/* ============================================
   AINNA BUTTON SYSTEM
   Foundation-mapped universal buttons
   ============================================

   CATEGORIES (what the action means)
   ─────────────────────────────────────────────
   primary     → "Do the thing"         (--accent, solid fill)
   premium     → "Pay to do the thing"  (frosted slate glass + gold icon)
   destructive → "This can't be undone" (--danger, solid fill)
   secondary   → "Not the main action"  (border + text)
   ghost       → "Barely a button"      (text only)

   SIZES (where the button lives)
   ─────────────────────────────────────────────
   lg   → Landing pages, hero CTAs, pricing cards
   md   → In-app actions, modals, panels (DEFAULT)
   sm   → Toolbars, inline, cards, compact UI

   ICON MODES
   ─────────────────────────────────────────────
   [default]      → Label only
   .btn--icon     → Icon + label (adds gap, icon sizing)
   .btn--icon-only → Icon only, square aspect (toolbars)

   MODIFIERS (surface treatment)
   ─────────────────────────────────────────────
   .btn--gradient → Upgrades btn-primary to gradient CTA + accent glow
   .btn--on-dark  → Adapts btn-secondary for dark backgrounds
   .btn--pill     → Full-radius shape
   .btn--full     → 100% width

   SPECIAL: GOLD SHIMMER ICON
   ─────────────────────────────────────────────
   Add class .icon-gold to any <i> or <span> inside
   btn-premium or btn-secondary-premium for the
   animated gold shimmer effect.

   SPECIAL: PREMIUM BADGE (not a button)
   ─────────────────────────────────────────────
   <span class="premium-badge"><i class="fa-solid fa-star icon-gold"></i> PREMIUM</span>
   Text-based label for lock overlays. No button affordance.

   USAGE
   ─────────────────────────────────────────────
   <button class="btn btn-primary">Generate Deck</button>
   <button class="btn btn-primary btn--lg btn--pill btn--icon btn--gradient"><i class="fa-solid fa-sparkles"></i> Start Free Trial</button>
   <button class="btn btn-primary btn--pill btn--icon btn--gradient"><i class="fa-solid fa-arrow-right"></i> Try It Now</button>
   <button class="btn btn-secondary btn--pill btn--icon btn--full btn--on-dark"><i class="fa-solid fa-arrow-right"></i> Explore Plans</button>
   <button class="btn btn-premium btn--icon"><i class="fa-solid fa-sparkles icon-gold"></i> Purchase Venture Starter</button>
   <button class="btn btn-secondary-premium btn--sm btn--icon"><i class="fa-solid fa-arrow-right icon-gold"></i> Explore all plans</button>
   <button class="btn btn-secondary">Cancel</button>
   <button class="btn btn-ghost btn--sm">Learn more</button>
   <button class="btn btn-destructive btn--icon"><i class="fa-solid fa-trash"></i> Delete Idea</button>
   <button class="btn btn-secondary btn--sm btn--icon-only"><i class="fa-solid fa-download"></i></button>

   ============================================ */


/* ═══════════════════════════════════════════
   BASE — shared by all buttons
   ═══════════════════════════════════════════ */

.btn {
    /* Reset */
    appearance: none;
    border: none;
    background: none;
    cursor: pointer;
    outline: none;
    text-decoration: none;
    /* Layout */
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: 0;
    white-space: nowrap;
    /* Typography */
    font-family: var(--font);
    font-weight: var(--font-weight-semibold);
    line-height: 1;
    letter-spacing: 0.01em;
    /* Default size: md */
    height: 2.5rem;
    padding: 0 1.25rem;
    font-size: var(--text-sm);
    border-radius: var(--radius-md);
    /* Transitions */
    transition: background 0.2s ease, color 0.2s ease, border-color 0.2s ease, box-shadow 0.2s ease, transform 0.15s ease, opacity 0.2s ease;
}

    /* Focus ring — all categories */
    .btn:focus-visible {
        outline: 2px solid var(--accent);
        outline-offset: 2px;
    }

    /* Disabled — all categories */
    .btn:disabled,
    .btn[aria-disabled="true"] {
        opacity: 0.45;
        cursor: not-allowed;
        pointer-events: none;
    }


/* ═══════════════════════════════════════════
   SIZES
   ═══════════════════════════════════════════ */

.btn--lg {
    height: 3rem;
    padding: 0 1.75rem;
    font-size: var(--text-base);
    border-radius: var(--radius-lg);
}

.btn--sm {
    height: 2rem;
    padding: 0 0.875rem;
    font-size: var(--text-xs);
    border-radius: var(--radius-sm);
    letter-spacing: 0.015em;
}


/* ═══════════════════════════════════════════
   ICON MODES
   ═══════════════════════════════════════════ */

/* Icon + label */
.btn--icon {
    gap: 0.5rem;
}

    .btn--icon i,
    .btn--icon svg {
        font-size: 0.95em;
        flex-shrink: 0;
        line-height: 1;
    }

.btn--lg.btn--icon {
    gap: 0.625rem;
}

    .btn--lg.btn--icon i,
    .btn--lg.btn--icon svg {
        font-size: 1.05em;
    }

.btn--sm.btn--icon {
    gap: 0.375rem;
}

    .btn--sm.btn--icon i,
    .btn--sm.btn--icon svg {
        font-size: 0.85em;
    }

/* Icon only — square aspect */
.btn--icon-only {
    padding: 0;
    gap: 0;
}

    .btn--icon-only.btn--lg {
        width: 3rem;
    }

/* md (default) */
.btn--icon-only {
    width: 2.5rem;
}

    .btn--icon-only.btn--sm {
        width: 2rem;
    }

    .btn--icon-only i,
    .btn--icon-only svg {
        font-size: 1.1em;
    }


/* ═══════════════════════════════════════════
   MIN-WIDTH — Consistent sizing for icon+label
   All buttons of the same size class land at
   the same width regardless of category
   ═══════════════════════════════════════════ */

.btn--icon:not(.btn--icon-only):not(.btn--pill) {
    min-width: 8.5rem;
}

.btn--lg.btn--icon:not(.btn--icon-only):not(.btn--pill) {
    min-width: 10rem;
}

.btn--sm.btn--icon:not(.btn--icon-only):not(.btn--pill) {
    min-width: 6.5rem;
}


/* ═══════════════════════════════════════════
   PREMIUM BADGE — Text label, not a button
   For: lock overlay "★ PREMIUM" text
   Usage: <span class="premium-badge">★ PREMIUM</span>
   ═══════════════════════════════════════════ */

.premium-badge {
    display: inline-flex;
    align-items: center;
    gap: 0.375rem;
    font-family: var(--font);
    font-size: var(--text-xs);
    font-weight: var(--font-weight-bold);
    letter-spacing: 0.06em;
    text-transform: uppercase;
    color: var(--premium-dark);
    margin-bottom: 0.75rem;
}

    /* Size override only — use color for FA icon compatibility */
    .premium-badge .icon-gold {
        font-size: 1.1em;
        background: none;
        -webkit-background-clip: unset;
        -webkit-text-fill-color: unset;
        background-clip: unset;
        animation: none;
        color: var(--premium-gold);
    }

    /* Gold color for FA icons inside premium badge */
    .premium-badge i.fas,
    .premium-badge i.far {
        color: var(--premium-gold);
    }

/* Available/unlocked variant — same layout, softer presence */
.premium-badge--available {
    color: var(--premium-light);
}


/* ═══════════════════════════════════════════
   CATEGORY: PRIMARY
   "Do the thing"
   ═══════════════════════════════════════════ */

.btn-primary {
    background: var(--accent);
    color: #ffffff;
    box-shadow: 0 1px 2px var(--accent-shadow);
}

    .btn-primary:hover {
        background: var(--accent-hover);
        transform: translateY(-1px);
        box-shadow: 0 4px 12px var(--accent-shadow);
    }

    .btn-primary:active {
        background: var(--accent-deep);
        transform: translateY(0);
        box-shadow: 0 1px 2px var(--accent-shadow);
    }

    .btn-primary:focus-visible {
        outline-color: var(--accent);
    }


/* ═══════════════════════════════════════════
   CATEGORY: PREMIUM
   "Pay to do the thing"
   ═══════════════════════════════════════════ */

.btn-premium {
    background: var(--premium-surface);
    backdrop-filter: blur(12px);
    -webkit-backdrop-filter: blur(12px);
    color: var(--premium-dark);
    border: 1px solid var(--premium-border);
    box-shadow: 0 2px 8px color-mix(in srgb, var(--premium) 6%, transparent), inset 0 1px 0 rgba(255, 255, 255, 0.55);
}

    .btn-premium:hover {
        background: color-mix(in srgb, var(--premium) 10%, transparent);
        border-color: color-mix(in srgb, var(--premium) 25%, transparent);
        transform: translateY(-2px);
        box-shadow: 0 4px 16px color-mix(in srgb, var(--premium) 10%, transparent), inset 0 1px 0 rgba(255, 255, 255, 0.55);
    }

    .btn-premium:active {
        background: color-mix(in srgb, var(--premium) 12%, transparent);
        transform: translateY(0);
        box-shadow: 0 1px 4px color-mix(in srgb, var(--premium) 6%, transparent), inset 0 1px 0 rgba(255, 255, 255, 0.4);
    }

    .btn-premium:focus-visible {
        outline-color: var(--premium);
    }

    /* Gold color for FA icons inside premium buttons */
    .btn-premium i.fas,
    .btn-premium i.far {
        color: var(--premium-gold);
    }


/* ═══════════════════════════════════════════
   CATEGORY: DESTRUCTIVE
   "This can't be undone"
   ═══════════════════════════════════════════ */

.btn-destructive {
    background: var(--danger);
    color: #ffffff;
    box-shadow: 0 1px 2px color-mix(in srgb, var(--danger) 20%, transparent);
}

    .btn-destructive:hover {
        background: var(--danger-dark);
        transform: translateY(-1px);
        box-shadow: 0 4px 12px color-mix(in srgb, var(--danger) 20%, transparent);
    }

    .btn-destructive:active {
        background: color-mix(in srgb, var(--danger-dark) 85%, #000000);
        transform: translateY(0);
        box-shadow: 0 1px 2px color-mix(in srgb, var(--danger) 15%, transparent);
    }

    .btn-destructive:focus-visible {
        outline-color: var(--danger);
    }


/* ═══════════════════════════════════════════
   CATEGORY: SECONDARY
   "Not the main action"
   ═══════════════════════════════════════════ */

.btn-secondary {
    background: transparent;
    color: var(--text-primary);
    border: 1px solid var(--border-color);
}

    .btn-secondary:hover {
        background: var(--background-secondary);
        border-color: var(--border-strong);
        transform: translateY(-1px);
    }

    .btn-secondary:active {
        background: var(--background-tertiary);
        transform: translateY(0);
    }

    .btn-secondary:focus-visible {
        outline-color: var(--accent);
    }


/* ═══════════════════════════════════════════
   CATEGORY: GHOST
   "Barely a button"
   ═══════════════════════════════════════════ */

.btn-ghost {
    background: transparent;
    color: var(--text-secondary);
    padding-left: 0.5rem;
    padding-right: 0.5rem;
}

    .btn-ghost:hover {
        color: var(--text-primary);
        background: var(--background-secondary);
    }

    .btn-ghost:active {
        color: var(--text-primary);
        background: var(--background-tertiary);
    }

    .btn-ghost:focus-visible {
        outline-color: var(--accent);
    }


/* ═══════════════════════════════════════════
   VARIANT: SECONDARY-ACCENT
   Secondary outline but tinted toward accent
   For: "View plans", "See pricing" — soft CTAs
   ═══════════════════════════════════════════ */

.btn-secondary-accent {
    background: transparent;
    color: var(--accent);
    border: 1px solid var(--accent-border);
}

    .btn-secondary-accent:hover {
        background: var(--accent-subtle);
        border-color: color-mix(in srgb, var(--accent) 35%, transparent);
        transform: translateY(-1px);
    }

    .btn-secondary-accent:active {
        background: color-mix(in srgb, var(--accent) 12%, transparent);
        transform: translateY(0);
    }

    .btn-secondary-accent:focus-visible {
        outline-color: var(--accent);
    }


/* ═══════════════════════════════════════════
   VARIANT: SECONDARY-PREMIUM
   Lighter glass — for "Explore plans", "Compare tiers"
   ═══════════════════════════════════════════ */

.btn-secondary-premium {
    background: transparent;
    color: var(--premium);
    border: none;
}

    .btn-secondary-premium:hover {
        color: var(--premium-dark);
        transform: translateY(-1px);
    }

    .btn-secondary-premium:active {
        background: color-mix(in srgb, var(--premium) 8%, transparent);
        transform: translateY(0);
    }

    .btn-secondary-premium:focus-visible {
        outline-color: var(--premium);
    }

/* Gold shimmer icon inherits from base .icon-gold */


/* ═══════════════════════════════════════════
   MODIFIER: GRADIENT
   Upgrades btn-primary to gradient CTA + glow
   For: hero CTAs, section CTAs, pricing actions
   ═══════════════════════════════════════════ */

.btn-primary.btn--gradient {
    background: var(--gradient-cta);
    box-shadow: var(--accent-glow-sm);
    transition: background 0.2s ease, color 0.2s ease, box-shadow 0.3s cubic-bezier(0.16, 1, 0.3, 1), transform 0.15s ease, opacity 0.2s ease;
}

    .btn-primary.btn--gradient:hover {
        background: var(--gradient-cta);
        box-shadow: var(--accent-glow);
        transform: translateY(-2px);
    }

    .btn-primary.btn--gradient:active {
        box-shadow: var(--accent-glow-sm);
        transform: translateY(0);
    }

    .btn-primary.btn--gradient:focus-visible {
        outline-color: var(--accent);
    }


/* ═══════════════════════════════════════════
   MODIFIER: ON-DARK
   Adapts btn-secondary for dark backgrounds
   For: pricing cards, dark sections, footer
   ═══════════════════════════════════════════ */

.btn-secondary.btn--on-dark {
    color: var(--on-dark-btn-text);
    background: var(--on-dark-btn-bg);
    border-color: var(--on-dark-btn-border);
}

    .btn-secondary.btn--on-dark:hover {
        background: var(--on-dark-btn-bg-hover);
        border-color: var(--on-dark-btn-border-hover);
        color: #fff;
        transform: translateY(-1px);
    }

    .btn-secondary.btn--on-dark:active {
        background: var(--on-dark-btn-bg);
        transform: translateY(0);
    }

    .btn-secondary.btn--on-dark:focus-visible {
        outline-color: rgba(255, 255, 255, 0.4);
    }

    .btn-secondary.btn--on-dark i {
        transition: transform 0.2s ease;
    }

    .btn-secondary.btn--on-dark:hover i {
        transform: translateX(3px);
    }


/* ═══════════════════════════════════════════
   SHAPE: PILL
   Full-radius for toolbar/control buttons
   ═══════════════════════════════════════════ */

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


/* ═══════════════════════════════════════════
   STATE: LOADING
   Applied alongside any category
   ═══════════════════════════════════════════ */

.btn--loading {
    pointer-events: none;
    position: relative;
    color: transparent !important;
}

    .btn--loading::after {
        content: '';
        position: absolute;
        width: 1.125em;
        height: 1.125em;
        border: 2px solid currentColor;
        border-right-color: transparent;
        border-radius: 50%;
        animation: btn-spin 0.6s linear infinite;
    }

/* Restore visible color for spinner inheritance */
.btn-primary.btn--loading::after,
.btn-primary.btn--gradient.btn--loading::after,
.btn-destructive.btn--loading::after {
    border-color: rgba(255, 255, 255, 0.35);
    border-right-color: #ffffff;
}

.btn-premium.btn--loading::after,
.btn-secondary.btn--loading::after,
.btn-ghost.btn--loading::after {
    border-color: color-mix(in srgb, var(--text-tertiary) 40%, transparent);
    border-right-color: var(--text-secondary);
}

@keyframes btn-spin {
    to {
        transform: rotate(360deg);
    }
}

@keyframes btn-gold-shimmer {
    0% {
        background-position: -200% center;
    }

    100% {
        background-position: 200% center;
    }
}

/* Base gold shimmer — works on FA icons and text */
.icon-gold {
    background: linear-gradient(90deg, var(--premium-gold), var(--premium-gold-light), var(--premium-gold));
    background-size: 200% 100%;
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
    animation: btn-gold-shimmer 3s linear infinite;
    font-style: normal;
}


/* ═══════════════════════════════════════════
   STATE: FULL WIDTH
   ═══════════════════════════════════════════ */

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


/* ═══════════════════════════════════════════
   REDUCED MOTION
   ═══════════════════════════════════════════ */

@media (prefers-reduced-motion: reduce) {
    .btn {
        transition: none;
    }

        .btn:hover,
        .btn:active {
            transform: none;
        }

    .btn--loading::after {
        animation: none;
    }

    .icon-gold,
    .premium-badge .icon-gold {
        animation: none;
    }
}