/* =====================================================
   TranslateXYZ — Button System
   Variants: primary · secondary · outline · ghost · amber
   Sizes:    sm · (base) · lg
   Modifier: .btn-block, .btn-icon-only, dark-surface adjustments
   ===================================================== */

.btn {
    font-family: inherit;
    font-weight: var(--fw-semibold);
    font-size: var(--fs-sm);
    line-height: 1;
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: 8px;
    padding: 12px 20px;
    border-radius: var(--r-pill);
    border: 1px solid transparent;
    cursor: pointer;
    transition: background var(--t-fast), color var(--t-fast),
                border-color var(--t-fast), transform var(--t-fast),
                box-shadow var(--t-fast);
    white-space: nowrap;
    text-decoration: none;
    user-select: none;
    -webkit-tap-highlight-color: transparent;
}
.btn:focus-visible { outline: none; box-shadow: var(--sh-focus); }
.btn .ico { width: 16px; height: 16px; flex-shrink: 0; }
.btn:disabled, .btn.is-disabled { cursor: not-allowed; }

/* ---------- PRIMARY ---------- */
.btn-primary {
    background: var(--green-500);
    color: #fff;
    box-shadow: 0 1px 2px rgba(0,0,0,.08), inset 0 1px 0 rgba(255,255,255,.18);
}
.btn-primary:hover {
    background: var(--green-600);
    color: #fff;
    transform: translateY(-1px);
    box-shadow: 0 4px 12px rgba(48,178,48,.32);
}
.btn-primary:active {
    background: var(--green-700);
    transform: translateY(0);
}
.btn-primary:disabled, .btn-primary.is-disabled {
    background: var(--green-200);
    color: var(--green-700);
    box-shadow: none;
}

/* ---------- SECONDARY (dark fill) ---------- */
.btn-secondary {
    background: var(--neutral-900);
    color: #fff;
}
.btn-secondary:hover {
    background: var(--neutral-700);
    color: #fff;
}

/* ---------- OUTLINE ---------- */
.btn-outline {
    background: transparent;
    color: var(--text-on-light-strong);
    border-color: var(--border-light-strong);
}
.btn-outline:hover {
    border-color: var(--green-500);
    color: var(--green-700);
    background: var(--green-50);
}

/* ---------- GHOST ---------- */
.btn-ghost {
    background: transparent;
    color: var(--text-on-light);
}
.btn-ghost:hover {
    background: var(--neutral-100);
    color: var(--text-on-light-strong);
}

/* ---------- AMBER (offer chips / highlights) ---------- */
.btn-amber {
    background: var(--amber-500);
    color: var(--neutral-900);
}
.btn-amber:hover {
    background: var(--amber-300);
    color: var(--neutral-900);
}

/* ---------- LINK STYLE ---------- */
.btn-link {
    background: transparent;
    color: var(--color-link);
    padding: 8px 4px;
    border-radius: var(--r-sm);
}
.btn-link:hover {
    color: var(--color-link-hover);
    background: transparent;
    text-decoration: underline;
    text-underline-offset: 4px;
}

/* ---------- DARK SURFACES ---------- */
.section-dark .btn-outline,
.demo-block.dark .btn-outline {
    color: var(--text-on-dark);
    border-color: var(--border-dark-strong);
}
.section-dark .btn-outline:hover,
.demo-block.dark .btn-outline:hover {
    background: rgba(255,255,255,.06);
    color: #fff;
    border-color: var(--green-300);
}
.section-dark .btn-ghost,
.demo-block.dark .btn-ghost {
    color: #fff;
}
.section-dark .btn-ghost:hover,
.demo-block.dark .btn-ghost:hover {
    background: rgba(255,255,255,.08);
    color: #fff;
}
.section-dark .btn-link,
.demo-block.dark .btn-link {
    color: var(--green-300);
}
.section-dark .btn-link:hover,
.demo-block.dark .btn-link:hover {
    color: #fff;
}

/* ---------- SIZES ---------- */
.btn-sm { padding: 8px 14px; font-size: var(--fs-xs); }
.btn-sm .ico { width: 14px; height: 14px; }
.btn-lg { padding: 16px 26px; font-size: var(--fs-md); }
.btn-lg .ico { width: 18px; height: 18px; }
.btn-xl { padding: 20px 32px; font-size: var(--fs-lg); border-radius: var(--r-pill); }

/* ---------- MODIFIERS ---------- */
.btn-block { display: flex; width: 100%; }
.btn-icon-only { padding: 12px; aspect-ratio: 1; }
.btn-icon-only.btn-sm { padding: 8px; }
.btn-icon-only.btn-lg { padding: 16px; }

/* ---------- BUTTON GROUP ---------- */
.btn-group { display: inline-flex; gap: var(--sp-2); flex-wrap: wrap; }
.btn-group-stretch { display: flex; gap: var(--sp-3); }
.btn-group-stretch > .btn { flex: 1; }