How to Style HTML Forms Using CSS

Browser-default forms look dated and inconsistent: each browser draws inputs, selects and checkboxes a little differently. With modern CSS you can make every control look polished and on-brand — while keeping it accessible.

We'll build a small design system for forms, one layer at a time.

1. Set up design tokens

Store colours and sizes in custom properties so the whole form can be re-themed in one place:

:root {
  --fc-accent: #645cec;
  --fc-accent-dark: #4f46e5;
  --fc-text: #0f172a;
  --fc-muted: #64748b;
  --fc-border: #d4d4e0;
  --fc-bg: #ffffff;
  --fc-field-bg: #ffffff;
  --fc-error: #dc2626;
  --fc-radius: 10px;
}

2. Normalise the basics

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

input, select, textarea, button {
  font: inherit;          /* controls don't inherit fonts by default */
  color: inherit;
}

.field { display: grid; gap: 6px; margin-bottom: 18px; }
.field label { font-weight: 600; font-size: 14px; color: var(--fc-text); }

font: inherit fixes the most common "why does my input look different?" problem — form controls use the system font unless told otherwise.

3. Style text inputs, selects and textareas together

.field :is(input, select, textarea) {
  width: 100%;
  padding: 12px 14px;
  font-size: 16px;
  background: var(--fc-field-bg);
  border: 1px solid var(--fc-border);
  border-radius: var(--fc-radius);
  transition: border-color .15s, box-shadow .15s;
}

.field textarea { min-height: 120px; resize: vertical; }

.field :is(input, select, textarea)::placeholder { color: #94a3b8; }

.field :is(input, select, textarea):hover { border-color: #b4b4c8; }

4. Clear, accessible focus states

Never remove focus outlines without a replacement — keyboard users depend on them. :focus-visible shows the ring for keyboard users without flashing it on every mouse click for buttons.

.field :is(input, select, textarea):focus {
  outline: none;
  border-color: var(--fc-accent);
  box-shadow: 0 0 0 4px color-mix(in srgb, var(--fc-accent) 20%, transparent);
}

button:focus-visible {
  outline: 3px solid var(--fc-accent);
  outline-offset: 3px;
}

5. Custom checkboxes and radios with accent-color

The quickest way to brand checkboxes, radios, range sliders and progress bars is one line:

form { accent-color: var(--fc-accent); }

Want full control? Use appearance: none and draw your own — the input remains a real, accessible checkbox:

input[type="checkbox"] {
  appearance: none;
  width: 20px;
  height: 20px;
  margin: 0;
  display: inline-grid;
  place-content: center;
  border: 1.5px solid var(--fc-border);
  border-radius: 6px;
  background: #fff;
  cursor: pointer;
}
input[type="checkbox"]::after {
  content: "";
  width: 10px;
  height: 10px;
  transform: scale(0);
  transition: transform .12s ease-in-out;
  clip-path: polygon(14% 44%, 0 65%, 50% 100%, 100% 16%, 80% 0%, 43% 62%);
  background: #fff;
}
input[type="checkbox"]:checked {
  background: var(--fc-accent);
  border-color: var(--fc-accent);
}
input[type="checkbox"]:checked::after { transform: scale(1); }
input[type="checkbox"]:focus-visible {
  outline: 3px solid color-mix(in srgb, var(--fc-accent) 40%, transparent);
  outline-offset: 2px;
}

6. A custom select arrow

.field select {
  appearance: none;
  padding-right: 40px;
  background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='12' height='8' fill='none' stroke='%2364748b' stroke-width='2'%3E%3Cpath d='M1 1l5 5 5-5'/%3E%3C/svg%3E");
  background-repeat: no-repeat;
  background-position: right 14px center;
  cursor: pointer;
}

7. Buttons with real states

.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  width: 100%;
  min-height: 50px;
  padding: 0 22px;
  font-weight: 700;
  color: #fff;
  background: var(--fc-accent);
  border: 0;
  border-radius: var(--fc-radius);
  cursor: pointer;
  transition: background .15s, transform .1s;
}
.btn:hover { background: var(--fc-accent-dark); }
.btn:active { transform: translateY(1px); }
.btn:disabled { opacity: .55; cursor: not-allowed; }

8. Validation styles that don't nag

:invalid matches empty required fields as soon as the page loads, which paints the whole form red before anyone has typed. :user-invalid waits until the user has interacted with the field:

.field :user-invalid {
  border-color: var(--fc-error);
}
.field :user-invalid:focus {
  box-shadow: 0 0 0 4px color-mix(in srgb, var(--fc-error) 18%, transparent);
}
.field .error { display: none; font-size: 13px; color: var(--fc-error); }
.field :user-invalid ~ .error { display: block; }

Don't rely on colour alone — pair red borders with a text message so colour-blind users get the information too.

9. Floating labels (done accessibly)

Floating labels save space and still keep a real label. The trick is :placeholder-shown with a single-space placeholder:

<div class="float">
  <input id="femail" name="email" type="email" placeholder=" " required>
  <label for="femail">Email address</label>
</div>

.float { position: relative; }
.float input { padding: 22px 14px 8px; }
.float label {
  position: absolute;
  left: 15px;
  top: 16px;
  color: var(--fc-muted);
  pointer-events: none;
  transition: transform .15s, font-size .15s, color .15s;
  transform-origin: left top;
}
.float input:focus + label,
.float input:not(:placeholder-shown) + label {
  transform: translateY(-9px);
  font-size: 12px;
  color: var(--fc-accent);
}

10. Dark mode in a few lines

Because everything uses tokens, dark mode is just new values:

@media (prefers-color-scheme: dark) {
  :root {
    --fc-text: #f1f5f9;
    --fc-muted: #94a3b8;
    --fc-border: #334155;
    --fc-bg: #0f172a;
    --fc-field-bg: #1e293b;
  }
  form { color-scheme: dark; }  /* dark native pickers and scrollbars */
}

11. Layout: keep it scannable

• One column is fastest to complete. Pair fields only when they belong together (first/last name, city/postcode).
• Labels above fields work on every screen size.
• Match field width to expected input — a postcode box doesn't need to be as wide as an address.
• Generous spacing between fields (16–24px) helps people see where one ends and the next begins.

Responsive layout is covered in depth in How to Create a Responsive HTML Form.

Accessibility checklist for styled forms

• Text and borders meet contrast guidelines (4.5:1 for text, 3:1 for input borders).
• Focus is always visible.
• Custom controls are still real <input> elements.
• Errors use text as well as colour.
• Tap targets are at least 44px tall.

Every one of our free HTML form templates uses these techniques, and they all post straight to Formclick — so they look good and deliver submissions to your inbox.