:root {
  --color-primary: #e74c3c;
  --color-primary-hover: #c0392b;
  --color-bg: #f8f9fa;
  --color-card: #ffffff;
  --color-border: #e0e0e0;
  --color-text: #333333;
  --color-text-muted: #6c757d;
  --shadow: 0 2px 8px rgba(0, 0, 0, 0.08);
  --radius: 8px;
  --radius-lg: 12px;
}

* {
  box-sizing: border-box;
}

body {
  margin: 0;
  font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen, Ubuntu, sans-serif;
  background: var(--color-bg);
  color: var(--color-text);
  line-height: 1.5;
  min-height: 100vh;
}

/* Header */
.header {
  background: var(--color-card);
  box-shadow: var(--shadow);
  padding: 1rem 2rem;
  position: sticky;
  top: 0;
  z-index: 100;
}

.header-inner {
  max-width: 1200px;
  margin: 0 auto;
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.logo {
  font-size: 1.5rem;
  font-weight: 700;
  color: var(--color-primary);
  text-decoration: none;
}

.nav {
  display: flex;
  gap: 1.5rem;
}

.nav a {
  color: var(--color-text);
  text-decoration: none;
  font-weight: 500;
  padding: 0.5rem 0;
  border-bottom: 2px solid transparent;
  transition: all 0.2s;
}

.nav a:hover,
.nav a.active {
  color: var(--color-primary);
  border-bottom-color: var(--color-primary);
}

/* Main content */
.main {
  max-width: 1200px;
  margin: 0 auto;
  padding: 2rem;
}

/* Page title */
.page-title {
  font-size: 2rem;
  font-weight: 700;
  margin: 0 0 0.5rem;
  color: var(--color-text);
}

.page-subtitle {
  color: var(--color-text-muted);
  margin: 0 0 2rem;
  font-size: 1rem;
}

/* Buttons */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 0.5rem;
  padding: 0.75rem 1.5rem;
  font-size: 1rem;
  font-weight: 600;
  border: none;
  border-radius: var(--radius);
  cursor: pointer;
  transition: all 0.2s;
  text-decoration: none;
  font-family: inherit;
}

.btn-primary {
  background: var(--color-primary);
  color: white;
}

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

.btn-primary:disabled {
  opacity: 0.6;
  cursor: not-allowed;
  transform: none;
}

.btn-secondary {
  background: var(--color-border);
  color: var(--color-text);
}

.btn-secondary:hover {
  background: #d0d0d0;
}