:root {
--primary-color: #007bff;
--primary-hover: #0056b3;
--secondary-color: #6c757d;
--secondary-hover: #5a6268;
--background-color: #f8f9fa;
--card-background: #ffffff;
--text-color: #343a40;
--border-color: #dee2e6;
--error-color: #dc3545;
--focus-ring-color: rgba(0, 123, 255, 0.25);
--font-family: 'Inter', sans-serif;
}

body {
font-family: var(--font-family);
background-color: var(--background-color);
color: var(--text-color);
margin: 0;
display: flex;
justify-content: center;
align-items: center;
min-height: 100vh;
padding: 1rem;
}

.qr-container {
background-color: var(--card-background);
padding: 2rem;
border-radius: 12px;
box-shadow: 0 8px 30px rgba(0, 0, 0, 0.1);
width: 100%;
max-width: 500px;
}

header { text-align: center; margin-bottom: 1.5rem; }
header h1 { margin: 0 0 0.5rem 0; font-size: 2rem; font-weight: 700; }
header p { margin: 0; color: var(--secondary-color); }

#form-heading {
font-size: 1.25rem; font-weight: 700; margin-bottom: 1.5rem;
margin-top: 0; text-align: center;
}
#form-heading:focus { outline: none; }

.form-group { margin-bottom: 1.25rem; }
label { display: block; margin-bottom: 0.5rem; font-weight: 500; }

input, textarea, select {
width: 100%; padding: 0.75rem; border: 1px solid var(--border-color);
border-radius: 6px; font-size: 1rem; font-family: inherit;
transition: border-color 0.2s, box-shadow 0.2s; background-color: #fff;
}
input:focus, textarea:focus, select:focus {
outline: none; border-color: var(--primary-color);
box-shadow: 0 0 0 3px var(--focus-ring-color);
}
textarea { resize: vertical; min-height: 80px; }

.select-wrapper { position: relative; width: 100%; }
.select-arrow {
font-size: 0.8rem; position: absolute; right: 1rem; top: 50%;
transform: translateY(-50%); pointer-events: none; color: var(--secondary-color);
}
select { appearance: none; -webkit-appearance: none; padding-right: 2.5rem; }

.url-input-container { display: flex; gap: 0.5rem; align-items: center; }
.url-input-container .protocol-select { width: auto; flex-shrink: 0; }
.url-input-container #url-data { flex-grow: 1; }
.field-note { font-size: 0.875rem; color: var(--secondary-color); margin-top: 0.5rem; }

button {
display: inline-flex; align-items: center; justify-content: center; gap: 0.5rem;
font-family: inherit; font-weight: 500; font-size: 1rem; padding: 0.75rem 1.5rem;
border-radius: 6px; border: none; cursor: pointer;
transition: background-color 0.2s, box-shadow 0.2s, opacity 0.2s; width: 100%;
}
button:focus-visible { outline: none; box-shadow: 0 0 0 3px var(--focus-ring-color); }
button:disabled { background-color: #a0c9f7; cursor: not-allowed; opacity: 0.7; }

.button-primary { background-color: var(--primary-color); color: white; margin-top: 1.5rem; }
.button-primary:not(:disabled):hover { background-color: var(--primary-hover); }
.button-secondary { background-color: var(--secondary-color); color: white; }
.button-secondary:hover { background-color: var(--secondary-hover); }
.button-tertiary { background-color: transparent; color: var(--primary-color); border: 1px solid var(--primary-color); }
.button-tertiary:hover { background-color: rgba(0, 123, 255, 0.05); }

/* --- Customization Button & Panel --- */
.button-customize {
background-color: #f1f1f1; color: var(--text-color); margin-top: 1rem;
justify-content: space-between;
}
.button-customize:hover { background-color: #e6e6e6; }
.chevron-icon { transition: transform 0.3s ease; }
.button-customize[aria-expanded="true"] .chevron-icon { transform: rotate(180deg); }

#customization-panel {
    margin-top: 1rem;
    border-top: 1px solid var(--border-color);
}
.panel-content {
    padding-top: 1rem;
}
.color-picker-group { display: flex; gap: 1.5rem; }
.color-picker-group .form-group { flex: 1; margin-bottom: 0; }


/* --- Result & Error Styles --- */
#qr-result-container { text-align: center; }
#qrcode-wrapper {
display: flex; justify-content: center; align-items: center; margin: 2rem auto;
padding: 1rem; border: 1px solid var(--border-color); border-radius: 8px; width: fit-content;
}
#qrcode canvas, #qrcode img { border-radius: 4px; }
.button-group { display: flex; gap: 1rem; margin-top: 1.5rem; }

.error {
color: var(--error-color); background-color: rgba(220, 53, 69, 0.1);
border: 1px solid rgba(220, 53, 69, 0.2); border-radius: 6px;
padding: 0.75rem; margin-top: 1.5rem; display: none;
}

.hidden { display: none; }
.sr-only {
position: absolute; width: 1px; height: 1px; padding: 0; margin: -1px;
overflow: hidden; clip: rect(0, 0, 0, 0); white-space: nowrap; border: 0;
}
.sr-only:focus {
position: static; width: auto; height: auto; margin: 0;
overflow: visible; clip: auto; white-space: normal;
}

@media (max-width: 600px) {
body { padding: 0.5rem; }
.qr-container { padding: 1.5rem; }
header h1 { font-size: 1.75rem; }
.button-group { flex-direction: column; }
.color-picker-group { flex-direction: column; gap: 1rem; }
}