:root {
    --primary: #0284c7; /* Sky Blue - Màu chủ đạo chuyên nghiệp của Quang Nguyễn */
    --primary-hover: #0369a1;
    --success-accent: #059669; /* Emerald Green - Sạch sẽ, sinh thái */
    --dark: #0f172a;
    --light-bg: #f8fafc;
    --text-muted: #64748b;
    --transition: all 0.3s ease;
}

body {
    font-family: 'Inter', sans-serif;
    color: var(--dark);
    overflow-x: hidden;
    background-color: #ffffff;
}

/* Tối ưu hóa chuyển động mượt */
html {
    scroll-behavior: smooth;
}

/* Tiêu đề trang trí */
.section-title {
    position: relative;
    padding-bottom: 15px;
    margin-bottom: 30px;
    font-weight: 700;
}

    .section-title::after {
        content: '';
        position: absolute;
        bottom: 0;
        left: 50%;
        transform: translateX(-50%);
        width: 80px;
        height: 4px;
        background: linear-gradient(90deg, var(--primary), var(--success-accent));
        border-radius: 2px;
    }

    .section-title.text-start::after {
        left: 0;
        transform: none;
    }

/* Navbar Custom */
.navbar {
    transition: var(--transition);
    box-shadow: 0 2px 15px rgba(0,0,0,0.05);
}

.navbar-brand {
    font-weight: 800;
    font-size: 1.5rem;
    background: linear-gradient(135deg, var(--primary), var(--success-accent));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
}

.nav-link {
    font-weight: 500;
    color: var(--dark) !important;
    transition: var(--transition);
    position: relative;
}

    .nav-link:hover, .nav-link.active {
        color: var(--primary) !important;
    }

    .nav-link::after {
        content: '';
        position: absolute;
        width: 0;
        height: 2px;
        bottom: 0;
        left: 50%;
        background-color: var(--primary);
        transition: var(--transition);
        transform: translateX(-50%);
    }

    .nav-link:hover::after {
        width: 80%;
    }

/* Hero Banner Section */
.hero-section {
    background: linear-gradient(135deg, rgba(2, 132, 199, 0.05) 0%, rgba(5, 150, 105, 0.05) 100%), url('https://images.unsplash.com/photo-1628177142898-93e36e4e3a50?auto=format&fit=crop&w=1920&q=80') no-repeat center center/cover;
    padding: 160px 0 100px 0;
    position: relative;
}

.hero-card {
    background: rgba(255, 255, 255, 0.95);
    backdrop-filter: blur(10px);
    border-radius: 20px;
    border: 1px solid rgba(255, 255, 255, 0.5);
    box-shadow: 0 10px 30px rgba(15, 23, 42, 0.08);
}

/* Stats Badge */
.stat-badge {
    background: rgba(2, 132, 199, 0.1);
    color: var(--primary);
    padding: 8px 16px;
    border-radius: 50px;
    font-weight: 600;
    font-size: 0.9rem;
    display: inline-flex;
    align-items: center;
    gap: 8px;
    margin-bottom: 20px;
}

/* Cards & Hover Effects */
.hover-card {
    border: none;
    border-radius: 16px;
    transition: var(--transition);
    background: #fff;
    box-shadow: 0 4px 20px rgba(0,0,0,0.03);
}

    .hover-card:hover {
        transform: translateY(-10px);
        box-shadow: 0 12px 30px rgba(2, 132, 199, 0.12);
    }

.icon-box {
    width: 60px;
    height: 60px;
    background: rgba(2, 132, 199, 0.1);
    color: var(--primary);
    border-radius: 12px;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 1.5rem;
    margin-bottom: 20px;
    transition: var(--transition);
}

.hover-card:hover .icon-box {
    background: var(--primary);
    color: #fff;
}

/* Pricing & Calculator */
.calculator-container {
    background: #ffffff;
    border-radius: 24px;
    border: 2px solid #f1f5f9;
    box-shadow: 0 15px 40px rgba(0,0,0,0.05);
}

.custom-range::-webkit-slider-thumb {
    background: var(--primary);
}

/* Step workflow */
.step-circle {
    width: 50px;
    height: 50px;
    background: var(--primary);
    color: #fff;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-weight: 700;
    font-size: 1.2rem;
    margin: 0 auto 20px auto;
    border: 4px solid #fff;
    box-shadow: 0 0 0 4px rgba(2, 132, 199, 0.2);
}

/* Testimonials */
.testimonial-card {
    border-radius: 16px;
    background-color: var(--light-bg);
    padding: 30px;
    position: relative;
}

    .testimonial-card::before {
        content: "\f2cf";
        font-family: "bootstrap-icons";
        position: absolute;
        top: 20px;
        right: 25px;
        font-size: 3rem;
        color: rgba(2, 132, 199, 0.08);
    }

/* Floating Contact Elements */
.floating-group {
    position: fixed;
    bottom: 30px;
    right: 30px;
    z-index: 1050;
    display: flex;
    flex-direction: column;
    gap: 15px;
}

.btn-float {
    width: 56px;
    height: 56px;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    color: #fff;
    font-size: 1.6rem;
    box-shadow: 0 4px 15px rgba(0,0,0,0.2);
    transition: var(--transition);
    text-decoration: none;
}

    .btn-float:hover {
        transform: scale(1.1);
        color: #fff;
    }

.btn-phone {
    background-color: #ef4444;
    animation: pulse-ring 1.5s infinite;
}

.btn-zalo {
    background-color: #0068ff;
}

@keyframes pulse-ring {
    0% {
        box-shadow: 0 0 0 0 rgba(239, 68, 68, 0.7);
    }

    70% {
        box-shadow: 0 0 0 15px rgba(239, 68, 68, 0);
    }

    100% {
        box-shadow: 0 0 0 0 rgba(239, 68, 68, 0);
    }
}

/* Lazy / placeholder styled images */
.img-placeholder {
    background-color: #e2e8f0;
    border-radius: 16px;
    overflow: hidden;
    position: relative;
    min-height: 250px;
}

/* FOOTER DECORATION & WATERMARK */
footer {
    position: relative;
    overflow: hidden;
    background-color: #1e293b !important; /* Màu xám đậm sang trọng giống ảnh mẫu */
}

.footer-watermark {
    position: absolute;
    top: 15%;
    left: 5%;
    width: 450px;
    height: auto;
    opacity: 0.1; /* Hiệu ứng watermark chìm mờ */
    pointer-events: none;
    z-index: 0;
    transform: rotate(-12deg);
    filter: brightness(0) invert(1);
}

footer .container {
    position: relative;
    z-index: 1; /* Hiển thị nội dung đè lên watermark */
}

footer a {
    transition: var(--transition);
}

    footer a:hover {
        color: var(--primary) !important;
    }