/* =================================================================
   BUTTONS — Unified button system v4.2
   All variant/size classes are self-contained — no .btn base required.
   ================================================================= */

/* ── Shared layout (applied to ALL button classes) ── */
.btn,
.btn-primary,
.btn-outline,
.btn-secondary,
.btn-success,
.btn-warning,
.btn-danger,
.btn-ghost,
.btn-sm, .btn-xs, .btn-lg,
.btn-block {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: 8px;
    padding: 10px 22px;
    border: none;
    border-radius: var(--radius-sm);
    font-size: 0.9rem;
    font-weight: 600;
    font-family: inherit;
    cursor: pointer;
    transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
    white-space: nowrap;
    letter-spacing: -0.01em;
    position: relative;
    overflow: hidden;
    text-decoration: none;
    user-select: none;
    -webkit-tap-highlight-color: transparent;
}

.btn::before,
.btn-primary::before, .btn-outline::before, .btn-secondary::before,
.btn-success::before, .btn-warning::before, .btn-danger::before, .btn-ghost::before {
    content: '';
    position: absolute;
    inset: 0;
    background: linear-gradient(to bottom, rgba(255,255,255,0.15), transparent);
    opacity: 0;
    transition: opacity 0.3s ease;
    pointer-events: none;
}
.btn::after,
.btn-primary::after, .btn-outline::after, .btn-secondary::after,
.btn-success::after, .btn-warning::after, .btn-danger::after, .btn-ghost::after {
    content: '';
    position: absolute;
    top: 50%; left: 50%;
    width: 0; height: 0;
    background: rgba(255,255,255,0.25);
    border-radius: 50%;
    transform: translate(-50%, -50%);
    transition: width 0.6s ease, height 0.6s ease;
    pointer-events: none;
}
.btn:hover::before,
.btn-primary:hover::before, .btn-outline:hover::before, .btn-secondary:hover::before,
.btn-success:hover::before, .btn-warning:hover::before, .btn-danger:hover::before, .btn-ghost:hover::before { opacity: 1; }
.btn:active::after,
.btn-primary:active::after, .btn-outline:active::after, .btn-secondary:active::after,
.btn-success:active::after, .btn-warning:active::after, .btn-danger:active::after, .btn-ghost:active::after { width: 300px; height: 300px; }

.btn:focus-visible,
.btn-primary:focus-visible, .btn-outline:focus-visible, .btn-secondary:focus-visible,
.btn-success:focus-visible, .btn-warning:focus-visible, .btn-danger:focus-visible, .btn-ghost:focus-visible {
    outline: 2px solid var(--accent);
    outline-offset: 3px;
    border-radius: var(--radius-sm);
}

/* ── Variants ── */
.btn-primary {
    background: linear-gradient(135deg, var(--accent) 0%, var(--color-brand-400) 100%);
    color: #fff;
    box-shadow: 0 4px 14px rgba(37, 99, 235, 0.35), 0 2px 6px rgba(37, 99, 235, 0.2),
                inset 0 1px 0 rgba(255,255,255,0.15);
}
.btn-primary:hover {
    background: linear-gradient(135deg, var(--accent-hover) 0%, var(--color-brand-500) 100%);
    box-shadow: 0 8px 24px rgba(37, 99, 235, 0.45), 0 4px 12px rgba(37, 99, 235, 0.25),
                inset 0 1px 0 rgba(255,255,255,0.2);
    transform: translateY(-3px);
}
.btn-primary:active { transform: translateY(-1px) scale(0.98); box-shadow: 0 2px 8px rgba(37, 99, 235, 0.3); }
.btn-primary:disabled, .btn-primary[disabled] {
    background: linear-gradient(135deg, #CBD5E1 0%, #94A3B8 100%);
    cursor: not-allowed; transform: none !important; box-shadow: none; opacity: 0.7;
}

.btn-secondary {
    background: linear-gradient(135deg, var(--secondary) 0%, var(--color-gray-600) 100%);
    color: #fff;
    box-shadow: 0 4px 12px rgba(51, 65, 85, 0.3), 0 2px 4px rgba(51, 65, 85, 0.2);
}
.btn-secondary:hover {
    background: linear-gradient(135deg, var(--color-gray-700) 0%, var(--primary) 100%);
    box-shadow: 0 6px 18px rgba(51, 65, 85, 0.4);
    transform: translateY(-2px);
}
.btn-secondary:active { transform: translateY(0) scale(0.98); }

.btn-success {
    background: linear-gradient(135deg, var(--success) 0%, var(--color-success-600) 100%);
    color: #fff;
    box-shadow: 0 4px 12px rgba(16, 185, 129, 0.35), 0 2px 4px rgba(16, 185, 129, 0.2);
}
.btn-success:hover {
    background: linear-gradient(135deg, var(--color-success-600) 0%, var(--color-success-700) 100%);
    box-shadow: 0 6px 18px rgba(16, 185, 129, 0.45);
    transform: translateY(-2px);
}
.btn-success:active { transform: translateY(0) scale(0.98); }

.btn-warning {
    background: linear-gradient(135deg, var(--warning) 0%, var(--color-warning-600) 100%);
    color: #fff;
    box-shadow: 0 4px 12px rgba(245, 158, 11, 0.35), 0 2px 4px rgba(245, 158, 11, 0.2);
}
.btn-warning:hover {
    background: linear-gradient(135deg, var(--color-warning-600) 0%, var(--color-warning-700) 100%);
    box-shadow: 0 6px 18px rgba(245, 158, 11, 0.45);
    transform: translateY(-2px);
}
.btn-warning:active { transform: translateY(0) scale(0.98); }

.btn-danger {
    background: linear-gradient(135deg, var(--danger) 0%, var(--color-danger-600) 100%);
    color: #fff;
    box-shadow: 0 3px 10px rgba(239, 68, 68, 0.3), 0 1px 3px rgba(239, 68, 68, 0.2);
}
.btn-danger:hover {
    background: linear-gradient(135deg, var(--color-danger-600) 0%, var(--color-danger-700) 100%);
    transform: translateY(-2px);
    box-shadow: 0 5px 16px rgba(220, 38, 38, 0.4);
}
.btn-danger:active { transform: translateY(0) scale(0.97); }

.btn-outline {
    background: var(--surface);
    color: var(--text-secondary);
    border: 2px solid var(--border);
    box-shadow: var(--shadow-sm), inset 0 1px 0 rgba(255,255,255,0.5);
}
.btn-outline:hover {
    border-color: var(--accent);
    color: var(--accent);
    background: var(--accent-light);
    box-shadow: 0 6px 20px rgba(37, 99, 235, 0.15), 0 2px 6px rgba(37, 99, 235, 0.08);
    transform: translateY(-2px);
}
.btn-outline:active { transform: translateY(0) scale(0.98); }

.btn-ghost {
    background: transparent;
    color: var(--text-secondary);
    border: 2px solid transparent;
}
.btn-ghost:hover {
    background: var(--border-light);
    color: var(--text);
    border-color: var(--border);
}

/* ── Sizes ── */
.btn-sm, .btn-sm.btn-primary, .btn-sm.btn-outline, .btn-sm.btn-secondary,
.btn-sm.btn-success, .btn-sm.btn-warning, .btn-sm.btn-danger, .btn-sm.btn-ghost {
    padding: 7px 16px;
    font-size: 0.82rem;
    border-radius: var(--radius-xs);
    font-weight: 600;
}
.btn-xs, .btn-xs.btn-primary, .btn-xs.btn-outline, .btn-xs.btn-secondary,
.btn-xs.btn-success, .btn-xs.btn-warning, .btn-xs.btn-danger, .btn-xs.btn-ghost {
    padding: 4px 10px;
    font-size: 0.75rem;
    border-radius: var(--radius-xs);
    font-weight: 600;
}
.btn-lg, .btn-lg.btn-primary, .btn-lg.btn-outline, .btn-lg.btn-secondary,
.btn-lg.btn-success, .btn-lg.btn-warning, .btn-lg.btn-danger, .btn-lg.btn-ghost {
    padding: 14px 32px;
    font-size: 1rem;
    border-radius: var(--radius-sm);
    font-weight: 700;
    letter-spacing: -0.02em;
}
.btn-block {
    width: 100%;
    justify-content: center;
}

/* ── Loading state ── */
.btn.loading,
.btn-primary.loading, .btn-outline.loading, .btn-secondary.loading,
.btn-success.loading, .btn-warning.loading, .btn-danger.loading, .btn-ghost.loading {
    pointer-events: none;
    position: relative;
    color: transparent !important;
}
.btn.loading::after,
.btn-primary.loading::after, .btn-outline.loading::after, .btn-secondary.loading::after,
.btn-success.loading::after, .btn-warning.loading::after, .btn-danger.loading::after, .btn-ghost.loading::after {
    content: '';
    position: absolute;
    top: 50%; left: 50%;
    width: 18px; height: 18px;
    margin: -9px 0 0 -9px;
    border: 2.5px solid rgba(255,255,255,0.3);
    border-top-color: currentColor;
    border-radius: 50%;
    animation: btnSpin 0.7s linear infinite;
}
@keyframes btnSpin { to { transform: rotate(360deg); } }