body {
    font-family: 'Inter', sans-serif;
    background-color: #f3f4f6;
    /* Nền xám nhẹ cho PC */
    color: #111827;
    /* Chống cuộn trang trên mobile khi kéo thả */
    overscroll-behavior: none;
}

/* Ẩn scrollbar nhưng vẫn cho cuộn nội dung nếu cần */
.no-scrollbar::-webkit-scrollbar {
    display: none;
}

.no-scrollbar {
    -ms-overflow-style: none;
    scrollbar-width: none;
}

/* Cấu hình để Canvas không bị giật khi chạm trên mobile */
canvas {
    touch-action: none;
}

.glass-panel {
    background: rgba(255, 255, 255, 0.85);
    backdrop-filter: blur(12px);
    -webkit-backdrop-filter: blur(12px);
}

/* Hiệu ứng focus */
input:focus {
    outline: none;
    border-color: #000000;
    box-shadow: 0 0 0 1px #000000;
}

/* Header & Brand Styles */
.btn-back {
    width: 38px;
    height: 38px;
    display: inline-flex;
    align-items: center;
    justify-content: center;
    border-radius: 12px;
    background: rgba(0, 0, 0, 0.04);
    border: 1.5px solid rgba(0, 0, 0, 0.22);
    color: #1f2937;
    text-decoration: none;
    transition: all 0.2s cubic-bezier(0.16, 1, 0.3, 1);
    cursor: pointer;
    flex-shrink: 0;
}

.btn-back:hover {
    background: rgba(0, 0, 0, 0.08);
    color: #000000;
    transform: translateX(-2px);
    border-color: rgba(0, 0, 0, 0.45);
}

.btn-back:active {
    transform: scale(0.92);
    background: rgba(0, 0, 0, 0.12);
    border-color: rgba(0, 0, 0, 0.55);
    opacity: 0.85;
}

.brand-link {
    display: inline-flex;
    align-items: center;
    gap: 10px;
    text-decoration: none;
    color: inherit;
    transition: opacity 0.15s ease;
}

.brand-link:hover {
    opacity: 0.92;
}

.brand-logo-card {
    width: 36px;
    height: 36px;
    border-radius: 10px;
    background: #ffffff;
    display: flex;
    align-items: center;
    justify-content: center;
    box-shadow: 0 1px 3px rgba(0, 0, 0, 0.1), 0 0 0 1px rgba(0, 0, 0, 0.06);
    flex-shrink: 0;
    padding: 3.5px;
    box-sizing: border-box;
    transition: transform 0.2s ease;
}

.brand-link:hover .brand-logo-card {
    transform: scale(1.04);
}

.brand-logo-img {
    width: 100%;
    height: 100%;
    object-fit: contain;
    border-radius: 6px;
    display: block;
}

.brand-text {
    display: inline-flex;
    align-items: center;
    gap: 7px;
    line-height: 1;
    white-space: nowrap;
}

.brand-name {
    font-weight: 800;
    font-size: 19px;
    color: #111827;
    letter-spacing: -0.025em;
    line-height: 1;
}

.brand-divider {
    font-size: 14px;
    font-weight: 300;
    color: #9ca3af;
    opacity: 0.7;
}

.brand-app {
    font-size: 14px;
    font-weight: 600;
    color: #4b5563;
    letter-spacing: -0.01em;
}

@media (max-width: 640px) {
    .btn-back {
        width: 34px;
        height: 34px;
        border-radius: 10px;
    }
    .brand-logo-card {
        width: 32px;
        height: 32px;
        border-radius: 8px;
        padding: 3px;
    }
    .brand-name {
        font-size: 17px;
    }
    .brand-app {
        font-size: 13px;
    }
}