Use fluid scale custom properties and make everything mobile friendly

web-app/src/app.css

@@ -12,6 +12,40 @@
   --border-primary: 0.0625rem solid var(--bg-tertiary);
   --border-radius: 0.125rem;
 
+  /* Step -1: 14.9953px → 14.9953px */
+  --font-size--1: clamp(0.9372rem, 0.9372rem + 0cqi, 0.9372rem);
+  /* Step 0: 16px → 16px */
+  --font-size-0: clamp(1rem, 1rem + 0cqi, 1rem);
+  /* Step 1: 17.072px → 17.072px */
+  --font-size-1: clamp(1.067rem, 1.067rem + 0cqi, 1.067rem);
+  /* Step 2: 18.2158px → 18.2158px */
+  --font-size-2: clamp(1.1385rem, 1.1385rem + 0cqi, 1.1385rem);
+  /* Step 3: 19.4363px → 19.4363px */
+  --font-size-3: clamp(1.2148rem, 1.2148rem + 0cqi, 1.2148rem);
+  /* Step 4: 20.7385px → 20.7385px */
+  --font-size-4: clamp(1.2962rem, 1.2962rem + 0cqi, 1.2962rem);
+  /* Step 5: 22.128px → 22.128px */
+  --font-size-5: clamp(1.383rem, 1.383rem + 0cqi, 1.383rem);
+
+  /* Space 3xs: 4px → 5px */
+  --space-3xs: clamp(0.25rem, 0.2336rem + 0.0822cqi, 0.3125rem);
+  /* Space 2xs: 8px → 10px */
+  --space-2xs: clamp(0.5rem, 0.4671rem + 0.1645cqi, 0.625rem);
+  /* Space xs: 12px → 15px */
+  --space-xs: clamp(0.75rem, 0.7007rem + 0.2467cqi, 0.9375rem);
+  /* Space s: 16px → 20px */
+  --space-s: clamp(1rem, 0.9342rem + 0.3289cqi, 1.25rem);
+  /* Space m: 24px → 30px */
+  --space-m: clamp(1.5rem, 1.4013rem + 0.4934cqi, 1.875rem);
+  /* Space l: 32px → 40px */
+  --space-l: clamp(2rem, 1.8684rem + 0.6579cqi, 2.5rem);
+  /* Space xl: 48px → 60px */
+  --space-xl: clamp(3rem, 2.8026rem + 0.9868cqi, 3.75rem);
+  /* Space 2xl: 64px → 80px */
+  --space-2xl: clamp(4rem, 3.7368rem + 1.3158cqi, 5rem);
+  /* Space 3xl: 96px → 120px */
+  --space-3xl: clamp(6rem, 5.6053rem + 1.9737cqi, 7.5rem);
+
   color-scheme: light;
 }
 
@@ -51,11 +85,11 @@ body {
 section {
   display: flex;
   flex-direction: column;
-  gap: 1rem;
+  gap: var(--space-s);
 }
 
 section + section {
-  margin-block-start: 2rem;
+  margin-block-start: var(--space-l);
 }
 
 button,
@@ -63,7 +97,8 @@ label,
 select,
 summary,
 [role="button"],
-[role="option"] {
+[role="option"],
+label[for="toggle-mobile-preview"] {
   cursor: pointer;
 }
 
@@ -71,13 +106,14 @@ input,
 button,
 textarea,
 select,
-a[role="button"] {
+a[role="button"],
+label[for="toggle-mobile-preview"] {
   font: inherit;
   color: inherit;
   border: var(--border-primary);
   border-radius: var(--border-radius);
-  padding-inline: 0.5rem;
-  padding-block: 0.25rem;
+  padding-inline: var(--space-2xs);
+  padding-block: var(--space-3xs);
 }
 
 input,
@@ -90,6 +126,10 @@ textarea {
   resize: vertical;
 }
 
+input[type="file"] {
+  inline-size: 100%;
+}
+
 a {
   color: var(--color-accent);
 }
@@ -101,14 +141,21 @@ a[role="button"] {
 }
 
 button,
-a[role="button"] {
+a[role="button"],
+label[for="toggle-mobile-preview"] {
   background-color: var(--bg-secondary);
 }
 
-:is(button, a[role="button"]):hover {
+:is(button, a[role="button"], label[for="toggle-mobile-preview"]):hover {
   background-color: var(--bg-tertiary);
 }
 
+:is(a, button, input, textarea, select):focus,
+#toggle-mobile-preview:checked + label {
+  outline: 0.125rem solid var(--color-accent);
+  outline-offset: 0.25rem;
+}
+
 img,
 picture,
 svg,
@@ -132,18 +179,29 @@ h6 {
   overflow-wrap: break-word;
 }
 
-h1,
-h2,
-h3,
+h6 {
+  font-size: var(--font-size-0);
+}
+h5 {
+  font-size: var(--font-size-1);
+}
 h4 {
-  line-height: 1.2;
-  text-wrap: balance;
+  font-size: var(--font-size-2);
+}
+h3 {
+  font-size: var(--font-size-3);
+}
+h2 {
+  font-size: var(--font-size-4);
+}
+h1 {
+  font-size: var(--font-size-5);
 }
 
 form[method="POST"] {
   display: flex;
   flex-direction: column;
-  gap: 1rem;
+  gap: var(--space-s);
 }
 
 form > button[type="submit"] {
@@ -152,7 +210,7 @@ form > button[type="submit"] {
 
 form[method="GET"] {
   display: grid;
-  gap: 1rem;
+  gap: var(--space-s);
   grid-template-columns: repeat(auto-fit, minmax(min(100%, 20ch), 1fr));
   align-items: start;
 }
@@ -164,7 +222,7 @@ form[method="GET"] > button[type="submit"] {
 form label {
   display: flex;
   flex-direction: column;
-  gap: 0.25rem;
+  gap: var(--space-2xs);
   max-inline-size: 30ch;
 }
 
@@ -175,6 +233,6 @@ form label:has(textarea) {
 form .file-field {
   display: flex;
   align-items: end;
-  gap: 0.5rem;
+  gap: var(--space-2xs);
   flex-wrap: wrap;
 }