/* ──────────────────────────────────────────────────────────────
   CalcGPT — Auth Page Styles (Login / Signup)
   Inherits CSS variables from style.css :root
   ────────────────────────────────────────────────────────────── */

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

:root {
  --bg-primary: #0a0a0f;
  --bg-secondary: #12121a;
  --bg-tertiary: #1a1a28;
  --bg-elevated: #22223a;
  --bg-hover: #2a2a44;
  --glass-bg: rgba(20, 20, 35, 0.75);
  --glass-border: rgba(255, 255, 255, 0.06);
  --text-primary: #ececf1;
  --text-secondary: #a1a1b5;
  --text-muted: #6b6b80;
  --accent: #8b5cf6;
  --accent-glow: rgba(139, 92, 246, 0.25);
  --accent-gradient: linear-gradient(135deg, #8b5cf6, #6366f1, #3b82f6);
  --success: #4ade80;
  --error: #ef4444;
  --border: rgba(255, 255, 255, 0.06);
  --radius-md: 12px;
  --radius-lg: 16px;
  --transition-fast: 150ms cubic-bezier(0.4, 0, 0.2, 1);
  --transition-smooth: 300ms cubic-bezier(0.4, 0, 0.2, 1);
}

html { font-size: 16px; -webkit-font-smoothing: antialiased; }

body {
  font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
  background: var(--bg-primary);
  color: var(--text-primary);
  min-height: 100vh;
  display: flex;
  align-items: center;
  justify-content: center;
}

.auth-container {
  width: 100%;
  max-width: 420px;
  padding: 2rem;
}

.auth-logo {
  text-align: center;
  margin-bottom: 2rem;
}
.auth-logo h1 {
  font-size: 1.75rem;
  font-weight: 700;
  background: var(--accent-gradient);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}
.auth-logo p {
  color: var(--text-muted);
  font-size: 0.875rem;
  margin-top: 0.5rem;
}

.auth-card {
  background: var(--glass-bg);
  border: 1px solid var(--glass-border);
  border-radius: var(--radius-lg);
  padding: 2rem;
  backdrop-filter: blur(24px);
}

.auth-tabs {
  display: flex;
  gap: 0;
  margin-bottom: 1.5rem;
  background: var(--bg-secondary);
  border-radius: var(--radius-md);
  padding: 4px;
}
.auth-tab {
  flex: 1;
  padding: 0.625rem;
  text-align: center;
  font-size: 0.875rem;
  font-weight: 600;
  color: var(--text-muted);
  background: transparent;
  border: none;
  border-radius: 8px;
  cursor: pointer;
  transition: var(--transition-fast);
}
.auth-tab.active {
  background: var(--bg-elevated);
  color: var(--text-primary);
}

.auth-form { display: none; }
.auth-form.active { display: block; }

.form-group {
  margin-bottom: 1rem;
}
.form-group label {
  display: block;
  font-size: 0.8125rem;
  font-weight: 500;
  color: var(--text-secondary);
  margin-bottom: 0.375rem;
}
.form-group input {
  width: 100%;
  padding: 0.75rem 1rem;
  background: var(--bg-secondary);
  border: 1px solid var(--border);
  border-radius: var(--radius-md);
  color: var(--text-primary);
  font-size: 0.9375rem;
  outline: none;
  transition: var(--transition-fast);
}
.form-group input:focus {
  border-color: var(--accent);
  box-shadow: 0 0 0 3px var(--accent-glow);
}
.form-group input::placeholder {
  color: var(--text-muted);
}

.auth-btn {
  width: 100%;
  padding: 0.75rem;
  background: var(--accent-gradient);
  color: white;
  font-size: 0.9375rem;
  font-weight: 600;
  border: none;
  border-radius: var(--radius-md);
  cursor: pointer;
  transition: var(--transition-smooth);
  margin-top: 0.5rem;
}
.auth-btn:hover {
  opacity: 0.9;
  transform: translateY(-1px);
}
.auth-btn:disabled {
  opacity: 0.5;
  cursor: not-allowed;
  transform: none;
}

.auth-error {
  background: rgba(239, 68, 68, 0.1);
  border: 1px solid rgba(239, 68, 68, 0.3);
  color: var(--error);
  padding: 0.625rem 1rem;
  border-radius: var(--radius-md);
  font-size: 0.8125rem;
  margin-bottom: 1rem;
  display: none;
}
.auth-error.visible { display: block; }

.auth-success {
  background: rgba(74, 222, 128, 0.1);
  border: 1px solid rgba(74, 222, 128, 0.3);
  color: var(--success);
  padding: 0.625rem 1rem;
  border-radius: var(--radius-md);
  font-size: 0.8125rem;
  margin-bottom: 1rem;
  display: none;
}
.auth-success.visible { display: block; }

.auth-footer {
  text-align: center;
  margin-top: 1.5rem;
  font-size: 0.8125rem;
  color: var(--text-muted);
}
.auth-footer a {
  color: var(--accent);
  text-decoration: none;
}

.form-hint {
  font-size: 0.75rem;
  color: var(--text-muted);
  margin-top: 0.375rem;
}