/* Reset & Variables */
:root {
    --bg-color: #0f172a;
    /* Nền tối xanh đen */
    --card-bg: #1e293b;
    /* Nền card */
    --text-main: #f8fafc;
    /* Chữ trắng sáng */
    --text-sub: #94a3b8;
    /* Chữ xám */
    --accent: #38bdf8;
    /* Màu nhấn xanh dương */
    --gradient: linear-gradient(135deg, #38bdf8 0%, #818cf8 100%);
}

* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

body {
    font-family: system-ui, -apple-system, sans-serif;
    /* Font hệ thống cho tốc độ nhanh nhất */
    background-color: var(--bg-color);
    color: var(--text-main);
    line-height: 1.6;
}

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

/* Layout */
.container {
    max-width: 1100px;
    margin: 0 auto;
    padding: 0 20px;
}

/* Navbar */
header {
    padding: 20px 0;
    border-bottom: 1px solid rgba(255, 255, 255, 0.1);
    position: sticky;
    top: 0;
    background: rgba(15, 23, 42, 0.9);
    backdrop-filter: blur(10px);
    z-index: 100;
}

.navbar {
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.logo {
    font-size: 1.5rem;
    font-weight: 800;
    background: var(--gradient);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
}

.nav-links {
    display: flex;
    gap: 30px;
}

.nav-links a {
    color: var(--text-sub);
    transition: color 0.3s;
}

.nav-links a:hover,
.nav-links a.active {
    color: var(--text-main);
}

/* Hero Section */
.hero {
    padding: 100px 0;
    text-align: center;
}

.hero h1 {
    font-size: 3.5rem;
    font-weight: 800;
    margin-bottom: 20px;
    background: var(--gradient);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
}

.hero p {
    font-size: 1.25rem;
    color: var(--text-sub);
    max-width: 600px;
    margin: 0 auto 40px;
}

.btn {
    display: inline-block;
    padding: 12px 30px;
    background: var(--gradient);
    color: #0f172a;
    font-weight: 700;
    border-radius: 50px;
    transition: transform 0.3s, box-shadow 0.3s;
}

.btn:hover {
    transform: translateY(-3px);
    box-shadow: 0 10px 20px rgba(56, 189, 248, 0.3);
}

/* Features / Cards */
.features {
    padding: 80px 0;
}

.section-title {
    text-align: center;
    font-size: 2rem;
    margin-bottom: 50px;
}

.grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: 30px;
}

.card {
    background: var(--card-bg);
    padding: 30px;
    border-radius: 15px;
    border: 1px solid rgba(255, 255, 255, 0.05);
    transition: transform 0.3s;
}

.card:hover {
    transform: translateY(-5px);
    border-color: var(--accent);
}

.card-icon {
    font-size: 2rem;
    margin-bottom: 15px;
}

.card h3 {
    margin-bottom: 10px;
    font-size: 1.25rem;
}

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

/* Footer */
footer {
    text-align: center;
    padding: 40px 0;
    border-top: 1px solid rgba(255, 255, 255, 0.1);
    color: var(--text-sub);
    margin-top: 50px;
}

/* Responsive */
@media (max-width: 768px) {
    .hero h1 {
        font-size: 2.5rem;
    }

    .nav-links {
        gap: 15px;
    }
}

/* --- Section 3: Process (Quy trình) --- */
.process {
    padding: 80px 0;
    background-color: #162032;
}

/* Nền hơi khác để tạo nhịp điệu */
.process-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 40px;
}

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

.step-number {
    font-size: 4rem;
    font-weight: 900;
    line-height: 1;
    background: var(--gradient);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    opacity: 0.8;
    margin-bottom: 15px;
}

.process-step h3 {
    font-size: 1.25rem;
    margin-bottom: 10px;
}

.process-step p {
    color: var(--text-sub);
    font-size: 0.95rem;
}

/* --- Section 4: Stats (Thống kê) --- */
.stats {
    padding: 80px 0;
    text-align: center;
}

.stats-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(150px, 1fr));
    gap: 30px;
    margin-bottom: 60px;
}

.stat-item h2 {
    font-size: 3rem;
    font-weight: 800;
    margin-bottom: 5px;
    background: var(--gradient);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
}

.stat-item p {
    color: var(--text-sub);
    text-transform: uppercase;
    font-size: 0.85rem;
    letter-spacing: 1px;
}

/* --- CTA Banner (Lời kêu gọi hành động) --- */
.cta-banner {
    background: var(--gradient);
    padding: 60px 40px;
    border-radius: 20px;
    text-align: center;
    margin-bottom: 80px;
    position: relative;
    overflow: hidden;
}

.cta-banner::before {
    content: '';
    position: absolute;
    top: -50%;
    left: -50%;
    width: 200%;
    height: 200%;
    background: radial-gradient(circle, rgba(255, 255, 255, 0.1) 0%, transparent 70%);
}

.cta-banner h2 {
    font-size: 2.2rem;
    color: #0f172a;
    margin-bottom: 15px;
    position: relative;
    z-index: 1;
}

.cta-banner p {
    color: rgba(15, 23, 42, 0.8);
    font-size: 1.1rem;
    margin-bottom: 30px;
    position: relative;
    z-index: 1;
}

.btn-dark {
    display: inline-block;
    padding: 14px 35px;
    background: #0f172a;
    color: #f8fafc;
    font-weight: 700;
    border-radius: 50px;
    transition: transform 0.3s, box-shadow 0.3s;
    position: relative;
    z-index: 1;
}

.btn-dark:hover {
    transform: translateY(-3px);
    box-shadow: 0 10px 20px rgba(0, 0, 0, 0.3);
}

/* =========================================
   TRANG ABOUT - CÁC SECTION MỚI
   ========================================= */

/* 1. AI Pillars (3 Trụ cột) */
.ai-pillars {
    padding: 80px 0;
}

.pillar-card {
    background: linear-gradient(145deg, #1e293b, #0f172a);
    padding: 40px 30px;
    border-radius: 20px;
    text-align: center;
    border: 1px solid rgba(56, 189, 248, 0.1);
    transition: all 0.4s ease;
    position: relative;
    overflow: hidden;
}

.pillar-card::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 4px;
    background: var(--gradient);
    transform: scaleX(0);
    transition: transform 0.4s;
}

.pillar-card:hover {
    transform: translateY(-10px);
    border-color: var(--accent);
}

.pillar-card:hover::before {
    transform: scaleX(1);
}

.pillar-icon {
    font-size: 3rem;
    margin-bottom: 20px;
    display: block;
}

.pillar-card h3 {
    font-size: 1.5rem;
    margin-bottom: 15px;
    color: var(--text-main);
}

.pillar-card p {
    color: var(--text-sub);
    line-height: 1.7;
}

/* 2. Tech Spotlight (Trình bày so le Trái - Phải) */
.tech-spotlight {
    padding: 80px 0;
    background-color: #162032;
}

.spotlight-row {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 60px;
    align-items: center;
    margin-bottom: 80px;
}

.spotlight-row:last-child {
    margin-bottom: 0;
}

.spotlight-row.reverse {
    direction: rtl;
}

/* Đảo ngược cột */
.spotlight-row.reverse>* {
    direction: ltr;
}

/* Giữ text không bị ngược */

.spotlight-visual {
    background: rgba(56, 189, 248, 0.05);
    border: 1px dashed rgba(56, 189, 248, 0.3);
    border-radius: 20px;
    padding: 60px;
    text-align: center;
    font-size: 5rem;
    display: flex;
    align-items: center;
    justify-content: center;
    min-height: 250px;
}

.spotlight-content h3 {
    font-size: 2rem;
    margin-bottom: 20px;
    background: var(--gradient);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
}

.spotlight-content p {
    color: var(--text-sub);
    font-size: 1.05rem;
    line-height: 1.8;
    margin-bottom: 15px;
}

.tech-tag {
    display: inline-block;
    background: rgba(56, 189, 248, 0.1);
    color: var(--accent);
    padding: 5px 12px;
    border-radius: 20px;
    font-size: 0.8rem;
    margin-right: 8px;
    margin-bottom: 8px;
}

/* 3. Tech Ecosystem (Lưới từ khóa dày đặc) */
.tech-ecosystem {
    padding: 80px 0;
    text-align: center;
}

.ecosystem-grid {
    display: flex;
    flex-wrap: wrap;
    justify-content: center;
    gap: 15px;
    margin-top: 40px;
}

.eco-tag {
    background: var(--card-bg);
    border: 1px solid rgba(255, 255, 255, 0.05);
    padding: 12px 24px;
    border-radius: 50px;
    font-size: 0.95rem;
    font-weight: 500;
    transition: all 0.3s;
    cursor: default;
}

.eco-tag:hover {
    background: var(--gradient);
    color: #0f172a;
    transform: scale(1.05);
    border-color: transparent;
    font-weight: 700;
}

/* Responsive cho About */
@media (max-width: 768px) {

    .spotlight-row,
    .spotlight-row.reverse {
        grid-template-columns: 1fr;
        gap: 30px;
        direction: ltr;
    }

    .spotlight-visual {
        padding: 40px;
        font-size: 3rem;
        min-height: 150px;
    }
}

/* =========================================
   TRANG HỢP TÁC & ĐẦU TƯ (PREMIUM ELEGANT)
   ========================================= */
:root {
    --gold-accent: #d4b872;
    /* Màu vàng champagne sang trọng */
    --gold-light: #f3e5ab;
    --gold-bg: rgba(212, 184, 114, 0.05);
}

/* Link đặc biệt trên navbar */
.nav-premium {
    color: var(--gold-accent) !important;
    font-weight: 600;
    position: relative;
}

.nav-premium::after {
    content: '';
    position: absolute;
    bottom: -5px;
    left: 0;
    width: 100%;
    height: 1px;
    background: var(--gold-accent);
    transform: scaleX(0);
    transition: transform 0.3s;
}

.nav-premium:hover::after,
.nav-premium.active::after {
    transform: scaleX(1);
}

/* Hero trang hợp tác */
.invest-hero {
    padding: 120px 0 80px;
    text-align: center;
    border-bottom: 1px solid rgba(212, 184, 114, 0.2);
}

.invest-hero h1 {
    font-size: 3rem;
    font-weight: 300;
    letter-spacing: 2px;
    margin-bottom: 20px;
    color: var(--gold-light);
    text-transform: uppercase;
}

.invest-hero p {
    font-size: 1.15rem;
    color: var(--text-sub);
    max-width: 700px;
    margin: 0 auto;
    line-height: 1.8;
    font-weight: 300;
}

/* Value Proposition (Lợi thế) */
.invest-value {
    padding: 100px 0;
}

.value-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 40px;
}

.value-card {
    padding: 40px;
    border: 1px solid rgba(255, 255, 255, 0.05);
    border-radius: 2px;
    /* Góc vuông tạo cảm giác nghiêm túc */
    background: linear-gradient(180deg, rgba(255, 255, 255, 0.02) 0%, transparent 100%);
    transition: all 0.4s ease;
}

.value-card:hover {
    border-color: var(--gold-accent);
    background: var(--gold-bg);
}

.value-card h3 {
    font-size: 1.2rem;
    color: var(--gold-accent);
    margin-bottom: 15px;
    font-weight: 500;
    letter-spacing: 1px;
}

.value-card p {
    color: var(--text-sub);
    line-height: 1.8;
    font-size: 0.95rem;
}

/* Roadmap / Timeline (Lộ trình) */
.invest-roadmap {
    padding: 100px 0;
    background-color: #0b1120;
}

.timeline {
    max-width: 800px;
    margin: 60px auto 0;
    position: relative;
}

.timeline::before {
    content: '';
    position: absolute;
    left: 20px;
    top: 0;
    bottom: 0;
    width: 1px;
    background: linear-gradient(to bottom, transparent, var(--gold-accent), transparent);
}

.timeline-item {
    padding-left: 60px;
    margin-bottom: 50px;
    position: relative;
}

.timeline-item::before {
    content: '';
    position: absolute;
    left: 15px;
    top: 5px;
    width: 11px;
    height: 11px;
    border-radius: 50%;
    background: var(--bg-color);
    border: 2px solid var(--gold-accent);
}

.timeline-item h4 {
    color: var(--gold-light);
    font-size: 1.1rem;
    font-weight: 600;
    margin-bottom: 8px;
    letter-spacing: 1px;
}

.timeline-item p {
    color: var(--text-sub);
    font-size: 0.95rem;
    line-height: 1.7;
}

/* Partnership Models (Mô hình hợp tác) */
.invest-models {
    padding: 100px 0;
    text-align: center;
}

.models-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: 30px;
    margin-top: 60px;
}

.model-card {
    padding: 50px 30px;
    border: 1px solid rgba(212, 184, 114, 0.2);
    border-radius: 4px;
    background: rgba(212, 184, 114, 0.02);
    transition: all 0.4s;
}

.model-card:hover {
    transform: translateY(-5px);
    border-color: var(--gold-accent);
    box-shadow: 0 20px 40px rgba(0, 0, 0, 0.3);
}

.model-card h3 {
    font-size: 1.3rem;
    color: var(--text-main);
    margin-bottom: 10px;
    font-weight: 600;
}

.model-card .model-tag {
    color: var(--gold-accent);
    font-size: 0.85rem;
    text-transform: uppercase;
    letter-spacing: 2px;
    margin-bottom: 20px;
    display: block;
}

.model-card p {
    color: var(--text-sub);
    font-size: 0.95rem;
    line-height: 1.7;
    margin-bottom: 30px;
}

.btn-gold {
    display: inline-block;
    padding: 12px 30px;
    border: 1px solid var(--gold-accent);
    color: var(--gold-accent);
    font-size: 0.9rem;
    letter-spacing: 1px;
    transition: all 0.3s;
    text-transform: uppercase;
}

.btn-gold:hover {
    background: var(--gold-accent);
    color: #0f172a;
    font-weight: 600;
}

/* CTA cuối trang */
.invest-cta {
    padding: 100px 0;
    text-align: center;
    border-top: 1px solid rgba(212, 184, 114, 0.2);
}

.invest-cta h2 {
    font-size: 2rem;
    color: var(--gold-light);
    font-weight: 300;
    letter-spacing: 1px;
    margin-bottom: 20px;
}

.invest-cta p {
    color: var(--text-sub);
    margin-bottom: 40px;
}

/* Responsive */
@media (max-width: 768px) {
    .invest-hero h1 {
        font-size: 2rem;
        letter-spacing: 1px;
    }

    .timeline::before {
        left: 10px;
    }

    .timeline-item {
        padding-left: 40px;
    }

    .timeline-item::before {
        left: 5px;
    }
}

/* =========================================
   1. CẬP NHẬT NAVBAR (HIỆU ỨNG SÁNG)
   ========================================= */
.nav-links {
    display: flex;
    gap: 30px;
}

.nav-links a {
    color: var(--text-sub);
    transition: all 0.3s;
    position: relative;
    padding-bottom: 5px;
}

/* Gạch chân màu xanh cho link thường */
.nav-links a:not(.nav-premium)::after {
    content: '';
    position: absolute;
    bottom: 0;
    left: 0;
    width: 100%;
    height: 2px;
    background: var(--accent);
    transform: scaleX(0);
    transition: transform 0.3s;
}

.nav-links a:not(.nav-premium):hover::after,
.nav-links a:not(.nav-premium).active::after {
    transform: scaleX(1);
}

.nav-links a:hover {
    color: var(--text-main);
}

.nav-links a.active {
    color: var(--text-main);
    font-weight: 600;
}

/* Gạch chân màu vàng cho link Premium (Hợp tác) */
.nav-premium {
    color: var(--gold-accent) !important;
}

.nav-premium::after {
    content: '';
    position: absolute;
    bottom: 0;
    left: 0;
    width: 100%;
    height: 2px;
    background: var(--gold-accent);
    transform: scaleX(0);
    transition: transform 0.3s;
}

.nav-premium:hover::after,
.nav-premium.active::after {
    transform: scaleX(1);
}

.nav-premium.active {
    color: var(--gold-light) !important;
    font-weight: 600;
}


/* =========================================
   2. FOOTER LIÊN HỆ MỚI (THANH LỊCH)
   ========================================= */
footer {
    background-color: #0b1120;
    /* Nền tối hơn body một chút */
    padding: 60px 0 30px;
    border-top: 1px solid rgba(255, 255, 255, 0.05);
    margin-top: 0;
}

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

.footer-brand .logo {
    font-size: 1.8rem;
    margin-bottom: 15px;
    display: inline-block;
}

.footer-brand p {
    color: var(--text-sub);
    max-width: 350px;
    line-height: 1.7;
}

.footer-contact h4 {
    color: var(--text-main);
    font-size: 1rem;
    margin-bottom: 20px;
    text-transform: uppercase;
    letter-spacing: 1px;
}

.contact-item {
    display: flex;
    align-items: center;
    gap: 12px;
    margin-bottom: 15px;
    color: var(--text-sub);
    transition: color 0.3s;
    text-decoration: none;
}

.contact-item:hover {
    color: var(--accent);
}

.contact-item.premium:hover {
    color: var(--gold-accent);
}

.contact-item svg {
    width: 20px;
    height: 20px;
    fill: currentColor;
    flex-shrink: 0;
}

.footer-bottom {
    text-align: center;
    padding-top: 30px;
    border-top: 1px solid rgba(255, 255, 255, 0.05);
    color: var(--text-sub);
    font-size: 0.85rem;
}

/* Responsive Footer */
@media (max-width: 768px) {
    .footer-content {
        grid-template-columns: 1fr;
        gap: 30px;
    }
}