h1, h2, h3 {
  font-weight: 600;
  margin-bottom: var(--spacing-sm);
  color: var(--color-text);
}

p {
  margin-bottom: var(--spacing-md);
  color: var(--color-muted);
}

a {
  color: var(--color-primary);
  text-decoration: none;
  transition: color var(--transition-fast);
}

a:hover {
  color: var(--color-primary-hover);
}

/* === Layout Utilities === */
.container {
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 var(--spacing-md);
}

main {
  padding: var(--spacing-lg) var(--spacing-md);
}

/* === Navbar === */
header {
  position: sticky;
  top: 0;
  z-index: 1000;
  background-color: #000;
  color: #fff;
  box-shadow: var(--shadow-md);
  border-bottom: 1px solid var(--color-border);
}

header nav {
  max-width: 960px;
  margin: 0 auto;
  padding: var(--spacing-lg) var(--spacing-md);
  display: flex;
  flex-direction: column;
  align-items: center;
  text-align: center;
  gap: var(--spacing-md);
}

/* Brand Text */
.nav-brand {
  font-size: 1.75rem;
  font-weight: 800;
  color: var(--color-primary);
}

.nav-subtitle {
  color: var(--color-muted);
  font-size: 1.1rem;
  font-weight: 400;
}

/* === Email Signup Form === */
form[role="search"] {
  width: 100%;
  max-width: 600px;
  display: flex;
  flex-direction: column;
  gap: var(--spacing-sm);
}

@media (min-width: 640px) {
  form[role="search"] {
    flex-direction: row;
    justify-content: center;
    align-items: center;
  }
}

.input-email {
  flex-grow: 1;
  padding: var(--spacing-sm) var(--spacing-md);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  font-size: 1rem;
  color: #000;
  background: #fff;
  transition: border var(--transition-fast), box-shadow var(--transition-fast);
}

.input-email::placeholder {
  color: var(--color-muted);
}

.input-email:focus {
  border-color: var(--color-primary);
  box-shadow: 0 0 0 3px rgba(16, 185, 129, 0.3);
  outline: none;
}

.button {
  background-color: var(--color-primary);
  color: #fff;
  padding: var(--spacing-sm) var(--spacing-lg);
  border: none;
  border-radius: var(--radius-md);
  font-size: 1rem;
  font-weight: 600;
  cursor: pointer;
  transition: background-color var(--transition-fast), transform 0.1s ease;
}

.button:hover {
  background-color: var(--color-primary-hover);
  transform: translateY(-1px);
}

.button:focus {
  outline: none;
  box-shadow: 0 0 0 3px rgba(16, 185, 129, 0.5);
}

/* === Footer === */
footer {
  background-color: var(--color-footer-bg);
  padding: var(--spacing-lg) var(--spacing-md);
  text-align: center;
  font-size: 0.9rem;
  color: var(--color-muted);
  border-top: 1px solid var(--color-border);
}

.footer-links a {
  margin: 0 var(--spacing-xs);
  color: var(--color-muted);
}

.footer-links a:hover {
  color: var(--color-primary);
}

/* === Tables === */
table {
  width: 100%;
  border-collapse: collapse;
  margin-top: var(--spacing-md);
  background: #fff;
  box-shadow: var(--shadow-sm);
}

th, td {
  padding: var(--spacing-sm);
  text-align: left;
  border-bottom: 1px solid var(--color-border);
}

th {
  background-color: #f3f4f6;
  font-weight: 600;
}

/* === Forms (Generic) === */
input, select, textarea {
  font-family: var(--font-base);
  font-size: 1rem;
  padding: var(--spacing-sm) var(--spacing-md);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-sm);
  margin-bottom: var(--spacing-sm);
  color: var(--color-text);
}

input:focus, select:focus, textarea:focus {
  border-color: var(--color-primary);
  box-shadow: 0 0 0 3px rgba(16, 185, 129, 0.3);
  outline: none;
}

label {
  display: block;
  margin-bottom: 0.25rem;
  font-weight: 600;
  color: var(--color-text);
}

/* === Responsive === */
@media (max-width: 768px) {
  form[role="search"] {
    flex-direction: column;
    align-items: stretch;
  }

  .input-email, .button {
    width: 100%;
  }

  header nav {
    padding: var(--spacing-md);
  }
}