/*
Theme Name: ai-vietxinchao-theme
Theme URI: https://vietxinchao.com/
Author: VietXinChao Team
Author URI: https://vietxinchao.com/
Description: Custom modern theme for VietXinChao & VLearn ecosystem with blue brand identity and English primary interface.
Version: 1.0.0
License: GNU General Public License v2 or later
Text Domain: ai-vietxinchao-theme
*/

:root {
    /* VietXinChao & VLearn Blue Brand Palette */
    --vxc-theme-primary: #0284c7;         /* Sky / Ocean Blue */
    --vxc-theme-primary-dark: #0369a1;    /* Deep Blue Hover */
    --vxc-theme-accent: #06b6d4;          /* Cyan Accent */
    --vxc-theme-dark: #0f172a;            /* Slate Dark */
    --vxc-theme-gray: #f8fafc;
    --vxc-theme-soft-blue: #f0f9ff;
    --vxc-theme-border: #e2e8f0;
    --vxc-theme-text: #1e293b;
    --vxc-theme-text-muted: #64748b;
    --vxc-theme-font: 'Be Vietnam Pro', -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif;
}

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

body {
    font-family: var(--vxc-theme-font);
    color: var(--vxc-theme-text);
    background-color: #ffffff;
    line-height: 1.6;
    -webkit-font-smoothing: antialiased;
}

a {
    color: var(--vxc-theme-primary);
    text-decoration: none;
    transition: color 0.2s;
}

a:hover {
    color: var(--vxc-theme-primary-dark);
}

.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 24px;
}

/* Header Navbar */
.site-header {
    background: rgba(255, 255, 255, 0.95);
    backdrop-filter: blur(10px);
    border-bottom: 1px solid var(--vxc-theme-border);
    position: sticky;
    top: 0;
    z-index: 999;
}

.navbar {
    display: flex;
    justify-content: space-between;
    align-items: center;
    height: 74px;
}

.brand-logo {
    display: flex;
    align-items: center;
    gap: 10px;
    font-size: 22px;
    font-weight: 800;
    color: var(--vxc-theme-primary);
    letter-spacing: -0.5px;
}

.brand-logo .brand-highlight {
    color: var(--vxc-theme-dark);
}

.nav-links {
    display: flex;
    list-style: none;
    align-items: center;
    gap: 30px;
}

.nav-links a {
    color: #334155;
    font-weight: 600;
    font-size: 14.5px;
}

.nav-links a:hover {
    color: var(--vxc-theme-primary);
}

.nav-btn-cta {
    background: linear-gradient(135deg, var(--vxc-theme-primary), var(--vxc-theme-accent));
    color: #ffffff !important;
    padding: 10px 20px;
    border-radius: 22px;
    font-size: 13.5px;
    font-weight: 700;
    box-shadow: 0 4px 14px rgba(2, 132, 199, 0.3);
    transition: all 0.2s;
}

.nav-btn-cta:hover {
    transform: translateY(-2px);
    box-shadow: 0 6px 18px rgba(2, 132, 199, 0.45);
}

/* Hero Section */
.hero-section {
    padding: 80px 0 70px;
    background: radial-gradient(circle at 80% 20%, #e0f2fe 0%, #ffffff 65%);
}

.hero-grid {
    display: grid;
    grid-template-columns: 1.15fr 0.85fr;
    gap: 50px;
    align-items: center;
}

.hero-tag {
    display: inline-flex;
    align-items: center;
    gap: 8px;
    background: #e0f2fe;
    color: var(--vxc-theme-primary-dark);
    font-size: 13px;
    font-weight: 700;
    padding: 6px 16px;
    border-radius: 20px;
    margin-bottom: 22px;
    border: 1px solid #bae6fd;
}

.hero-title {
    font-size: 46px;
    font-weight: 900;
    line-height: 1.22;
    color: #0f172a;
    margin-bottom: 20px;
    letter-spacing: -1px;
}

.hero-title span {
    background: linear-gradient(135deg, var(--vxc-theme-primary), #06b6d4);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
}

.hero-desc {
    font-size: 16.5px;
    color: var(--vxc-theme-text-muted);
    margin-bottom: 32px;
    line-height: 1.7;
}

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

.btn-primary-lg {
    background: linear-gradient(135deg, var(--vxc-theme-primary), var(--vxc-theme-accent));
    color: #ffffff;
    padding: 14px 28px;
    border-radius: 30px;
    font-weight: 700;
    font-size: 15px;
    box-shadow: 0 6px 20px rgba(2, 132, 199, 0.35);
    display: inline-flex;
    align-items: center;
    gap: 8px;
    border: none;
    cursor: pointer;
    transition: all 0.2s;
}

.btn-primary-lg:hover {
    color: #ffffff;
    transform: translateY(-2px);
    box-shadow: 0 8px 24px rgba(2, 132, 199, 0.45);
}

.btn-secondary-lg {
    background: #f1f5f9;
    color: #334155;
    padding: 14px 26px;
    border-radius: 30px;
    font-weight: 700;
    font-size: 15px;
    border: 1px solid #e2e8f0;
    transition: all 0.2s;
}

.btn-secondary-lg:hover {
    background: #e2e8f0;
    color: #0f172a;
}

/* Hero Showcase Card */
.hero-showcase-card {
    background: #ffffff;
    border-radius: 26px;
    padding: 32px;
    box-shadow: 0 25px 50px -12px rgba(2, 132, 199, 0.12);
    border: 1px solid #e0f2fe;
    text-align: center;
    position: relative;
}

.showcase-header {
    display: flex;
    align-items: center;
    gap: 16px;
    margin-bottom: 22px;
    text-align: left;
}

.showcase-avatar {
    width: 64px;
    height: 64px;
    border-radius: 50%;
    object-fit: cover;
    border: 3px solid #bae6fd;
    box-shadow: 0 4px 12px rgba(2, 132, 199, 0.15);
}

.showcase-title h4 {
    font-size: 18px;
    font-weight: 800;
    color: #0f172a;
}

.showcase-title p {
    font-size: 12.5px;
    color: #10b981;
    font-weight: 700;
    display: flex;
    align-items: center;
    gap: 5px;
}

.showcase-chat-bubble {
    background: #f8fafc;
    border-radius: 18px;
    padding: 18px;
    font-size: 14px;
    color: #334155;
    text-align: left;
    margin-bottom: 24px;
    border-left: 4px solid var(--vxc-theme-primary);
    line-height: 1.6;
}

/* Features Section */
.features-section {
    padding: 80px 0;
    background: #f8fafc;
    border-top: 1px solid var(--vxc-theme-border);
}

.section-header {
    text-align: center;
    max-width: 680px;
    margin: 0 auto 55px;
}

.section-header h2 {
    font-size: 34px;
    font-weight: 800;
    margin-bottom: 14px;
    color: #0f172a;
    letter-spacing: -0.5px;
}

.section-header p {
    font-size: 16px;
    color: var(--vxc-theme-text-muted);
}

.features-grid {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 28px;
}

.feature-card {
    background: #ffffff;
    border-radius: 20px;
    padding: 32px 28px;
    box-shadow: 0 4px 20px rgba(0, 0, 0, 0.03);
    border: 1px solid #e2e8f0;
    transition: transform 0.2s, box-shadow 0.2s;
}

.feature-card:hover {
    transform: translateY(-4px);
    box-shadow: 0 12px 28px rgba(2, 132, 199, 0.08);
}

.feature-icon {
    font-size: 36px;
    margin-bottom: 18px;
}

.feature-card h3 {
    font-size: 19px;
    font-weight: 800;
    margin-bottom: 12px;
    color: #0f172a;
}

.feature-card p {
    font-size: 14px;
    color: var(--vxc-theme-text-muted);
    line-height: 1.6;
}

/* Footer */
.site-footer {
    background: var(--vxc-theme-dark);
    color: #94a3b8;
    padding: 50px 0 30px;
    font-size: 13.5px;
}

.footer-content {
    display: flex;
    justify-content: space-between;
    align-items: center;
    border-bottom: 1px solid rgba(255, 255, 255, 0.1);
    padding-bottom: 30px;
    margin-bottom: 25px;
}

.footer-brand {
    font-size: 20px;
    font-weight: 800;
    color: #ffffff;
}

.footer-links {
    display: flex;
    gap: 28px;
    list-style: none;
}

.footer-links a {
    color: #cbd5e1;
    font-weight: 500;
}
.footer-links a:hover {
    color: #38bdf8;
}

.footer-bottom {
    text-align: center;
    font-size: 12.5px;
    color: #64748b;
}

@media (max-width: 860px) {
    .hero-grid { grid-template-columns: 1fr; }
    .features-grid { grid-template-columns: 1fr; }
    .nav-links { display: none; }
    .hero-title { font-size: 32px; }
}