/* TechNex AI Tools — Design system thống nhất (#5B5FF8) */
:root {
    --tn-accent: #5B5FF8;
    --tn-accent-soft: rgba(91, 95, 248, 0.1);
    --tn-accent-glow: rgba(91, 95, 248, 0.35);
    --tn-success: #16a34a;
    --tn-surface: #ffffff;
    --tn-muted: #64748b;
    --tn-border: #e2e8f0;
    --tn-radius-lg: 20px;
    --tn-radius-md: 14px;
    --tn-radius-sm: 12px;
    --tn-shadow: 0 8px 32px rgba(15, 23, 42, 0.06);
    --tn-font: 'Inter', system-ui, -apple-system, sans-serif;
}

[class$="-card"],
.bgr-card,
.converter-box {
    font-family: var(--tn-font);
}

[class$="-card"] {
    width: 100%;
    max-width: 860px;
    background: var(--tn-surface);
    border: 1px solid #e8ecf1;
    border-radius: var(--tn-radius-lg);
    padding: 36px 32px;
    box-shadow: var(--tn-shadow);
    box-sizing: border-box;
}

[class$="-head"] h1,
.bgr-head h1 {
    margin: 0 0 8px;
    font-size: clamp(22px, 3vw, 32px);
    font-weight: 700;
    letter-spacing: -0.02em;
    color: var(--text, #0f172a);
}

[class$="-head"] p,
.bgr-head p {
    margin: 0;
    font-size: 14px;
    line-height: 1.5;
    color: var(--tn-muted);
}

/* AI prompt panel — inject bởi paint-tool.js */
.paint-ai-panel {
    margin: 0 0 16px;
    padding: 16px 18px;
    border-radius: var(--tn-radius-md);
    border: 1px solid var(--tn-border);
    background: linear-gradient(135deg, #fafbff 0%, #f8fafc 100%);
    animation: tnFadeIn 0.35s ease-out;
}

@keyframes tnFadeIn {
    from { opacity: 0; transform: translateY(8px); }
    to { opacity: 1; transform: translateY(0); }
}

.paint-ai-panel__label {
    display: flex;
    align-items: center;
    gap: 8px;
    margin: 0 0 8px;
    font-size: 13px;
    font-weight: 600;
    color: var(--tn-accent);
}

.paint-ai-panel__label svg {
    flex-shrink: 0;
}

.paint-ai-panel__hint {
    margin: 0 0 10px;
    font-size: 12px;
    color: var(--tn-muted);
    line-height: 1.45;
}

.paint-ai-prompt {
    width: 100%;
    min-height: 72px;
    max-height: 140px;
    padding: 12px 14px;
    border: 1px solid var(--tn-border);
    border-radius: var(--tn-radius-sm);
    font-family: inherit;
    font-size: 14px;
    line-height: 1.45;
    resize: vertical;
    box-sizing: border-box;
    transition: border-color 0.2s, box-shadow 0.2s;
    background: #fff;
}

.paint-ai-prompt:focus {
    outline: none;
    border-color: var(--tn-accent);
    box-shadow: 0 0 0 3px var(--tn-accent-soft);
}

.paint-ai-chips {
    display: flex;
    flex-wrap: wrap;
    gap: 8px;
    margin-top: 10px;
}

.paint-ai-chip {
    padding: 6px 12px;
    border-radius: 999px;
    border: 1px solid var(--tn-border);
    background: #fff;
    font-size: 12px;
    font-weight: 500;
    color: #475569;
    cursor: pointer;
    transition: border-color 0.15s, background 0.15s, color 0.15s;
}

.paint-ai-chip:hover {
    border-color: var(--tn-accent);
    color: var(--tn-accent);
    background: var(--tn-accent-soft);
}

[class$="-drop"],
.drop-zone {
    display: block;
    border: 2px dashed #d1d5db;
    border-radius: var(--tn-radius-md);
    padding: 44px 24px;
    text-align: center;
    cursor: pointer;
    background: #f9fafb;
    transition: border-color 0.2s, background 0.2s, transform 0.2s;
}

[class$="-drop"]:hover,
[class$="-drop"].is-dragover,
.drop-zone:hover,
.drop-zone.dragover {
    border-color: var(--tn-accent);
    background: var(--tn-accent-soft);
}

[class$="-btn"],
.tool-btn,
.bgr-btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: 8px;
    height: 44px;
    padding: 0 20px;
    border-radius: var(--tn-radius-sm);
    font-size: 14px;
    font-weight: 600;
    cursor: pointer;
    transition: opacity 0.2s, transform 0.2s, box-shadow 0.2s;
    border: none;
    font-family: inherit;
}

[class$="-btn--primary"],
.bgr-btn-primary {
    flex: 1;
    min-width: 160px;
    background: linear-gradient(135deg, var(--tn-accent) 0%, #7c80ff 100%);
    color: #fff;
    box-shadow: 0 4px 14px var(--tn-accent-glow);
}

[class$="-btn--primary"]:hover:not(:disabled),
.bgr-btn-primary:hover:not(:disabled) {
    opacity: 0.95;
    transform: translateY(-1px);
}

[class$="-btn--ghost"] {
    background: #fff;
    border: 1px solid var(--tn-border);
    color: #475569;
}

[class$="-btn--download"] {
    background: var(--tn-success);
    color: #fff;
    text-decoration: none;
}

[class$="-progress__fill"] {
    background: linear-gradient(90deg, var(--tn-accent), #9aa0ff) !important;
}

[class$="-progress__bar"] {
    background: #eef2ff !important;
    border: 1px solid #e0e7ff !important;
}

/* Desktop ≥1024 */
@media (min-width: 1024px) {
    .main-container-app {
        padding: 56px 32px 72px;
    }

    [class$="-card"] {
        padding: 40px 40px;
    }

    .paint-ai-panel {
        padding: 18px 22px;
    }
}

/* Mobile + Tablet <1024 */
@media (max-width: 1023px) {
    .main-container-app {
        padding: 32px 16px 48px;
    }

    [class$="-card"] {
        padding: 24px 16px;
        border-radius: 16px;
    }

    [class$="-actions"],
    .bgr-actions {
        flex-direction: column;
    }

    [class$="-btn"],
    .bgr-btn {
        width: 100%;
    }

    [class$="-toolbar"] {
        flex-direction: column;
        align-items: stretch;
    }

    .paint-ai-chips {
        gap: 6px;
    }

    .paint-ai-chip {
        font-size: 11px;
        padding: 5px 10px;
    }
}

@media (prefers-reduced-motion: reduce) {
    .paint-ai-panel { animation: none; }
    [class$="-btn"] { transition: none; }
}