/* ----------------------------------------------------------------
   Unified button system
   Usage: <a class="sp-btn sp-btn--primary">…</a>
   Compose: base + variant + optional size/modifier
   ---------------------------------------------------------------- */

.sp-btn {
    display: inline-flex;
    align-items: center;
    gap: 6px;
    padding: 10px 20px;
    font-family: var(--font-text);
    font-size: 14px;
    font-weight: 700;
    line-height: 1.6;
    text-transform: uppercase;
    letter-spacing: 0.02em;
    text-decoration: none;
    white-space: nowrap;
    border: 1px solid transparent;
    border-radius: var(--radius-lg);
    cursor: pointer;
    transition: background-color 0.15s, color 0.15s, border-color 0.15s;
}

.sp-btn svg {
    flex-shrink: 0;
}

/* Variant: primary — filled accent background */
.sp-btn--primary {
    background-color: var(--color-accent-1);
    border-color: var(--color-accent-1);
    color: var(--color-white);
}

.sp-btn--primary:hover {
    background-color: var(--color-accent-1-hover);
    border-color: var(--color-accent-1-hover);
    color: var(--color-white);
}

/* Variant: outline — accent-colored border, transparent fill */
.sp-btn--outline {
    background-color: transparent;
    border-color: var(--color-accent-1);
    color: var(--color-accent-1);
}

.sp-btn--outline:hover {
    background-color: var(--color-accent-1);
    color: var(--color-white);
}

/* Variant: ghost — light gray fill, gray border */
.sp-btn--ghost {
    background-color: var(--color-gray-1);
    border-color: var(--color-gray-2);
    color: var(--color-gray-4);
}

.sp-btn--ghost:hover {
    background-color: var(--color-accent-1);
    border-color: var(--color-accent-1);
    color: var(--color-white);
}

/* Variant: subtle — transparent fill, gray border */
.sp-btn--subtle {
    background-color: transparent;
    border-color: var(--color-gray-2);
    color: var(--color-dark-text);
}

.sp-btn--subtle:hover {
    border-color: var(--color-accent-1);
    color: var(--color-accent-1);
}

/* Size: large — 16px text, extra padding, 10px radius (New Topic) */
.sp-btn--lg {
    font-size: 16px;
    padding: 12px 24px 12px 14px;
    border-radius: 10px;
}

/* Size: small — 13px text, compact padding */
.sp-btn--sm {
    font-size: 13px;
    padding: 8px 16px;
    border-radius: var(--radius);
    letter-spacing: 0.04em;
}

/* Modifier: full-width block button */
.sp-btn--block {
    display: flex;
    width: 100%;
    justify-content: center;
}