* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

body {
    font-family: "Gilroy", sans-serif;
    color: var(--color-black);
    background-color: var(--color-gray-light);
}

.flex-center {
    display: flex;
    align-items: center;
    justify-content: center;
}

.abs-center {
    position: absolute;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
}

/* For spinners that are centred with a translate the animation must keep it. */
@keyframes spin {
    0% {
        transform: translate(-50%, -50%) rotate(0deg);
    }
    100% {
        transform: translate(-50%, -50%) rotate(360deg);
    }
}

@keyframes spin-in-place {
    0% {
        transform: rotate(0deg);
    }
    100% {
        transform: rotate(360deg);
    }
}

/* The start-up overlay lives in css/components/boot-loader.css. */

header {
    padding: 20px;
    background-color: var(--color-white);
    border-bottom: 1px solid var(--color-gray);
}

header > div {
    font-size: 18px;
    font-weight: 600;
}

nav {
    display: flex;
    gap: 10px;
    padding: 20px;
    background-color: var(--color-white);
    border-bottom: 1px solid var(--color-gray);
    box-shadow: var(--shadow-soft);
}

nav label {
    padding: 10px 20px;
    border-radius: var(--radius-lg);
    border: 1px solid var(--color-gray);
    cursor: pointer;
    background-color: var(--color-white);
    color: var(--color-gray-dark);
    transition: all 0.3s ease;
}

nav label:hover {
    background-color: var(--color-gray-light);
}

.main-container {
    background-image: url(../assets/bg.png);
    background-size: cover;
    background-position: center;
    background-repeat: no-repeat;
}

.border-md {
    border: var(--border-md);
}

/* Tabs are pure CSS: the checked radio reveals its section and lights its label. */
input[type="radio"][name="option"] {
    display: none;
}

input[type="radio"][name="option"]#option-a:checked
    ~ main
    nav
    label[for="option-a"],
input[type="radio"][name="option"]#option-b:checked
    ~ main
    nav
    label[for="option-b"],
input[type="radio"][name="option"]#option-e:checked
    ~ main
    nav
    label[for="option-e"] {
    background-color: var(--color-accent);
    color: var(--color-white);
}

.option-section {
    display: none;
}

input[type="radio"][name="option"]#option-a:checked ~ main .option-a-section,
input[type="radio"][name="option"]#option-b:checked ~ main .option-b-section,
input[type="radio"][name="option"]#option-e:checked ~ main .option-e-section {
    display: block;
}

/* Icon sprite: kept out of layout but not display:none, so <use> still resolves. */
.icon-sprite {
    position: absolute;
    width: 0;
    height: 0;
    overflow: hidden;
}