diff --git a/calendar.css b/calendar.css
index 354c4e8..9597771 100644
--- a/calendar.css
+++ b/calendar.css
@@ -1,328 +1,6 @@
-/* Color tokens */
-:root {
-  --bg: #f6f7fb;
-  --panel: #fff;
-  --today: #f83;
-  --ink: #111;
-  --ink-rgb: 17, 17, 17;
-  --muted: #888;
-  --weekend: #888;
-  --firstday: #000;
-  --select: #aaf;
-  --label-bg: #fafbfe;
-  --label-bg-rgb: 250, 251, 254;
-
-  /* Layout */
-  --row-h: 2.2em;
-  --label-w: minmax(4em, 8%);
-  --cell-w: 1fr;
-  --cell-h: clamp(4em, 8vh, 8em);
-  --overlay-w: minmax(3rem, 5%);
-}
-
-/* Prevent text selection in calendar */
-#calendar-viewport, #calendar-content, .week-row, .cell,
-.calendar-header, .week-label, .month-name-label,
-.calendar-container, .jogwheel-viewport, .jogwheel-content {
-  -webkit-user-select: none;
-  -moz-user-select: none;
-  -ms-user-select: none;
-  user-select: none;
-  -webkit-touch-callout: none;
-  -webkit-tap-highlight-color: transparent;
-}
-
-/* Month tints (light) */
-.dec { background: hsl(220 20% 95%) }
-.jan { background: hsl(220 20% 88%) }
-.feb { background: hsl(220 20% 95%) }
-.mar { background: hsl(125 60% 88%) }
-.apr { background: hsl(125 60% 95%) }
-.may { background: hsl(125 60% 88%) }
-.jun { background: hsl(45 85% 95%) }
-.jul { background: hsl(45 85% 88%) }
-.aug { background: hsl(45 85% 95%) }
-.sep { background: hsl(18 78% 88%) }
-.oct { background: hsl(18 78% 95%) }
-.nov { background: hsl(18 78% 88%) }
-
-/* Color tokens (dark) */
-@media (prefers-color-scheme: dark) {
-  :root {
-    --bg: radial-gradient(1200px 800px at 20% -10%, #1c2130 0%, #0c0f16 35%, #0a0b11 100%);
-    --panel: #111318;
-    --today: #f83;
-    --ink: #ddd;
-    --ink-rgb: 221, 221, 221;
-    --muted: #888;
-    --weekend: #999;
-    --firstday: #fff;
-    --select: #44f;
-    --label-bg: #1a1d25;
-    --label-bg-rgb: 26, 29, 37;
-  }
-
-  /* Month tints (dark) */
-  .dec { background: hsl(220 20% 22%) }
-  .jan { background: hsl(220 20% 16%) }
-  .feb { background: hsl(220 20% 22%) }
-  .mar { background: hsl(125 40% 18%) }
-  .apr { background: hsl(125 40% 26%) }
-  .may { background: hsl(125 40% 18%) }
-  .jun { background: hsl(45 70% 24%) }
-  .jul { background: hsl(45 70% 18%) }
-  .aug { background: hsl(45 70% 24%) }
-  .sep { background: hsl(18 70% 18%) }
-  .oct { background: hsl(18 70% 26%) }
-  .nov { background: hsl(18 70% 18%) }
-}
-
-/* Layout & typography */
-* { box-sizing: border-box }
-
-body {
-  margin: 0;
-  font: 500 14px/1.2 ui-sans-serif, system-ui, -apple-system, Segoe UI, Roboto, Inter, Arial;
-  background: var(--bg);
-  color: var(--ink);
-}
-
-.wrap {
-  width: 100%;
-  margin: 0;
-  background: var(--panel);
-  height: 100vh;
-  display: flex;
-  flex-direction: column;
-  padding: 1rem;
-  white-space: pre-wrap;
-}
-
-header {
-  display: flex;
-  align-items: baseline;
-  justify-content: space-between;
-  margin-bottom: .75rem;
-  flex-shrink: 0;
-}
-
-.header-controls {
-  display: flex;
-  align-items: center;
-  gap: .75rem;
-}
-
-.today-date { cursor: pointer }
-.today-date::first-line { color: var(--today) }
-.today-button:hover { opacity: .8 }
-
-/* Header row */
-.calendar-header, #calendar-header {
-  display: grid;
-  grid-template-columns: var(--label-w) repeat(7, var(--cell-w)) var(--overlay-w);
-  border-bottom: .1em solid var(--muted);
-  align-items: last baseline;
-  flex-shrink: 0;
-  width: 100%;
-}
-.calendar-header .dow-label { display:grid; place-items:center; height: var(--cell-h); color: var(--muted) }
-.overlay-header-spacer { grid-column: -2 / -1 }
-
-/* Main container */
-.calendar-container, #calendar-container {
-  flex: 1;
-  overflow: hidden;
-  position: relative;
-  width: 100%;
-  display: flex;
-}
-
-/* Viewports (support id or class) */
-.calendar-viewport, #calendar-viewport {
-  height: 100%;
-  overflow-y: auto;
-  overflow-x: hidden;
-  flex: 1;
-  width: 100%;
-  scrollbar-width: none;
-}
-.calendar-viewport::-webkit-scrollbar,
-#calendar-viewport::-webkit-scrollbar { display: none }
-
-.jogwheel-viewport, #jogwheel-viewport {
-  position: absolute;
-  top: 0; right: 0; bottom: 0;
-  width: var(--overlay-w);
-  overflow-y: auto;
-  overflow-x: hidden;
-  scrollbar-width: none;
-  z-index: 20;
-  cursor: ns-resize;
-}
-.jogwheel-viewport::-webkit-scrollbar,
-#jogwheel-viewport::-webkit-scrollbar { display: none }
-
-.jogwheel-content, #jogwheel-content { position: relative; width: 100% }
-.calendar-content, #calendar-content { position: relative }
-
-/* Week row: label + 7-day grid + jogwheel column */
-.week-row {
-  display: grid;
-  grid-template-columns: var(--label-w) repeat(7, var(--cell-w)) var(--overlay-w);
-  position: relative;
-  overflow: visible;
-  height: var(--cell-h);
-  scroll-snap-align: start;
-  width: 100%;
-}
-
-/* Label cells */
-.dow-label, .week-label {
-  display: grid;
-  place-items: center;
-  width: 100%;
-  height: var(--cell-h);
-  color: var(--muted);
-  cursor: ns-resize;
-  font-size: 1.2em;
-}
-
-/* 7-day grid inside each week row */
-.week-row > .days-grid {
-  grid-column: 2 / span 7;
-  display: grid;
-  grid-template-columns: repeat(7, 1fr);
-  grid-auto-rows: 1fr;
-  position: relative;
-  height: 100%;
-  width: 100%;
-}
-
-/* Overlay sitting above the day cells, same 7-col grid */
-.week-row > .days-grid > .week-overlay {
-  margin-top: 1.2em;
-  position: absolute;
-  inset: 0;
-  pointer-events: none;
-  display: grid;
-  grid-template-columns: repeat(7, 1fr);
-  grid-auto-rows: 1fr;
-  z-index: 15;
-}
-
-/* Day cells */
-.dow { text-transform: uppercase }
-.cell {
-  position: relative;
-  display: flex;
-  flex-direction: column;
-  align-items: flex-start;
-  justify-content: flex-start;
-  padding: .25em;
-  overflow: hidden;
-  width: 100%;
-  height: var(--cell-h);
-  font-weight: 700;
-  cursor: pointer;
-  transition: background-color .15s ease;
-}
-.cell h1 {
-  top: .25em;
-  right: .25em;
-  padding: 0;
-  margin: 0;
-  transition: background-color .15s ease;
-  font-size: 1em;
-}
-.cell:hover h1 { text-shadow: 0 0 .2em }
-
-/* Fixed heights for cells and labels */
-.week-row .cell, .week-row .week-label { height: var(--cell-h) }
-
-/* Event (per-cell, if used) */
-.event {
-  font-size: .75em;
-  padding: .1em .3em;
-  margin: .1em 0;
-  border-radius: .2em;
-  color: white;
-  font-weight: 500;
-  white-space: nowrap;
-  overflow: hidden;
-  text-overflow: ellipsis;
-  width: 100%;
-  max-width: calc(100% - .5em);
-  line-height: 1.2;
-  cursor: pointer;
-  z-index: 5;
-}
-.event:hover { opacity: .8 }
-
-/* Spanning events in the overlay (grid-positioned, not absolutely measured) */
-.event-span {
-  font-size: .75em;
-  padding: 0 .5em;
-  border-radius: .4em;
-  color: white;
-  font-weight: 600;
-  white-space: nowrap;
-  overflow: hidden;
-  text-overflow: ellipsis;
-  line-height: 1.2;
-  height: 1.2em;
-  align-self: center;     /* vertically center within the overlay row */
-  justify-self: stretch;  /* stretch across chosen grid columns */
-  pointer-events: auto;   /* clickable despite overlay having none */
-  z-index: 1;
-}
-
-/* Selection styles */
-.weekend { color: var(--weekend) }
-.firstday { color: var(--firstday); text-shadow: 0 0 .1em rgba(var(--ink-rgb), .5) }
-
-input {
-  background: transparent;
-  border: none;
-  color: var(--ink);
-  width: 11em;
-}
-label:has(input[value]) { display: block }
-
-.selected {
-  background: var(--select);
-  border: 2px solid rgba(var(--ink-rgb), .3);
-  box-shadow: inset 0 0 0 1px rgba(255,255,255,.3);
-}
-.selected .event { opacity: .7 }
-
-.today h1 {
-  border-radius: 2em;
-  background: var(--today);
-  border: .2em solid var(--today);
-  margin: -.2em;
-}
-
-
-.month-name-label {
-  grid-column: -2 / -1;
-  font-size: 2em;
-  font-weight: 700;
-  color: var(--muted);
-  display: flex;
-  align-items: center;
-  justify-content: center;
-  pointer-events: none;
-  z-index: 15;
-  overflow: visible;
-  position: absolute;
-  top: 0; right: 0;
-  width: 100%;
-}
-.month-name-label > span {
-  display: inline-block;
-  white-space: nowrap;
-  writing-mode: vertical-rl;
-  text-orientation: mixed;
-  transform: rotate(180deg);
-  transform-origin: center;
-}
+/* Calendar CSS - Main file with imports */
+@import url('colors.css');
+@import url('layout.css');
+@import url('cells.css');
+@import url('events.css');
+@import url('utilities.css');
diff --git a/cells.css b/cells.css
new file mode 100644
index 0000000..c0960d9
--- /dev/null
+++ b/cells.css
@@ -0,0 +1,28 @@
+/* Day cells */
+.dow { text-transform: uppercase }
+.cell {
+  position: relative;
+  display: flex;
+  flex-direction: column;
+  align-items: flex-start;
+  justify-content: flex-start;
+  padding: .25em;
+  overflow: hidden;
+  width: 100%;
+  height: var(--cell-h);
+  font-weight: 700;
+  cursor: pointer;
+  transition: background-color .15s ease;
+}
+.cell h1 {
+  top: .25em;
+  right: .25em;
+  padding: 0;
+  margin: 0;
+  transition: background-color .15s ease;
+  font-size: 1em;
+}
+.cell:hover h1 { text-shadow: 0 0 .2em }
+
+/* Fixed heights for cells and labels */
+.week-row .cell, .week-row .week-label { height: var(--cell-h) }
diff --git a/colors.css b/colors.css
new file mode 100644
index 0000000..dcbb2c2
--- /dev/null
+++ b/colors.css
@@ -0,0 +1,77 @@
+/* Color tokens */
+:root {
+  --bg: #f6f7fb;
+  --panel: #fff;
+  --today: #f83;
+  --ink: #111;
+  --ink-rgb: 17, 17, 17;
+  --muted: #888;
+  --weekend: #888;
+  --firstday: #000;
+  --select: #aaf;
+  --label-bg: #fafbfe;
+  --label-bg-rgb: 250, 251, 254;
+}
+
+/* Month tints (light) */
+.dec { background: hsl(220 20% 95%) }
+.jan { background: hsl(220 20% 88%) }
+.feb { background: hsl(220 20% 95%) }
+.mar { background: hsl(125 60% 88%) }
+.apr { background: hsl(125 60% 95%) }
+.may { background: hsl(125 60% 88%) }
+.jun { background: hsl(45 85% 95%) }
+.jul { background: hsl(45 85% 88%) }
+.aug { background: hsl(45 85% 95%) }
+.sep { background: hsl(18 78% 88%) }
+.oct { background: hsl(18 78% 95%) }
+.nov { background: hsl(18 78% 88%) }
+
+/* Color tokens (dark) */
+@media (prefers-color-scheme: dark) {
+  :root {
+    --bg: radial-gradient(1200px 800px at 20% -10%, #1c2130 0%, #0c0f16 35%, #0a0b11 100%);
+    --panel: #111318;
+    --today: #f83;
+    --ink: #ddd;
+    --ink-rgb: 221, 221, 221;
+    --muted: #888;
+    --weekend: #999;
+    --firstday: #fff;
+    --select: #44f;
+    --label-bg: #1a1d25;
+    --label-bg-rgb: 26, 29, 37;
+  }
+
+  /* Month tints (dark) */
+  .dec { background: hsl(220 20% 22%) }
+  .jan { background: hsl(220 20% 16%) }
+  .feb { background: hsl(220 20% 22%) }
+  .mar { background: hsl(125 40% 18%) }
+  .apr { background: hsl(125 40% 26%) }
+  .may { background: hsl(125 40% 18%) }
+  .jun { background: hsl(45 70% 24%) }
+  .jul { background: hsl(45 70% 18%) }
+  .aug { background: hsl(45 70% 24%) }
+  .sep { background: hsl(18 70% 18%) }
+  .oct { background: hsl(18 70% 26%) }
+  .nov { background: hsl(18 70% 18%) }
+}
+
+/* Selection styles */
+.weekend { color: var(--weekend) }
+.firstday { color: var(--firstday); text-shadow: 0 0 .1em rgba(var(--ink-rgb), .5) }
+
+.selected {
+  background: var(--select);
+  border: 2px solid rgba(var(--ink-rgb), .3);
+  box-shadow: inset 0 0 0 1px rgba(255,255,255,.3);
+}
+.selected .event { opacity: .7 }
+
+.today h1 {
+  border-radius: 2em;
+  background: var(--today);
+  border: .2em solid var(--today);
+  margin: -.2em;
+}
diff --git a/events.css b/events.css
new file mode 100644
index 0000000..19cee94
--- /dev/null
+++ b/events.css
@@ -0,0 +1,36 @@
+/* Event (per-cell, if used) */
+.event {
+  font-size: .75em;
+  padding: .1em .3em;
+  margin: .1em 0;
+  border-radius: .2em;
+  color: white;
+  font-weight: 500;
+  white-space: nowrap;
+  overflow: hidden;
+  text-overflow: ellipsis;
+  width: 100%;
+  max-width: calc(100% - .5em);
+  line-height: 1.2;
+  cursor: pointer;
+  z-index: 5;
+}
+.event:hover { opacity: .8 }
+
+/* Spanning events in the overlay (grid-positioned, not absolutely measured) */
+.event-span {
+  font-size: .75em;
+  padding: 0 .5em;
+  border-radius: .4em;
+  color: white;
+  font-weight: 600;
+  white-space: nowrap;
+  overflow: hidden;
+  text-overflow: ellipsis;
+  line-height: 1.2;
+  height: 1.2em;
+  align-self: center;     /* vertically center within the overlay row */
+  justify-self: stretch;  /* stretch across chosen grid columns */
+  pointer-events: auto;   /* clickable despite overlay having none */
+  z-index: 1;
+}
diff --git a/layout.css b/layout.css
new file mode 100644
index 0000000..d3a1d01
--- /dev/null
+++ b/layout.css
@@ -0,0 +1,166 @@
+/* Layout variables */
+:root {
+  /* Layout */
+  --row-h: 2.2em;
+  --label-w: minmax(4em, 8%);
+  --cell-w: 1fr;
+  --cell-h: clamp(4em, 8vh, 8em);
+  --overlay-w: minmax(3rem, 5%);
+}
+
+/* Layout & typography */
+* { box-sizing: border-box }
+
+body {
+  margin: 0;
+  font: 500 14px/1.2 ui-sans-serif, system-ui, -apple-system, Segoe UI, Roboto, Inter, Arial;
+  background: var(--bg);
+  color: var(--ink);
+}
+
+.wrap {
+  width: 100%;
+  margin: 0;
+  background: var(--panel);
+  height: 100vh;
+  display: flex;
+  flex-direction: column;
+  padding: 1rem;
+  white-space: pre-wrap;
+}
+
+header {
+  display: flex;
+  align-items: baseline;
+  justify-content: space-between;
+  margin-bottom: .75rem;
+  flex-shrink: 0;
+}
+
+.header-controls {
+  display: flex;
+  align-items: center;
+  gap: .75rem;
+}
+
+.today-date { cursor: pointer }
+.today-date::first-line { color: var(--today) }
+.today-button:hover { opacity: .8 }
+
+/* Header row */
+.calendar-header, #calendar-header {
+  display: grid;
+  grid-template-columns: var(--label-w) repeat(7, var(--cell-w)) var(--overlay-w);
+  border-bottom: .1em solid var(--muted);
+  align-items: last baseline;
+  flex-shrink: 0;
+  width: 100%;
+}
+.calendar-header .dow-label { display:grid; place-items:center; height: var(--cell-h); color: var(--muted) }
+.overlay-header-spacer { grid-column: -2 / -1 }
+
+/* Main container */
+.calendar-container, #calendar-container {
+  flex: 1;
+  overflow: hidden;
+  position: relative;
+  width: 100%;
+  display: flex;
+}
+
+/* Viewports (support id or class) */
+.calendar-viewport, #calendar-viewport {
+  height: 100%;
+  overflow-y: auto;
+  overflow-x: hidden;
+  flex: 1;
+  width: 100%;
+  scrollbar-width: none;
+}
+.calendar-viewport::-webkit-scrollbar,
+#calendar-viewport::-webkit-scrollbar { display: none }
+
+.jogwheel-viewport, #jogwheel-viewport {
+  position: absolute;
+  top: 0; right: 0; bottom: 0;
+  width: var(--overlay-w);
+  overflow-y: auto;
+  overflow-x: hidden;
+  scrollbar-width: none;
+  z-index: 20;
+  cursor: ns-resize;
+}
+.jogwheel-viewport::-webkit-scrollbar,
+#jogwheel-viewport::-webkit-scrollbar { display: none }
+
+.jogwheel-content, #jogwheel-content { position: relative; width: 100% }
+.calendar-content, #calendar-content { position: relative }
+
+/* Week row: label + 7-day grid + jogwheel column */
+.week-row {
+  display: grid;
+  grid-template-columns: var(--label-w) repeat(7, var(--cell-w)) var(--overlay-w);
+  position: relative;
+  overflow: visible;
+  height: var(--cell-h);
+  scroll-snap-align: start;
+  width: 100%;
+}
+
+/* Label cells */
+.dow-label, .week-label {
+  display: grid;
+  place-items: center;
+  width: 100%;
+  height: var(--cell-h);
+  color: var(--muted);
+  cursor: ns-resize;
+  font-size: 1.2em;
+}
+
+/* 7-day grid inside each week row */
+.week-row > .days-grid {
+  grid-column: 2 / span 7;
+  display: grid;
+  grid-template-columns: repeat(7, 1fr);
+  grid-auto-rows: 1fr;
+  position: relative;
+  height: 100%;
+  width: 100%;
+}
+
+/* Overlay sitting above the day cells, same 7-col grid */
+.week-row > .days-grid > .week-overlay {
+  margin-top: 1.2em;
+  position: absolute;
+  inset: 0;
+  pointer-events: none;
+  display: grid;
+  grid-template-columns: repeat(7, 1fr);
+  grid-auto-rows: 1fr;
+  z-index: 15;
+}
+
+.month-name-label {
+  grid-column: -2 / -1;
+  font-size: 2em;
+  font-weight: 700;
+  color: var(--muted);
+  display: flex;
+  align-items: center;
+  justify-content: center;
+  pointer-events: none;
+  z-index: 15;
+  overflow: visible;
+  position: absolute;
+  top: 0; right: 0;
+  width: 100%;
+}
+.month-name-label > span {
+  display: inline-block;
+  white-space: nowrap;
+  writing-mode: vertical-rl;
+  text-orientation: mixed;
+  transform: rotate(180deg);
+  transform-origin: center;
+}
diff --git a/utilities.css b/utilities.css
new file mode 100644
index 0000000..fd88bdf
--- /dev/null
+++ b/utilities.css
@@ -0,0 +1,19 @@
+/* Prevent text selection in calendar */
+#calendar-viewport, #calendar-content, .week-row, .cell,
+.calendar-header, .week-label, .month-name-label,
+.calendar-container, .jogwheel-viewport, .jogwheel-content {
+  -webkit-user-select: none;
+  -moz-user-select: none;
+  -ms-user-select: none;
+  user-select: none;
+  -webkit-touch-callout: none;
+  -webkit-tap-highlight-color: transparent;
+}
+
+input {
+  background: transparent;
+  border: none;
+  color: var(--ink);
+  width: 11em;
+}
+label:has(input[value]) { display: block }