diff --git a/src/styles.css b/src/styles.css
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+@import "tailwindcss" source(none);
+@source "../src";
+@import "tw-animate-css";
+
+@custom-variant dark (&:is(.dark *));
+
+/*
+ * Design system definition.
+ *
+ * The @theme inline block maps CSS custom properties to Tailwind utility
+ * classes (e.g. --color-primary -> bg-primary, text-primary).
+ *
+ * The :root and .dark blocks define the actual color values using oklch.
+ * All colors MUST use oklch format.
+ *
+ * To add a new semantic color:
+ * 1. Add the variable to :root (light value) and .dark (dark value)
+ * 2. Register it in @theme inline as --color-<name>: var(--<name>)
+ */
+
+@theme inline {
+  --radius-sm: calc(var(--radius) - 4px);
+  --radius-md: calc(var(--radius) - 2px);
+  --radius-lg: var(--radius);
+  --radius-xl: calc(var(--radius) + 4px);
+  --radius-2xl: calc(var(--radius) + 8px);
+  --radius-3xl: calc(var(--radius) + 12px);
+  --radius-4xl: calc(var(--radius) + 16px);
+  --color-background: var(--background);
+  --color-foreground: var(--foreground);
+  --color-card: var(--card);
+  --color-card-foreground: var(--card-foreground);
+  --color-popover: var(--popover);
+  --color-popover-foreground: var(--popover-foreground);
+  --color-primary: var(--primary);
+  --color-primary-foreground: var(--primary-foreground);
+  --color-secondary: var(--secondary);
+  --color-secondary-foreground: var(--secondary-foreground);
+  --color-muted: var(--muted);
+  --color-muted-foreground: var(--muted-foreground);
+  --color-accent: var(--accent);
+  --color-accent-foreground: var(--accent-foreground);
+  --color-destructive: var(--destructive);
+  --color-destructive-foreground: var(--destructive-foreground);
+  --color-border: var(--border);
+  --color-input: var(--input);
+  --color-ring: var(--ring);
+  --color-ring-offset-background: var(--background);
+  --color-chart-1: var(--chart-1);
+  --color-chart-2: var(--chart-2);
+  --color-chart-3: var(--chart-3);
+  --color-chart-4: var(--chart-4);
+  --color-chart-5: var(--chart-5);
+  --color-sidebar: var(--sidebar);
+  --color-sidebar-foreground: var(--sidebar-foreground);
+  --color-sidebar-primary: var(--sidebar-primary);
+  --color-sidebar-primary-foreground: var(--sidebar-primary-foreground);
+  --color-sidebar-accent: var(--sidebar-accent);
+  --color-sidebar-accent-foreground: var(--sidebar-accent-foreground);
+  --color-sidebar-border: var(--sidebar-border);
+  --color-sidebar-ring: var(--sidebar-ring);
+}
+
+:root {
+  --radius: 0.625rem;
+  --background: oklch(1 0 0);
+  --foreground: oklch(0.129 0.042 264.695);
+  --card: oklch(1 0 0);
+  --card-foreground: oklch(0.129 0.042 264.695);
+  --popover: oklch(1 0 0);
+  --popover-foreground: oklch(0.129 0.042 264.695);
+  --primary: oklch(0.31 0.086 252.1); /* Bayside navy #06315a */
+  --primary-foreground: oklch(0.984 0.003 247.858);
+  --secondary: oklch(0.968 0.007 247.896);
+  --secondary-foreground: oklch(0.208 0.042 265.755);
+  --muted: oklch(0.968 0.007 247.896);
+  --muted-foreground: oklch(0.554 0.046 257.417);
+  --accent: oklch(0.968 0.007 247.896);
+  --accent-foreground: oklch(0.208 0.042 265.755);
+  --destructive: oklch(0.577 0.245 27.325);
+  --destructive-foreground: oklch(0.984 0.003 247.858);
+  --border: oklch(0.929 0.013 255.508);
+  --input: oklch(0.929 0.013 255.508);
+  --ring: oklch(0.515 0.109 249.1);
+  --chart-1: oklch(0.646 0.222 41.116);
+  --chart-2: oklch(0.6 0.118 184.704);
+  --chart-3: oklch(0.398 0.07 227.392);
+  --chart-4: oklch(0.828 0.189 84.429);
+  --chart-5: oklch(0.769 0.188 70.08);
+  --sidebar: oklch(0.984 0.003 247.858);
+  --sidebar-foreground: oklch(0.129 0.042 264.695);
+  --sidebar-primary: oklch(0.31 0.086 252.1); /* Bayside navy */
+  --sidebar-primary-foreground: oklch(0.984 0.003 247.858);
+  --sidebar-accent: oklch(0.968 0.007 247.896);
+  --sidebar-accent-foreground: oklch(0.208 0.042 265.755);
+  --sidebar-border: oklch(0.929 0.013 255.508);
+  --sidebar-ring: oklch(0.704 0.04 256.788);
+}
+
+.dark {
+  --background: oklch(0.129 0.042 264.695);
+  --foreground: oklch(0.984 0.003 247.858);
+  --card: oklch(0.208 0.042 265.755);
+  --card-foreground: oklch(0.984 0.003 247.858);
+  --popover: oklch(0.208 0.042 265.755);
+  --popover-foreground: oklch(0.984 0.003 247.858);
+  --primary: oklch(0.515 0.109 249.1); /* Bayside navy (lighter for dark bg) */
+  --primary-foreground: oklch(0.984 0.003 247.858);
+  --secondary: oklch(0.279 0.041 260.031);
+  --secondary-foreground: oklch(0.984 0.003 247.858);
+  --muted: oklch(0.279 0.041 260.031);
+  --muted-foreground: oklch(0.704 0.04 256.788);
+  --accent: oklch(0.279 0.041 260.031);
+  --accent-foreground: oklch(0.984 0.003 247.858);
+  --destructive: oklch(0.704 0.191 22.216);
+  --destructive-foreground: oklch(0.984 0.003 247.858);
+  --border: oklch(1 0 0 / 10%);
+  --input: oklch(1 0 0 / 15%);
+  --ring: oklch(0.551 0.027 264.364);
+  --chart-1: oklch(0.488 0.243 264.376);
+  --chart-2: oklch(0.696 0.17 162.48);
+  --chart-3: oklch(0.769 0.188 70.08);
+  --chart-4: oklch(0.627 0.265 303.9);
+  --chart-5: oklch(0.645 0.246 16.439);
+  --sidebar: oklch(0.208 0.042 265.755);
+  --sidebar-foreground: oklch(0.984 0.003 247.858);
+  --sidebar-primary: oklch(0.515 0.109 249.1); /* Bayside navy */
+  --sidebar-primary-foreground: oklch(0.984 0.003 247.858);
+  --sidebar-accent: oklch(0.279 0.041 260.031);
+  --sidebar-accent-foreground: oklch(0.984 0.003 247.858);
+  --sidebar-border: oklch(1 0 0 / 10%);
+  --sidebar-ring: oklch(0.551 0.027 264.364);
+}
+
+@layer base {
+  * {
+    border-color: var(--color-border);
+  }
+
+  body {
+    background-color: var(--color-background);
+    color: var(--color-foreground);
+  }
+}
+
+/* ── Print: report cards, progress reports, invoices ────────────────────────
+   Documents are ordinary pages on screen; @media print strips the app chrome
+   so what lands on paper (or in "Save as PDF") is just the document. Mark app
+   furniture with .no-print, and wrap each student's document in .print-page so
+   a batch of report cards breaks one-per-sheet. */
+@page {
+  margin: 14mm;
+}
+
+@media print {
+  .no-print {
+    display: none !important;
+  }
+
+  html,
+  body {
+    background: #fff !important;
+  }
+
+  /* The authenticated layout scrolls <main>; printing needs it to overflow. */
+  main {
+    overflow: visible !important;
+  }
+
+  .print-doc {
+    border: 0 !important;
+    box-shadow: none !important;
+    padding: 0 !important;
+    max-width: none !important;
+  }
+
+  .print-page + .print-page {
+    break-before: page;
+  }
+
+  tr,
+  td,
+  th {
+    break-inside: avoid;
+  }
+
+  a {
+    color: inherit;
+    text-decoration: none;
+  }
+}