:root {
  --bg-color: #f8fafc;
  --surface-color: #ffffff;
  --surface-border: #e2e8f0;
  --text-main: #0f172a;
  --text-muted: #64748b;
  --accent-color: #2563eb;
  --accent-hover: #1d4ed8;
  --danger: #dc2626;
  --success: #16a34a;
  --font-sans: "Inter", system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif;
}

* {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

body {
  background-color: var(--bg-color);
  color: var(--text-main);
  font-family: var(--font-sans);
  min-height: 100vh;
  display: flex;
  flex-direction: column;
  -webkit-font-smoothing: antialiased;
}

/* Navbar */
nav {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 1rem 2.5rem;
  border-bottom: 1px solid var(--surface-border);
  background: rgba(255, 255, 255, 0.9);
  backdrop-filter: blur(10px);
  position: sticky;
  top: 0;
  z-index: 100;
}

.nav-brand {
  display: flex;
  align-items: center;
  gap: 0.75rem;
  font-weight: 700;
  font-size: 1.05rem;
  letter-spacing: -0.01em;
  color: var(--text-main);
}

.nav-logo-placeholder {
  width: 32px;
  height: 32px;
  background: var(--accent-color);
  color: #fff;
  border-radius: 8px;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 0.8rem;
  font-weight: 600;
}

.nav-links {
  display: flex;
  gap: 1.5rem;
  align-items: center;
}

.nav-links a {
  color: var(--text-muted);
  text-decoration: none;
  font-size: 0.9rem;
  font-weight: 500;
  transition: color 0.2s;
}

.nav-links a:hover, .nav-links a.active {
  color: var(--text-main);
}

/* Buttons */
.btn {
  background-color: var(--text-main);
  color: #ffffff;
  padding: 0.6rem 1.2rem;
  border-radius: 8px;
  font-weight: 600;
  font-size: 0.9rem;
  border: none;
  cursor: pointer;
  transition: all 0.2s ease;
  text-decoration: none;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 0.5rem;
}

.btn:hover {
  opacity: 0.92;
  transform: translateY(-1px);
}

.btn-primary {
  background-color: var(--accent-color);
  color: #fff;
}

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

.btn-outline {
  background: transparent;
  border: 1px solid var(--surface-border);
  color: var(--text-main);
}

.btn-outline:hover {
  border-color: var(--text-muted);
  background: #f1f5f9;
}

.btn-danger {
  background-color: var(--danger);
  color: #fff;
}

/* Container */
.container {
  max-width: 1200px;
  margin: 0 auto;
  padding: 3rem 1.5rem;
  width: 100%;
  flex: 1;
}

/* Hero Section */
.hero {
  text-align: center;
  padding: 4rem 1rem 3rem 1rem;
}

.hero h1 {
  font-size: 3.2rem;
  font-weight: 800;
  letter-spacing: -0.03em;
  margin-bottom: 1rem;
  color: var(--text-main);
}

.hero p {
  color: var(--text-muted);
  font-size: 1.15rem;
  max-width: 600px;
  margin: 0 auto 2.5rem auto;
  line-height: 1.6;
}

/* Cards & Layout */
.card {
  background-color: var(--surface-color);
  border: 1px solid var(--surface-border);
  border-radius: 14px;
  padding: 2rem;
  box-shadow: 0 4px 6px -1px rgba(0, 0, 0, 0.02), 0 2px 4px -1px rgba(0, 0, 0, 0.01);
}

.grid-2 {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 2rem;
}

@media(max-width: 768px) {
  .grid-2 { grid-template-columns: 1fr; }
  .hero h1 { font-size: 2.3rem; }
}

/* Form Controls */
.form-group {
  margin-bottom: 1.25rem;
}

.form-label {
  display: block;
  font-size: 0.85rem;
  font-weight: 600;
  color: var(--text-main);
  margin-bottom: 0.5rem;
}

.form-input {
  width: 100%;
  background: #ffffff;
  border: 1px solid var(--surface-border);
  border-radius: 8px;
  padding: 0.75rem 1rem;
  color: var(--text-main);
  font-size: 0.95rem;
  outline: none;
  transition: border-color 0.2s, box-shadow 0.2s;
}

.form-input:focus {
  border-color: var(--accent-color);
  box-shadow: 0 0 0 3px rgba(37, 99, 235, 0.1);
}

/* Modal */
.modal-backdrop {
  position: fixed;
  top: 0; left: 0; width: 100%; height: 100%;
  background: rgba(15, 23, 42, 0.5);
  backdrop-filter: blur(4px);
  display: flex;
  align-items: center;
  justify-content: center;
  z-index: 1000;
}

.modal {
  background: var(--surface-color);
  border: 1px solid var(--surface-border);
  border-radius: 16px;
  width: 100%;
  max-width: 500px;
  padding: 2.5rem;
  box-shadow: 0 20px 25px -5px rgba(0, 0, 0, 0.1);
}

/* Utility */
.hidden { display: none !important; }
.text-center { text-align: center; }
.mt-2 { margin-top: 1rem; }
.mb-2 { margin-bottom: 1rem; }