/* ==========================================================================
   DESIGN SYSTEM & CSS VARIABLES
   ========================================================================== */
:root {
    /* Color Palette */
    --bg-dark: #0a0d14;
    --bg-card: #121824;
    --bg-card-alt: #182030;
    --bg-card-hover: #1e283d;
    --border-color: rgba(255, 255, 255, 0.08);
    --border-glow: rgba(99, 102, 241, 0.2);

    /* Text Colors (WCAG AA Compliant) */
    --text-main: #f1f5f9;
    --text-muted: #94a3b8;
    --text-dim: #94a3b8;
    --text-subtext: #cbd5e1;

    /* Accents & Status */
    --primary: #6366f1;
    --primary-hover: #4f46e5;
    --primary-glow: rgba(99, 102, 241, 0.3);
    
    --danger: #ef4444;
    --danger-glow: rgba(239, 68, 68, 0.2);
    
    --warning: #f59e0b;
    --warning-bg: rgba(245, 158, 11, 0.1);
    
    --success: #10b981;
    --success-bg: rgba(16, 185, 129, 0.1);

    /* Typography */
    --font-sans: 'Inter', system-ui, -apple-system, 'Segoe UI', Roboto, sans-serif;
    --font-mono: 'IBM Plex Mono', ui-monospace, 'Cascadia Code', monospace;

    /* Spacing & Layout */
    --radius-sm: 6px;
    --radius-md: 12px;
    --radius-lg: 18px;
    --transition: all 0.25s ease;
}

/* ==========================================================================
   ACCESSIBILITY & RESET
   ========================================================================== */
* {
    box-sizing: border-box;
    margin: 0;
    padding: 0;
}

html {
    scroll-behavior: smooth;
    font-size: 16px;
}

/* Scroll Offset for Fixed/Sticky Navigation */
#noi-dau, #san-pham, #tien-do, #faq, #waitlist {
    scroll-margin-top: 120px;
}

body {
    background-color: var(--bg-dark);
    color: var(--text-main);
    font-family: var(--font-sans);
    line-height: 1.6;
    -webkit-font-smoothing: antialiased;
    overflow-x: hidden;
}

/* Accessible Focus Visible Outline */
:focus-visible {
    outline: 2px solid var(--primary);
    outline-offset: 2px;
}

/* Skip-to-content link */
.skip-link {
    position: absolute;
    top: -100px;
    left: 12px;
    background: var(--primary);
    color: #ffffff;
    padding: 10px 18px;
    border-radius: var(--radius-sm);
    z-index: 1000;
    font-weight: 700;
    text-decoration: none;
    transition: top 0.2s ease;
}

.skip-link:focus {
    top: 12px;
}

.container {
    width: 100%;
    max-width: 1140px;
    margin: 0 auto;
    padding: 0 20px;
}

.max-w-700 { max-width: 700px; }
.max-w-800 { max-width: 800px; }

a {
    color: var(--primary);
    text-decoration: none;
    transition: var(--transition);
}

a:hover {
    color: #818cf8;
}

.inline-code {
    background: rgba(255, 255, 255, 0.08);
    border: 1px solid var(--border-color);
    border-radius: 4px;
    padding: 2px 6px;
    font-family: var(--font-mono);
    font-size: .875em;
    color: #e2e8f0;
}

/* ==========================================================================
   TRANSPARENCY BANNER
   ========================================================================== */
.transparency-banner {
    background: #1e1b4b;
    border-bottom: 1px solid rgba(99, 102, 241, 0.3);
    padding: 12px 0;
    font-size: 0.9rem;
}

.banner-content {
    display: flex;
    align-items: center;
    gap: 12px;
    justify-content: center;
    text-align: center;
    flex-wrap: wrap;
}

.banner-content p {
    color: #e0e7ff;
}

/* ==========================================================================
   BADGES & BUTTONS
   ========================================================================== */
.badge {
    display: inline-block;
    padding: 4px 12px;
    border-radius: 99px;
    font-size: 0.78rem;
    font-weight: 600;
    text-transform: uppercase;
    letter-spacing: 0.5px;
}

.badge-warning {
    background: var(--warning-bg);
    color: #fbbf24;
    border: 1px solid rgba(245, 158, 11, 0.3);
}

.badge-neutral {
    background: rgba(255, 255, 255, 0.06);
    color: var(--text-muted);
    border: 1px solid var(--border-color);
}

.btn {
    display: inline-flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    padding: 14px 28px;
    border-radius: var(--radius-md);
    font-weight: 700;
    font-size: 1.05rem;
    cursor: pointer;
    border: none;
    transition: var(--transition);
    text-align: center;
    text-decoration: none;
}

.btn-primary {
    background: linear-gradient(135deg, #6366f1 0%, #4f46e5 100%);
    color: #ffffff;
    box-shadow: 0 10px 25px -5px var(--primary-glow);
}

.btn-primary:hover {
    transform: translateY(-2px);
    box-shadow: 0 15px 30px -5px rgba(99, 102, 241, 0.5);
    color: #ffffff;
}

.btn-primary.btn-lg {
    display: inline-flex;
    flex-direction: column;
    gap: 4px;
    align-items: center;
    justify-content: center;
    padding: 16px 32px;
    font-size: 1.1rem;
}

.btn-subtext {
    font-size: 12px;
    font-weight: 500;
    color: #e0e7ff;
    opacity: 0.85;
    margin-top: 0;
}

.btn-outline {
    background: transparent;
    border: 1px solid var(--border-color);
    color: var(--text-main);
    padding: 8px 16px;
    font-size: 0.88rem;
}

.btn-outline:hover {
    border-color: var(--primary);
    background: rgba(99, 102, 241, 0.1);
}

.btn-block {
    width: 100%;
}

.btn-sm {
    padding: 8px 16px;
    font-size: 0.85rem;
}

/* ==========================================================================
   HEADER & NAV
   ========================================================================== */
.site-header {
    padding: 18px 0;
    border-bottom: 1px solid var(--border-color);
    position: sticky;
    top: 0;
    background: rgba(10, 13, 20, 0.88);
    backdrop-filter: blur(12px);
    z-index: 100;
}

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

.logo {
    display: flex;
    align-items: center;
    gap: 8px;
    font-size: 1.15rem;
}

.nav-links {
    display: flex;
    align-items: center;
    gap: 24px;
}

.nav-links a {
    color: var(--text-muted);
    font-size: 0.9rem;
    font-weight: 600;
}

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

/* Hamburger Button */
.mobile-menu-btn {
    display: none;
    background: transparent;
    border: 1px solid var(--border-color);
    border-radius: var(--radius-sm);
    width: 40px;
    height: 40px;
    padding: 9px;
    cursor: pointer;
    flex-direction: column;
    justify-content: space-between;
    z-index: 102;
}

.hamburger-bar {
    display: block;
    width: 100%;
    height: 2px;
    background-color: var(--text-main);
    transition: var(--transition);
    border-radius: 2px;
}

.mobile-menu-btn.is-active .hamburger-bar:nth-child(1) {
    transform: translateY(7px) rotate(45deg);
}
.mobile-menu-btn.is-active .hamburger-bar:nth-child(2) {
    opacity: 0;
}
.mobile-menu-btn.is-active .hamburger-bar:nth-child(3) {
    transform: translateY(-7px) rotate(-45deg);
}

.mobile-nav {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100vh;
    background: rgba(10, 13, 20, 0.98);
    backdrop-filter: blur(16px);
    z-index: 99;
    display: flex;
    align-items: center;
    justify-content: center;
    transform: translateY(-100%);
    transition: transform 0.3s cubic-bezier(0.4, 0, 0.2, 1);
    opacity: 0;
    pointer-events: none;
}

.mobile-nav.is-open {
    transform: translateY(0);
    opacity: 1;
    pointer-events: auto;
}

.mobile-nav-links {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 24px;
    width: 80%;
    max-width: 320px;
}

.mobile-nav-links a {
    font-size: 1.25rem;
    font-weight: 700;
    color: var(--text-main);
}

body.menu-open {
    overflow: hidden;
}

/* ==========================================================================
   HERO SECTION
   ========================================================================== */
.hero-section {
    padding: 70px 0 50px;
    text-align: center;
    position: relative;
}

.hero-badge-group {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 12px;
    margin-bottom: 24px;
    flex-wrap: wrap;
}

.tools-tag {
    font-size: 0.85rem;
    color: #c7d2fe;
    background: rgba(99, 102, 241, 0.1);
    padding: 4px 12px;
    border-radius: 99px;
    border: 1px solid rgba(99, 102, 241, 0.2);
}

.hero-title {
    font-size: 2.8rem;
    font-weight: 800;
    line-height: 1.2;
    margin-bottom: 20px;
    letter-spacing: -0.5px;
}

.text-gradient-danger {
    background: linear-gradient(135deg, #f87171 0%, #ef4444 100%);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
}

.hero-subtitle {
    font-size: 1.2rem;
    color: var(--text-muted);
    max-width: 780px;
    margin: 0 auto 32px;
    line-height: 1.6;
}

.hero-actions {
    margin-bottom: 16px;
}

.social-proof {
    display: inline-flex;
    align-items: center;
    gap: 6px;
    background: rgba(245, 158, 11, 0.12);
    border: 1px solid rgba(245, 158, 11, 0.25);
    color: #fef08a;
    padding: 6px 16px;
    border-radius: 99px;
    font-size: 0.88rem;
    margin-bottom: 32px;
    font-weight: 500;
}

.hero-guarantee {
    display: flex;
    justify-content: center;
    gap: 24px;
    font-size: 0.9rem;
    color: var(--text-muted);
    margin-bottom: 48px;
    flex-wrap: wrap;
}

.check-icon {
    color: var(--success);
    font-weight: bold;
}

/* ==========================================================================
   CODE PREVIEW CARD
   ========================================================================== */
.code-preview-card {
    background: #0f172a;
    border: 1px solid var(--border-color);
    border-radius: var(--radius-md);
    max-width: 840px;
    margin: 0 auto;
    text-align: left;
    box-shadow: 0 20px 50px rgba(0,0,0,0.5);
    overflow: hidden;
}

.code-header {
    background: #1e293b;
    padding: 12px 16px;
    display: flex;
    align-items: center;
    gap: 12px;
    border-bottom: 1px solid var(--border-color);
}

.dots {
    display: flex;
    gap: 6px;
}

.dot {
    width: 10px;
    height: 10px;
    border-radius: 50%;
}

.dot.red { background: #ef4444; }
.dot.yellow { background: #f59e0b; }
.dot.green { background: #10b981; }

.file-name {
    font-family: var(--font-mono);
    font-size: 0.8rem;
    color: var(--text-muted);
}

.code-body {
    padding: 20px;
    font-family: var(--font-mono);
    font-size: 13px;
    line-height: 1.75;
    tab-size: 2;
    -moz-tab-size: 2;
    color: #e2e8f0;
    overflow-x: auto;
    -webkit-font-smoothing: antialiased;
}

.code-comment { color: #64748b; font-style: italic; }
.code-keyword { color: #f43f5e; font-weight: 600; }

/* ==========================================================================
   SECTIONS GENERAL
   ========================================================================== */
.section-padding {
    padding: 90px 0;
}

.section-alt {
    background: #0d111a;
    border-top: 1px solid var(--border-color);
    border-bottom: 1px solid var(--border-color);
}

.section-header {
    margin-bottom: 50px;
}

.section-tag {
    color: var(--primary);
    font-size: 0.85rem;
    font-weight: 700;
    text-transform: uppercase;
    letter-spacing: 1px;
    display: block;
    margin-bottom: 8px;
}

.section-title {
    font-size: 2.1rem;
    font-weight: 800;
    margin-bottom: 14px;
    line-height: 1.3;
}

.section-desc {
    color: var(--text-muted);
    font-size: 1.1rem;
    max-width: 720px;
    margin: 0 auto;
}

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

/* ==========================================================================
   SECTION 1: 7 PAIN POINTS GRID
   ========================================================================== */
.pain-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 24px;
}

.pain-card {
    background: var(--bg-card);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-md);
    padding: 28px;
    position: relative;
    transition: var(--transition);
}

.pain-card:hover {
    transform: translateY(-4px);
    border-color: var(--danger-glow);
    box-shadow: 0 10px 30px var(--danger-glow);
}

.pain-card-wide {
    grid-column: 1 / -1;
    background: linear-gradient(135deg, rgba(239, 68, 68, 0.05) 0%, var(--bg-card) 100%);
    border-color: rgba(239, 68, 68, 0.2);
}

.pain-number {
    font-family: var(--font-mono);
    font-size: 1.5rem;
    font-weight: 800;
    color: #ef4444;
    opacity: 0.85;
    margin-bottom: 12px;
}

.pain-title {
    font-size: 1.2rem;
    font-weight: 700;
    margin-bottom: 10px;
    color: var(--text-main);
}

.pain-desc {
    color: var(--text-muted);
    font-size: 0.95rem;
    line-height: 1.6;
}

/* ==========================================================================
   SECTION 2: TRUTH BOX
   ========================================================================== */
.truth-box {
    background: linear-gradient(135deg, rgba(99, 102, 241, 0.1) 0%, rgba(15, 23, 42, 0.6) 100%);
    border: 1px solid var(--border-glow);
    border-radius: var(--radius-lg);
    padding: 48px;
    text-align: center;
    max-width: 900px;
    margin: 0 auto;
}

.truth-badge {
    display: inline-block;
    background: var(--primary);
    color: #ffffff;
    font-size: 0.8rem;
    font-weight: 700;
    padding: 4px 12px;
    border-radius: 99px;
    margin-bottom: 20px;
}

.truth-box h2 {
    font-size: 1.8rem;
    font-weight: 800;
    margin-bottom: 20px;
    line-height: 1.4;
}

.truth-box p {
    color: var(--text-muted);
    font-size: 1.1rem;
    margin-bottom: 16px;
    line-height: 1.7;
}

.truth-box p:last-child {
    margin-bottom: 0;
    color: var(--text-main);
    font-weight: 600;
}

/* ==========================================================================
   SECTION 3: 6 PARTS GRID
   ========================================================================== */
.parts-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(340px, 1fr));
    gap: 24px;
}

.part-card {
    background: var(--bg-card);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-md);
    padding: 30px;
    transition: var(--transition);
}

.part-card:hover {
    border-color: rgba(99, 102, 241, 0.3);
    transform: translateY(-3px);
}

.part-core {
    grid-column: 1 / -1;
    background: linear-gradient(135deg, #1e1b4b 0%, var(--bg-card) 100%);
    border: 1px solid rgba(99, 102, 241, 0.4);
}

.part-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 16px;
}

.part-tag {
    font-size: 0.75rem;
    font-weight: 700;
    color: #818cf8;
    background: rgba(99, 102, 241, 0.15);
    padding: 3px 10px;
    border-radius: 99px;
}

.part-icon {
    font-size: 1.5rem;
}

.part-card h3 {
    font-size: 1.3rem;
    font-weight: 700;
    margin-bottom: 6px;
}

.part-subtext {
    font-size: 0.88rem;
    color: #c7d2fe;
    margin-bottom: 14px;
}

.part-detail {
    color: var(--text-muted);
    font-size: 0.95rem;
    line-height: 1.6;
}

/* ==========================================================================
   SECTION 4: TIMELINE STEPPER
   ========================================================================== */
.timeline-container {
    max-width: 800px;
    margin: 0 auto;
}

.timeline-stepper {
    position: relative;
    padding-left: 36px;
}

.timeline-stepper::before {
    content: '';
    position: absolute;
    left: 15px;
    top: 10px;
    bottom: 10px;
    width: 2px;
    background: var(--border-color);
}

.step {
    position: relative;
    margin-bottom: 36px;
}

.step:last-child {
    margin-bottom: 0;
}

.step-icon {
    position: absolute;
    left: -36px;
    top: 0;
    width: 32px;
    height: 32px;
    border-radius: 50%;
    background: var(--bg-card);
    border: 2px solid var(--border-color);
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 0.85rem;
    font-weight: bold;
    color: var(--text-muted);
}

.step.completed .step-icon {
    background: var(--success);
    border-color: var(--success);
    color: #ffffff;
}

.step.active .step-icon {
    background: var(--warning);
    border-color: var(--warning);
    color: #000000;
}

.step-status {
    font-size: 0.75rem;
    font-weight: 700;
    color: #fbbf24;
    letter-spacing: 0.5px;
    margin-bottom: 4px;
}

.step-content h4 {
    font-size: 1.15rem;
    font-weight: 700;
    margin-bottom: 6px;
}

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

/* ==========================================================================
   SECTION 5: WAITLIST FORM & PRICING
   ========================================================================== */
.pricing-card {
    background: var(--bg-card);
    border: 1px solid var(--border-glow);
    border-radius: var(--radius-lg);
    padding: 44px;
    box-shadow: 0 25px 60px rgba(0,0,0,0.6);
}

.pricing-badge {
    display: inline-block;
    background: var(--warning-bg);
    color: #fbbf24;
    font-weight: 700;
    font-size: 0.8rem;
    padding: 4px 14px;
    border-radius: 99px;
    margin-bottom: 12px;
    border: 1px solid rgba(245, 158, 11, 0.3);
}

.pricing-title {
    font-size: 2rem;
    font-weight: 800;
    margin-bottom: 20px;
}

.price-box {
    background: var(--bg-card-alt);
    padding: 20px;
    border-radius: var(--radius-md);
    margin-bottom: 24px;
    border: 1px solid var(--border-color);
}

.price-old {
    color: #cbd5e1;
    font-size: 0.95rem;
}

.price-old span {
    text-decoration: line-through;
}

.price-current {
    display: flex;
    align-items: baseline;
    gap: 12px;
    margin-top: 4px;
}

.price-current .amount {
    font-size: 2.2rem;
    font-weight: 800;
    color: #10b981;
}

.price-note {
    font-size: 0.88rem;
    color: #cbd5e1;
}

.pricing-notice {
    background: rgba(239, 68, 68, 0.08);
    border: 1px solid rgba(239, 68, 68, 0.2);
    border-radius: var(--radius-sm);
    padding: 14px 18px;
    font-size: 0.88rem;
    color: #fca5a5;
    margin-bottom: 30px;
    line-height: 1.6;
}

.waitlist-form {
    text-align: left;
}

.form-group {
    margin-bottom: 20px;
}

.form-group label {
    display: block;
    font-size: 0.9rem;
    font-weight: 600;
    margin-bottom: 8px;
    color: var(--text-main);
}

.required-star {
    color: #f87171;
}

.form-input {
    width: 100%;
    padding: 14px 16px;
    background: #0f172a;
    border: 1px solid var(--border-color);
    border-radius: var(--radius-sm);
    color: var(--text-main);
    font-family: var(--font-sans);
    font-size: 0.98rem;
    transition: var(--transition);
}

.form-input:focus {
    outline: none;
    border-color: var(--primary);
    box-shadow: 0 0 0 3px rgba(99, 102, 241, 0.2);
}

.form-input.is-invalid {
    border-color: var(--danger) !important;
    box-shadow: 0 0 0 2px rgba(239, 68, 68, 0.25) !important;
}

.form-error {
    color: #f87171;
    font-size: 13px;
    margin-top: 6px;
    display: none;
}

.form-error.is-visible {
    display: block;
}

select.form-input {
    appearance: none;
    background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='16' height='16' viewBox='0 0 24 24' fill='none' stroke='%3C%2394a3b8' stroke-width='2' stroke-linecap='round' stroke-linejoin='round'%3E%3Cpolyline points='6 9 12 15 18 9'%3E%3C/polyline%3E%3C/svg%3E");
    background-repeat: no-repeat;
    background-position: right 16px center;
}

.form-checkbox-group {
    margin-top: 16px;
    margin-bottom: 24px;
}

.checkbox-label {
    display: flex;
    align-items: flex-start;
    gap: 10px;
    font-size: 0.88rem;
    color: var(--text-main);
    cursor: pointer;
    line-height: 1.5;
}

.checkbox-label input[type="checkbox"] {
    margin-top: 3px;
    accent-color: var(--primary);
    width: 17px;
    height: 17px;
    cursor: pointer;
}

.risk-reversal {
    text-align: center;
    font-size: 0.88rem;
    color: #cbd5e1;
    margin-top: 14px;
    font-weight: 500;
}

.form-privacy {
    text-align: center;
    font-size: 0.82rem;
    color: #cbd5e1;
    margin-top: 10px;
}

.spinner {
    display: inline-block;
    width: 16px;
    height: 16px;
    border: 2px solid rgba(255,255,255,0.3);
    border-radius: 50%;
    border-top-color: #ffffff;
    animation: spin 0.8s linear infinite;
    margin-right: 8px;
    vertical-align: middle;
}

@keyframes spin {
    to { transform: rotate(360deg); }
}

/* TICKET PASS */
.hidden { display: none !important; }

.ticket-pass {
    background: linear-gradient(135deg, #064e3b 0%, #022c22 100%);
    border: 2px dashed #10b981;
    border-radius: var(--radius-md);
    padding: 32px;
    margin-top: 20px;
    text-align: left;
    animation: ticketFadeSlide 0.5s cubic-bezier(0.16, 1, 0.3, 1);
}

@keyframes ticketFadeSlide {
    from { opacity: 0; transform: translateY(40px); }
    to { opacity: 1; transform: translateY(0); }
}

.ticket-header {
    border-bottom: 1px solid rgba(16, 185, 129, 0.3);
    padding-bottom: 14px;
    margin-bottom: 16px;
}

.ticket-badge {
    color: #6ee7b7;
    font-size: 0.78rem;
    font-weight: 700;
}

.ticket-header h3 {
    font-size: 1.4rem;
    color: #ffffff;
}

.ticket-body p {
    font-size: 0.95rem;
    color: #a7f3d0;
    margin-bottom: 10px;
}

.ticket-code-row {
    display: flex;
    align-items: center;
    gap: 12px;
    flex-wrap: wrap;
}

.code-highlight {
    font-family: var(--font-mono);
    background: #065f46;
    padding: 4px 10px;
    border-radius: 4px;
    font-weight: 700;
    color: #ffffff;
    letter-spacing: 1px;
}

.copy-code-btn {
    padding: 4px 12px;
    font-size: 0.8rem;
    border-color: rgba(16, 185, 129, 0.4);
    color: #a7f3d0;
}

.copy-code-btn:hover {
    background: rgba(16, 185, 129, 0.2);
    border-color: #10b981;
    color: #ffffff;
}

.ticket-footer {
    margin-top: 16px;
    padding-top: 14px;
    border-top: 1px solid rgba(16, 185, 129, 0.3);
    font-size: 0.85rem;
    color: #6ee7b7;
}

/* ==========================================================================
   SECTION 6: FAQ ACCORDION (ACCESSIBLE GRID ANIMATION)
   ========================================================================== */
.faq-list {
    display: flex;
    flex-direction: column;
    gap: 16px;
}

.faq-item {
    background: var(--bg-card);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-md);
    overflow: hidden;
    transition: var(--transition);
}

.faq-question {
    width: 100%;
    text-align: left;
    padding: 20px 24px;
    background: transparent;
    border: none;
    color: var(--text-main);
    font-family: var(--font-sans);
    font-size: 1.05rem;
    font-weight: 700;
    cursor: pointer;
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.faq-icon {
    font-size: 1.4rem;
    color: var(--primary);
    transition: transform 0.25s ease;
    display: inline-block;
    line-height: 1;
}

.faq-answer {
    display: grid;
    grid-template-rows: 0fr;
    transition: grid-template-rows 0.3s ease, padding 0.3s ease;
    overflow: hidden;
    padding: 0 24px;
}

.faq-answer > p {
    min-height: 0;
    overflow: hidden;
    color: var(--text-muted);
    font-size: 0.95rem;
    line-height: 1.6;
}

.faq-item.active .faq-answer {
    grid-template-rows: 1fr;
    padding: 0 24px 20px;
}

.faq-item.active .faq-icon {
    transform: rotate(45deg);
}

/* ==========================================================================
   MOBILE STICKY CTA BAR (<768PX)
   ========================================================================== */
.mobile-sticky-cta {
    display: none;
}

@media (max-width: 767px) {
    .mobile-sticky-cta {
        display: block;
        position: fixed;
        bottom: 0;
        left: 0;
        right: 0;
        background: rgba(18, 24, 36, 0.95);
        border-top: 1px solid var(--border-glow);
        backdrop-filter: blur(12px);
        padding: 10px 16px;
        z-index: 90;
        transform: translateY(100%);
        transition: transform 0.3s ease;
    }

    .mobile-sticky-cta.is-visible {
        transform: translateY(0);
    }

    .sticky-cta-inner {
        display: flex;
        align-items: center;
        justify-content: space-between;
        max-width: 500px;
        margin: 0 auto;
    }

    .sticky-price-info {
        display: flex;
        flex-direction: column;
    }

    .sticky-label {
        font-size: 0.72rem;
        color: var(--text-muted);
    }

    .sticky-amount {
        font-size: 1.15rem;
        font-weight: 800;
        color: #10b981;
    }
}

/* ==========================================================================
   FLOATING ZALO BUTTON
   ========================================================================== */
.zalo-float {
    position: fixed;
    bottom: 90px; /* Above sticky mobile CTA */
    right: 16px;
    z-index: 900;
    background: #0068FF;
    color: #ffffff;
    border-radius: 999px;
    padding: 12px 18px;
    font-weight: 700;
    font-size: 0.9rem;
    box-shadow: 0 4px 16px rgba(0, 104, 255, 0.45);
    display: inline-flex;
    align-items: center;
    gap: 8px;
    text-decoration: none;
    transition: var(--transition);
}

.zalo-float:hover {
    transform: translateY(-2px);
    box-shadow: 0 6px 20px rgba(0, 104, 255, 0.6);
    color: #ffffff;
}

.zalo-icon {
    background: #ffffff;
    color: #0068FF;
    font-weight: 800;
    font-size: 0.75rem;
    padding: 2px 6px;
    border-radius: 4px;
    letter-spacing: 0.5px;
}

@media (max-width: 767px) {
    .zalo-float {
        padding: 12px 14px;
        border-radius: 50%;
        bottom: 80px;
        right: 14px;
    }
    .zalo-label {
        display: none;
    }
}

/* ==========================================================================
   FOOTER CONTACT BLOCK
   ========================================================================== */
.site-footer {
    background: #06090e;
    border-top: 1px solid var(--border-color);
    padding: 40px 0;
    margin-bottom: 0;
}

@media (max-width: 767px) {
    .site-footer {
        padding-bottom: 75px;
    }
}

.footer-logo {
    font-size: 1.1rem;
    margin-bottom: 8px;
}

.footer-copy {
    color: var(--text-muted);
    font-size: 0.95rem;
    margin-bottom: 16px;
    font-style: italic;
}

.footer-contact-block {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 16px;
    font-size: 15px;
    margin-bottom: 18px;
    flex-wrap: wrap;
}

.footer-contact-item {
    color: var(--text-main);
    display: inline-flex;
    align-items: center;
    gap: 6px;
    transition: var(--transition);
}

.footer-contact-item:hover {
    color: #818cf8;
}

.footer-contact-divider {
    color: var(--text-dim);
}

.footer-subtext {
    color: #94a3b8;
    font-size: 0.8rem;
}

/* ==========================================================================
   RESPONSIVE DESIGN (360px, 768px, 1280px, 1920px)
   ========================================================================== */
@media (max-width: 900px) {
    .site-header .nav-links { display: none; }
    .mobile-menu-btn { display: flex; }
}

@media (max-width: 768px) {
    .hero-title { font-size: 2.1rem; }
    .hero-subtitle { font-size: 1rem; }
    .pain-card-wide { grid-column: span 1; }
    .pricing-card { padding: 24px; }
    .truth-box { padding: 28px; }
    .part-core { grid-column: auto; }
}

/* ==========================================================================
   PREFERS REDUCED MOTION ACCESSIBILITY
   ========================================================================== */
@media (prefers-reduced-motion: reduce) {
    *, ::before, ::after {
        animation-duration: 0.01ms !important;
        animation-iteration-count: 1 !important;
        transition-duration: 0.01ms !important;
        scroll-behavior: auto !important;
    }
    .zalo-float {
        transition: none !important;
        transform: none !important;
    }
}