/* ============================================================
   VIETNET.SHOP - Cho Thuê Máy Tính
   Main Stylesheet
   ============================================================ */

/* --- CSS Variables --- */
:root {
    --primary: #2563eb;
    --primary-dark: #1d4ed8;
    --primary-light: #dbeafe;
    --accent: #f59e0b;
    --accent-light: #fef3c7;
    --text: #1e293b;
    --text-light: #64748b;
    --bg: #ffffff;
    --bg-alt: #f8fafc;
    --bg-dark: #0f172a;
    --border: #e2e8f0;
    --shadow: 0 1px 3px rgba(0,0,0,0.08), 0 1px 2px rgba(0,0,0,0.06);
    --shadow-md: 0 4px 6px rgba(0,0,0,0.07), 0 2px 4px rgba(0,0,0,0.06);
    --shadow-lg: 0 10px 25px rgba(0,0,0,0.1), 0 4px 10px rgba(0,0,0,0.05);
    --radius: 12px;
    --radius-sm: 8px;
    --transition: 0.3s ease;
    --max-width: 1200px;
    --header-height: 72px;
}

/* --- Reset & Base --- */
*, *::before, *::after {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

html {
    scroll-behavior: smooth;
    scroll-padding-top: var(--header-height);
}

body {
    font-family: 'Segoe UI', 'Helvetica Neue', Arial, sans-serif;
    color: var(--text);
    background: var(--bg);
    line-height: 1.6;
    overflow-x: hidden;
}

a {
    text-decoration: none;
    color: inherit;
}

ul { list-style: none; }

img { max-width: 100%; display: block; }

.container {
    max-width: var(--max-width);
    margin: 0 auto;
    padding: 0 20px;
}

/* --- Buttons --- */
.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: 8px;
    padding: 12px 28px;
    font-size: 1rem;
    font-weight: 600;
    border-radius: var(--radius-sm);
    cursor: pointer;
    transition: all var(--transition);
    border: 2px solid transparent;
    white-space: nowrap;
}

.btn--primary {
    background: var(--primary);
    color: #fff;
}

.btn--primary:hover {
    background: var(--primary-dark);
    transform: translateY(-2px);
    box-shadow: var(--shadow-lg);
}

.btn--outline {
    background: transparent;
    color: var(--primary);
    border-color: var(--primary);
}

.btn--outline:hover {
    background: var(--primary);
    color: #fff;
    transform: translateY(-2px);
    box-shadow: var(--shadow-lg);
}

.btn--sm {
    padding: 8px 20px;
    font-size: 0.875rem;
}

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

/* --- Section Header --- */
.section-header {
    text-align: center;
    margin-bottom: 56px;
}

.section-header__tag {
    display: inline-block;
    background: var(--primary-light);
    color: var(--primary);
    padding: 6px 16px;
    border-radius: 50px;
    font-size: 0.875rem;
    font-weight: 600;
    margin-bottom: 16px;
}

.section-header__title {
    font-size: 2.25rem;
    font-weight: 800;
    color: var(--text);
    margin-bottom: 12px;
    line-height: 1.3;
}

.section-header__title--left {
    text-align: left;
}

.section-header__desc {
    font-size: 1.1rem;
    color: var(--text-light);
    max-width: 600px;
    margin: 0 auto;
}

/* ============================================================
   HEADER
   ============================================================ */
.header {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: var(--header-height);
    background: rgba(255,255,255,0.95);
    backdrop-filter: blur(10px);
    box-shadow: var(--shadow);
    z-index: 1000;
    transition: all var(--transition);
}

.header.scrolled {
    box-shadow: var(--shadow-md);
}

.header__inner {
    display: flex;
    align-items: center;
    justify-content: space-between;
    height: var(--header-height);
}

/* Logo */
.logo {
    display: flex;
    align-items: center;
    gap: 8px;
    font-size: 1.5rem;
    font-weight: 800;
    color: var(--text);
}

.logo__icon { font-size: 1.75rem; }

.logo__highlight {
    color: var(--primary);
}

/* Nav */
.nav__list {
    display: flex;
    gap: 32px;
}

.nav__link {
    font-size: 0.95rem;
    font-weight: 500;
    color: var(--text-light);
    transition: color var(--transition);
    position: relative;
}

.nav__link::after {
    content: '';
    position: absolute;
    bottom: -4px;
    left: 0;
    width: 0;
    height: 2px;
    background: var(--primary);
    transition: width var(--transition);
}

.nav__link:hover,
.nav__link.active {
    color: var(--primary);
}

.nav__link:hover::after,
.nav__link.active::after {
    width: 100%;
}

.header__actions {
    display: flex;
    align-items: center;
    gap: 16px;
}

.header__phone {
    font-weight: 700;
    color: var(--primary);
    font-size: 1rem;
    white-space: nowrap;
}

/* Hamburger */
.hamburger {
    display: none;
    flex-direction: column;
    gap: 5px;
    background: none;
    border: none;
    cursor: pointer;
    padding: 4px;
    z-index: 1001;
}

.hamburger span {
    display: block;
    width: 26px;
    height: 3px;
    background: var(--text);
    border-radius: 3px;
    transition: all var(--transition);
}

.hamburger.active span:nth-child(1) {
    transform: rotate(45deg) translate(5px, 6px);
}

.hamburger.active span:nth-child(2) {
    opacity: 0;
}

.hamburger.active span:nth-child(3) {
    transform: rotate(-45deg) translate(5px, -6px);
}

/* ============================================================
   HERO
   ============================================================ */
.hero {
    padding-top: calc(var(--header-height) + 60px);
    padding-bottom: 80px;
    background: linear-gradient(135deg, #eff6ff 0%, #f0f9ff 50%, #ecfdf5 100%);
    position: relative;
    overflow: hidden;
}

.hero__inner {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 60px;
    align-items: center;
}

.hero__badge {
    display: inline-block;
    background: var(--accent-light);
    color: #92400e;
    padding: 6px 16px;
    border-radius: 50px;
    font-size: 0.875rem;
    font-weight: 600;
    margin-bottom: 20px;
}

.hero__title {
    font-size: 3rem;
    font-weight: 800;
    line-height: 1.2;
    margin-bottom: 20px;
    color: var(--text);
}

.hero__title--accent {
    color: var(--primary);
}

.hero__desc {
    font-size: 1.125rem;
    color: var(--text-light);
    margin-bottom: 32px;
    max-width: 540px;
}

.hero__cta {
    display: flex;
    gap: 16px;
    margin-bottom: 48px;
}

.hero__stats {
    display: flex;
    gap: 40px;
}

.stat {
    display: flex;
    flex-direction: column;
}

.stat__number {
    font-size: 2rem;
    font-weight: 800;
    color: var(--primary);
    line-height: 1;
}

.stat__label {
    font-size: 0.875rem;
    color: var(--text-light);
    margin-top: 4px;
}

.hero__image {
    display: flex;
    justify-content: center;
}

.hero__img-wrapper {
    width: 100%;
    max-width: 500px;
    aspect-ratio: 4/3;
    background: var(--bg);
    border-radius: var(--radius);
    box-shadow: var(--shadow-lg);
    overflow: hidden;
}

.hero__placeholder {
    width: 100%;
    height: 100%;
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    background: linear-gradient(135deg, #f1f5f9, #e2e8f0);
    color: var(--text-light);
    font-size: 4rem;
}

.hero__placeholder p {
    font-size: 0.875rem;
    margin-top: 8px;
}

.hero__wave {
    position: absolute;
    bottom: -2px;
    left: 0;
    width: 100%;
    line-height: 0;
}

.hero__wave svg {
    width: 100%;
    height: 80px;
    fill: var(--bg);
}

/* ============================================================
   SERVICES
   ============================================================ */
.services {
    padding: 100px 0;
    background: var(--bg);
}

.services__grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(260px, 1fr));
    gap: 24px;
}

.service-card {
    background: var(--bg);
    border: 1px solid var(--border);
    border-radius: var(--radius);
    padding: 32px 28px;
    transition: all var(--transition);
}

.service-card:hover {
    transform: translateY(-6px);
    box-shadow: var(--shadow-lg);
    border-color: var(--primary);
}

.service-card__icon {
    font-size: 2.5rem;
    margin-bottom: 16px;
}

.service-card__title {
    font-size: 1.25rem;
    font-weight: 700;
    margin-bottom: 8px;
}

.service-card__desc {
    color: var(--text-light);
    font-size: 0.95rem;
    margin-bottom: 16px;
}

.service-card__features {
    list-style: none;
    display: flex;
    flex-direction: column;
    gap: 8px;
}

.service-card__features li {
    font-size: 0.9rem;
    color: var(--text-light);
    padding-left: 20px;
    position: relative;
}

.service-card__features li::before {
    content: '✓';
    position: absolute;
    left: 0;
    color: #22c55e;
    font-weight: 700;
}

/* ============================================================
   PRODUCTS
   ============================================================ */
.products {
    padding: 100px 0;
    background: var(--bg-alt);
}

.products__grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(260px, 1fr));
    gap: 24px;
}

.product-card {
    background: var(--bg);
    border-radius: var(--radius);
    overflow: hidden;
    box-shadow: var(--shadow);
    transition: all var(--transition);
}

.product-card:hover {
    transform: translateY(-6px);
    box-shadow: var(--shadow-lg);
}

.product-card__img {
    position: relative;
    aspect-ratio: 4/3;
    background: linear-gradient(135deg, #f1f5f9, #e2e8f0);
    display: flex;
    align-items: center;
    justify-content: center;
}

.product-card__placeholder {
    font-size: 3.5rem;
}

.product-card__badge {
    position: absolute;
    top: 12px;
    left: 12px;
    background: #22c55e;
    color: #fff;
    padding: 4px 12px;
    border-radius: 50px;
    font-size: 0.75rem;
    font-weight: 700;
}

.product-card__badge--hot {
    background: #ef4444;
}

.product-card__badge--new {
    background: var(--primary);
}

.product-card__body {
    padding: 20px;
}

.product-card__title {
    font-size: 1.1rem;
    font-weight: 700;
    margin-bottom: 6px;
}

.product-card__specs {
    font-size: 0.85rem;
    color: var(--text-light);
    margin-bottom: 16px;
}

.product-card__price {
    margin-bottom: 16px;
}

.product-card__price-value {
    font-size: 1.25rem;
    font-weight: 800;
    color: #ef4444;
}

.product-card__price-unit {
    font-size: 0.875rem;
    color: var(--text-light);
}

/* ============================================================
   PRICING
   ============================================================ */
.pricing {
    padding: 100px 0;
    background: var(--bg);
}

.pricing__grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 24px;
    align-items: stretch;
}

.pricing-card {
    background: var(--bg);
    border: 2px solid var(--border);
    border-radius: var(--radius);
    padding: 36px 28px;
    text-align: center;
    transition: all var(--transition);
    position: relative;
    display: flex;
    flex-direction: column;
}

.pricing-card:hover {
    border-color: var(--primary);
    box-shadow: var(--shadow-lg);
}

.pricing-card--popular {
    border-color: var(--primary);
    transform: scale(1.03);
    box-shadow: var(--shadow-lg);
}

.pricing-card--popular:hover {
    transform: scale(1.03) translateY(-6px);
}

.pricing-card__popular-badge {
    position: absolute;
    top: -14px;
    left: 50%;
    transform: translateX(-50%);
    background: var(--primary);
    color: #fff;
    padding: 6px 24px;
    border-radius: 50px;
    font-size: 0.85rem;
    font-weight: 700;
    white-space: nowrap;
}

.pricing-card__header h3 {
    font-size: 1.35rem;
    font-weight: 700;
    margin-bottom: 4px;
}

.pricing-card__header p {
    color: var(--text-light);
    font-size: 0.9rem;
}

.pricing-card__price {
    margin: 24px 0;
}

.pricing-card__amount {
    font-size: 2.5rem;
    font-weight: 800;
    color: var(--primary);
}

.pricing-card__period {
    font-size: 1rem;
    color: var(--text-light);
}

.pricing-card__features {
    list-style: none;
    text-align: left;
    display: flex;
    flex-direction: column;
    gap: 12px;
    margin-bottom: 32px;
    flex: 1;
}

.pricing-card__features li {
    font-size: 0.95rem;
    color: var(--text);
}

/* ============================================================
   WHY US
   ============================================================ */
.why-us {
    padding: 100px 0;
    background: var(--bg-alt);
}

.why-us__grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 24px;
}

.why-card {
    background: var(--bg);
    border-radius: var(--radius);
    padding: 32px 28px;
    transition: all var(--transition);
    box-shadow: var(--shadow);
}

.why-card:hover {
    transform: translateY(-4px);
    box-shadow: var(--shadow-lg);
}

.why-card__icon {
    font-size: 2.5rem;
    margin-bottom: 16px;
}

.why-card h3 {
    font-size: 1.15rem;
    font-weight: 700;
    margin-bottom: 8px;
}

.why-card p {
    color: var(--text-light);
    font-size: 0.95rem;
}

/* ============================================================
   TESTIMONIALS
   ============================================================ */
.testimonials {
    padding: 100px 0;
    background: var(--bg);
}

.testimonials__grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 24px;
}

.testimonial-card {
    background: var(--bg-alt);
    border-radius: var(--radius);
    padding: 28px;
    transition: all var(--transition);
}

.testimonial-card:hover {
    box-shadow: var(--shadow-md);
}

.testimonial-card__stars {
    font-size: 1.1rem;
    margin-bottom: 12px;
}

.testimonial-card__text {
    font-size: 0.95rem;
    color: var(--text);
    font-style: italic;
    margin-bottom: 20px;
    line-height: 1.7;
}

.testimonial-card__author {
    display: flex;
    align-items: center;
    gap: 12px;
}

.testimonial-card__avatar {
    font-size: 2.5rem;
}

.testimonial-card__author strong {
    display: block;
    font-size: 0.95rem;
}

.testimonial-card__author span {
    font-size: 0.8rem;
    color: var(--text-light);
}

/* ============================================================
   PROCESS
   ============================================================ */
.process {
    padding: 100px 0;
    background: var(--bg-alt);
}

.process__steps {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
    gap: 40px;
}

.process-step {
    text-align: center;
    position: relative;
}

.process-step__number {
    font-size: 4rem;
    font-weight: 900;
    color: var(--primary-light);
    line-height: 1;
    margin-bottom: -20px;
}

.process-step__icon {
    font-size: 2.5rem;
    margin-bottom: 16px;
    position: relative;
    z-index: 1;
}

.process-step h3 {
    font-size: 1.15rem;
    font-weight: 700;
    margin-bottom: 8px;
}

.process-step p {
    font-size: 0.9rem;
    color: var(--text-light);
}

/* ============================================================
   CONTACT
   ============================================================ */
.contact {
    padding: 100px 0;
    background: var(--bg);
}

.contact__inner {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 60px;
    align-items: start;
}

.contact__desc {
    color: var(--text-light);
    margin-bottom: 36px;
    font-size: 1.05rem;
}

.contact__items {
    display: flex;
    flex-direction: column;
    gap: 20px;
}

.contact__item {
    display: flex;
    gap: 16px;
    align-items: flex-start;
}

.contact__item-icon {
    font-size: 1.5rem;
    width: 48px;
    height: 48px;
    background: var(--primary-light);
    border-radius: var(--radius-sm);
    display: flex;
    align-items: center;
    justify-content: center;
    flex-shrink: 0;
}

.contact__item strong {
    display: block;
    font-size: 0.95rem;
    margin-bottom: 2px;
}

.contact__item p {
    color: var(--text-light);
    font-size: 0.9rem;
}

.contact__form {
    background: var(--bg);
    border: 1px solid var(--border);
    border-radius: var(--radius);
    padding: 36px;
    box-shadow: var(--shadow-lg);
}

.contact__form h3 {
    font-size: 1.35rem;
    font-weight: 700;
    margin-bottom: 24px;
    text-align: center;
}

.form-group {
    margin-bottom: 16px;
}

.form-control {
    width: 100%;
    padding: 12px 16px;
    border: 2px solid var(--border);
    border-radius: var(--radius-sm);
    font-size: 0.95rem;
    font-family: inherit;
    transition: all var(--transition);
    background: var(--bg-alt);
}

.form-control:focus {
    outline: none;
    border-color: var(--primary);
    box-shadow: 0 0 0 3px rgba(37,99,235,0.15);
    background: var(--bg);
}

textarea.form-control {
    resize: vertical;
    min-height: 120px;
}

/* ============================================================
   FOOTER
   ============================================================ */
.footer {
    background: var(--bg-dark);
    color: #cbd5e1;
    padding: 64px 0 24px;
}

.footer__grid {
    display: grid;
    grid-template-columns: 2fr 1fr 1fr 1fr;
    gap: 40px;
    margin-bottom: 48px;
}

.footer__logo {
    margin-bottom: 16px;
    color: #fff;
}

.footer__desc {
    font-size: 0.9rem;
    margin-bottom: 20px;
    line-height: 1.7;
}

.footer__socials {
    display: flex;
    gap: 12px;
}

.footer__social {
    width: 40px;
    height: 40px;
    background: rgba(255,255,255,0.1);
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 1.1rem;
    transition: all var(--transition);
}

.footer__social:hover {
    background: var(--primary);
    transform: translateY(-2px);
}

.footer__col h4 {
    color: #fff;
    font-size: 1rem;
    font-weight: 700;
    margin-bottom: 20px;
}

.footer__col ul {
    display: flex;
    flex-direction: column;
    gap: 12px;
}

.footer__col ul li a {
    font-size: 0.9rem;
    color: #94a3b8;
    transition: color var(--transition);
}

.footer__col ul li a:hover {
    color: #fff;
}

.footer__bottom {
    padding-top: 24px;
    border-top: 1px solid rgba(255,255,255,0.1);
    text-align: center;
    font-size: 0.85rem;
    color: #64748b;
}

/* ============================================================
   BACK TO TOP
   ============================================================ */
.back-to-top {
    position: fixed;
    bottom: 30px;
    right: 30px;
    width: 48px;
    height: 48px;
    background: var(--primary);
    color: #fff;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 1.2rem;
    box-shadow: var(--shadow-lg);
    opacity: 0;
    visibility: hidden;
    transition: all var(--transition);
    z-index: 999;
}

.back-to-top.show {
    opacity: 1;
    visibility: visible;
}

.back-to-top:hover {
    background: var(--primary-dark);
    transform: translateY(-3px);
}

/* ============================================================
   RESPONSIVE
   ============================================================ */
@media (max-width: 1024px) {
    .footer__grid {
        grid-template-columns: 1fr 1fr;
    }
}

@media (max-width: 768px) {
    :root {
        --header-height: 64px;
    }

    /* --- Nav mobile --- */
    .nav {
        position: fixed;
        top: 0;
        right: -100%;
        width: 280px;
        height: 100vh;
        background: var(--bg);
        padding: 80px 30px 30px;
        box-shadow: var(--shadow-lg);
        transition: all var(--transition);
        z-index: 999;
    }

    .nav.open {
        right: 0;
    }

    .nav__list {
        flex-direction: column;
        gap: 20px;
    }

    .nav__link {
        font-size: 1.1rem;
    }

    .hamburger { display: flex; }
    .header__phone { display: none; }

    /* --- Hero --- */
    .hero__inner {
        grid-template-columns: 1fr;
        text-align: center;
    }

    .hero__title { font-size: 2.25rem; }
    .hero__desc { max-width: 100%; margin: 0 auto 32px; }
    .hero__cta { justify-content: center; flex-wrap: wrap; }
    .hero__stats { justify-content: center; }
    .hero__image { display: none; }

    /* --- Section Header --- */
    .section-header__title { font-size: 1.75rem; }

    /* --- Contact --- */
    .contact__inner {
        grid-template-columns: 1fr;
    }

    .section-header__title--left { text-align: center; }
    .contact__desc { text-align: center; }

    /* --- Footer --- */
    .footer__grid {
        grid-template-columns: 1fr;
        gap: 32px;
    }

    /* --- Pricing --- */
    .pricing-card--popular {
        transform: none;
    }

    .pricing-card--popular:hover {
        transform: translateY(-6px);
    }
}

@media (max-width: 480px) {
    .hero__title { font-size: 1.75rem; }
    .hero__stats { gap: 24px; }
    .stat__number { font-size: 1.5rem; }
    .btn { padding: 10px 20px; font-size: 0.9rem; }
    .services__grid,
    .products__grid,
    .pricing__grid,
    .testimonials__grid { grid-template-columns: 1fr; }
}