Add password-protected access flow

public/styles.css

@@ -37,6 +37,47 @@ body {
   -webkit-font-smoothing: antialiased;
 }
 
+.hidden {
+  display: none !important;
+}
+
+.login-screen {
+  min-height: 100vh;
+  display: flex;
+  align-items: center;
+  justify-content: center;
+  padding: 24px;
+  background:
+    radial-gradient(circle at top, rgba(59, 130, 246, 0.18), transparent 32%),
+    linear-gradient(180deg, #0b1220 0%, #0f172a 100%);
+}
+
+.login-card {
+  width: 100%;
+  max-width: 420px;
+  background: rgba(15, 23, 42, 0.92);
+  border: 1px solid var(--border);
+  border-radius: 20px;
+  box-shadow: var(--shadow-md), 0 24px 60px rgba(0, 0, 0, 0.35);
+  padding: 32px;
+}
+
+.login-brand {
+  margin-bottom: 22px;
+}
+
+.login-brand p {
+  margin-top: 12px;
+  color: var(--text-secondary);
+  font-size: 14px;
+}
+
+.login-form {
+  display: flex;
+  flex-direction: column;
+  gap: 14px;
+}
+
 button,
 input,
 textarea,