/*
 * Buttons. Every button in the app is a .btn; modifiers adjust the one base style.
 */

.btn {
    position: relative;
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: var(--space-2);
    min-height: var(--control-height);
    padding: 0 var(--space-4);
    border: var(--border);
    border-radius: var(--radius-small);
    background: var(--color-bg);
    color: var(--color-fg);
    font-size: var(--text-sm);
    font-weight: var(--font-weight-medium);
    line-height: 1;
    text-decoration: none;
    white-space: nowrap;
    cursor: pointer;
    transition: background var(--transition), color var(--transition), border-color var(--transition);
}

.btn:hover,
.btn[aria-expanded="true"] {
    background: var(--color-fg);
    color: var(--color-bg);
}

.btn:disabled,
.btn[aria-disabled="true"] {
    opacity: 0.4;
    pointer-events: none;
}

/* Filled: the main action in any group. */
.btn--primary {
    background: var(--color-fg);
    color: var(--color-bg);
}

.btn--primary:hover {
    background: var(--color-bg);
    color: var(--color-fg);
}

/* No outline until hovered: for quiet, secondary actions. */
.btn--ghost {
    border-color: transparent;
    background: transparent;
}

/* Looks like a link, behaves like a button. */
.btn--link {
    min-height: 0;
    padding: 0;
    border: 0;
    border-radius: 0;
    background: none;
    text-decoration: underline;
    text-decoration-thickness: var(--border-width);
    text-underline-offset: 0.2em;
}

.btn--link:hover {
    background: none;
    color: var(--color-muted);
}

/* No box at all: just the icon or text. For quiet navigation controls. */
.btn--bare {
    min-height: 0;
    padding: 0;
    border: 0;
    border-radius: var(--radius-small);
    background: none;
    font-size: var(--text-md);
}

.btn--bare:hover,
.btn--bare[aria-expanded="true"] {
    background: none;
    color: var(--color-muted);
}

.btn--icon {
    flex: none;
    width: var(--control-height);
    padding: 0;
    font-size: var(--text-md);
}

.btn--small {
    min-height: var(--control-height-small);
    padding: 0 var(--space-3);
    font-size: var(--text-xs);
}

.btn--small.btn--icon {
    width: var(--control-height-small);
    padding: 0;
    font-size: var(--text-sm);
}

/* No box at all: just the icon or text. For quiet navigation controls. */
.btn--bare {
    min-height: 0;
    padding: 0;
    border: 0;
    border-radius: var(--radius-small);
    background: none;
    font-size: var(--text-md);
}

.btn--bare:hover,
.btn--bare[aria-expanded="true"] {
    background: none;
    color: var(--color-muted);
}

.btn--large {
    min-height: 3.25rem;
    padding: 0 var(--space-6);
    font-size: var(--text-md);
}

.btn--block {
    width: 100%;
}

.btn--round {
    border-radius: var(--radius-round);
}

.btn-row {
    display: flex;
    flex-wrap: wrap;
    align-items: center;
    gap: var(--space-2);
}

/* Draws the eye to a button when something has arrived behind it. */
.btn.is-bouncing {
    animation: btn-bounce 700ms ease-out;
}

@keyframes btn-bounce {
    0%,
    100% {
        transform: translateY(0);
    }

    20% {
        transform: translateY(-0.5rem);
    }

    40% {
        transform: translateY(0);
    }

    60% {
        transform: translateY(-0.25rem);
    }

    80% {
        transform: translateY(0);
    }
}