/**
 * DỰ ÁN: BẢO TÀNG KÝ ỨC TRƯƠNG QUANG TRỌNG (LDP-TRUONG-QUANG-TRONG)
 * Tệp: website/css/style.css
 * Hệ thống Component & Trải nghiệm Bảo tàng Lịch sử Quốc gia
 * Ngôn ngữ thị giác: Góc cạnh Tân học (1919-1926) & Chất Thép Ngục Kon Tum (1931)
 * Chuẩn mực: Tự chủ 100% (Zero CDN lock-in); Triệt tiêu hoàn toàn góc bo tròn.
 */

@import url('variables.css');

/* ==========================================================================
   1. RESET & NỀN TẢNG THỊ GIÁC (GLOBAL RESET & TEXTURE)
   ========================================================================== */
*, *::before, *::after {
    box-sizing: border-box;
    margin: 0;
    padding: 0;
}

html {
    scroll-behavior: smooth;
    font-size: 16px;
    scroll-padding-top: 72px;
}

body {
    font-family: var(--font-sans);
    color: var(--color-text-main);
    background-color: var(--color-parchment);
    margin: 0;
    padding: 0;
    overflow-x: hidden;
    position: relative;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
    line-height: 1.6;
}

/* Lớp phủ hạt giấy archival (Vintage Noise Overlay) */
body::before {
    content: '';
    position: fixed;
    top: 0;
    left: 0;
    width: 100vw;
    height: 100vh;
    background-image: var(--texture-noise-filter);
    pointer-events: none;
    z-index: 9999;
    opacity: 0.85;
}

h1, h2, h3, h4, h5, h6, .font-serif {
    font-family: var(--font-serif);
    letter-spacing: -0.01em;
}

.font-display {
    font-family: var(--font-display);
}

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

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

button {
    font-family: inherit;
    border: none;
    background: none;
    cursor: pointer;
}

/* Triệt tiêu triệt để mọi class bo tròn từ Tailwind hoặc CSS ngoài */
.rounded-full, 
.rounded-3xl, 
.rounded-2xl, 
.rounded-xl, 
.rounded-lg, 
.rounded-md, 
.rounded-sm, 
.rounded {
    border-radius: 0px !important;
}

/* Hiệu ứng bóng chữ cho tiêu đề bi tráng */
.text-shadow-monument {
    text-shadow: 0 2px 10px rgba(0, 0, 0, 0.85), 0 4px 20px rgba(74, 0, 0, 0.7);
}

.text-shadow-gold {
    text-shadow: 0 0 16px rgba(245, 158, 11, 0.5), 0 1px 3px rgba(0, 0, 0, 0.9);
}

/* ==========================================================================
   2. HỆ THỐNG LAYOUT & TIỆN ÍCH TỰ CHỦ (SELF-CONTAINED UTILITY ENGINE)
   ========================================================================== */
.monument-section {
    background-color: var(--color-iron-black) !important;
    color: #ffffff !important;
}

.triptych-section {
    background-color: var(--color-parchment) !important;
    border-bottom: 1px solid var(--color-parchment-border);
}

.artifacts-section {
    background-color: var(--color-parchment-warm) !important;
    border-bottom: 1px solid var(--color-parchment-border-dark);
}

.legacy-section {
    background-color: var(--color-parchment) !important;
    border-bottom: 1px solid var(--color-parchment-border);
}

.lumina-portal-section {
    background-color: var(--color-iron-dark) !important;
    color: #ffffff !important;
    border-bottom: 1px solid rgba(184, 134, 11, 0.35);
}

.max-w-7xl { max-width: 80rem; }
.max-w-6xl { max-width: 72rem; }
.max-w-5xl { max-width: 64rem; }
.max-w-4xl { max-width: 56rem; }
.max-w-3xl { max-width: 48rem; }
.max-w-2xl { max-width: 42rem; }
.max-w-md  { max-width: 28rem; }

.mx-auto   { margin-left: auto; margin-right: auto; }
.w-full    { width: 100%; }
.h-full    { height: 100%; }
.w-9       { width: 2.25rem; }
.h-9       { height: 2.25rem; }
.w-10      { width: 2.5rem; }
.h-10      { height: 2.5rem; }
.w-6       { width: 1.5rem; }
.h-4       { height: 1rem; }
.w-4       { width: 1rem; }
.h-\[2px\] { height: 2px; }

/* Positioning */
.relative  { position: relative; }
.absolute  { position: absolute; }
.fixed     { position: fixed; }
.inset-0   { top: 0; right: 0; bottom: 0; left: 0; }
.top-0     { top: 0; }
.bottom-0  { bottom: 0; }
.left-0    { left: 0; }
.right-0   { right: 0; }
.bottom-4  { bottom: 1rem; }
.bottom-6  { bottom: 1.5rem; }
.left-4    { left: 1rem; }
.right-4   { right: 1rem; }
.left-1\/2 { left: 50%; }
.top-1\/2  { top: 50%; }
.-translate-x-1\/2 { transform: translateX(-50%); }
.-translate-y-1\/2 { transform: translateY(-50%); }
.z-10      { z-index: 10; }
.z-20      { z-index: 20; }
.overflow-hidden { overflow: hidden; }

/* Padding & Margin */
.p-2       { padding: 0.5rem; }
.p-3       { padding: 0.75rem; }
.p-4       { padding: 1rem; }
.p-5       { padding: 1.25rem; }
.p-6       { padding: 1.5rem; }
.p-8       { padding: 2rem; }
.px-4      { padding-left: 1rem; padding-right: 1rem; }
.py-2      { padding-top: 0.5rem; padding-bottom: 0.5rem; }
.py-2\.5   { padding-top: 0.625rem; padding-bottom: 0.625rem; }
.py-3      { padding-top: 0.75rem; padding-bottom: 0.75rem; }
.py-4      { padding-top: 1rem; padding-bottom: 1rem; }
.py-5      { padding-top: 1.25rem; padding-bottom: 1.25rem; }
.py-12     { padding-top: 3rem; padding-bottom: 3rem; }
.py-16     { padding-top: 4rem; padding-bottom: 4rem; }
.py-20     { padding-top: 5rem; padding-bottom: 5rem; }
.pt-1      { padding-top: 0.25rem; }
.pt-2      { padding-top: 0.5rem; }
.pt-4      { padding-top: 1rem; }
.pb-8      { padding-bottom: 2rem; }

.mb-1      { margin-bottom: 0.25rem; }
.mb-2      { margin-bottom: 0.5rem; }
.mb-3      { margin-bottom: 0.75rem; }
.mb-4      { margin-bottom: 1rem; }
.mb-6      { margin-bottom: 1.5rem; }
.mb-8      { margin-bottom: 2rem; }
.mb-14     { margin-bottom: 3.5rem; }
.mb-16     { margin-bottom: 4rem; }
.ml-3      { margin-left: 0.75rem; }
.-mt-0\.5  { margin-top: -0.125rem; }

/* Flexbox */
.flex          { display: flex; }
.inline-flex   { display: inline-flex; }
.flex-col      { flex-direction: column; }
.flex-wrap     { flex-wrap: wrap; }
.flex-1        { flex: 1 1 0%; }
.flex-shrink-0 { flex-shrink: 0; }
.items-center  { align-items: center; }
.items-start   { align-items: flex-start; }
.justify-center{ justify-content: center; }
.justify-between{ justify-content: space-between; }

.gap-1         { gap: 0.25rem; }
.gap-1\.5      { gap: 0.375rem; }
.gap-2         { gap: 0.5rem; }
.gap-3         { gap: 0.75rem; }
.gap-4         { gap: 1rem; }
.gap-6         { gap: 1.5rem; }
.gap-8         { gap: 2rem; }
.space-x-1 > * + * { margin-left: 0.25rem; }
.space-x-2 > * + * { margin-left: 0.5rem; }
.space-y-1\.5 > * + * { margin-top: 0.375rem; }
.space-y-2 > * + * { margin-top: 0.5rem; }
.space-y-3 > * + * { margin-top: 0.75rem; }
.space-y-4 > * + * { margin-top: 1rem; }

/* Grid */
.grid { display: grid; }
.grid-cols-1 { grid-template-columns: repeat(1, minmax(0, 1fr)); }

/* Typography */
.text-center   { text-align: center; }
.uppercase     { text-transform: uppercase; }
.italic        { font-style: italic; }
.font-black    { font-weight: 900; }
.font-bold     { font-weight: 700; }
.font-semibold { font-weight: 600; }
.font-medium   { font-weight: 500; }
.font-light    { font-weight: 300; }
.tracking-tight { letter-spacing: -0.025em; }
.tracking-wide  { letter-spacing: 0.025em; }
.tracking-wider { letter-spacing: 0.05em; }
.tracking-widest{ letter-spacing: 0.1em; }
.leading-tight { line-height: 1.25; }
.leading-snug  { line-height: 1.375; }
.leading-relaxed{ line-height: 1.625; }

.text-\[9px\]  { font-size: 9px; }
.text-\[10px\] { font-size: 10px; }
.text-\[11px\] { font-size: 11px; }
.text-xs       { font-size: 0.75rem; line-height: 1rem; }
.text-sm       { font-size: 0.875rem; line-height: 1.25rem; }
.text-base     { font-size: 1rem; line-height: 1.5rem; }
.text-lg       { font-size: 1.125rem; line-height: 1.75rem; }
.text-xl       { font-size: 1.25rem; line-height: 1.75rem; }
.text-2xl      { font-size: 1.5rem; line-height: 2rem; }
.text-3xl      { font-size: 1.875rem; line-height: 2.25rem; }
.text-4xl      { font-size: 2.25rem; line-height: 2.5rem; }
.text-5xl      { font-size: 3rem; line-height: 1.1; }
.text-6xl      { font-size: 3.75rem; line-height: 1; }
.text-7xl      { font-size: 4.5rem; line-height: 1; }

/* Colors */
.text-white       { color: #ffffff !important; }
.text-amber-200   { color: #fde68a !important; }
.text-amber-300   { color: #fcd34d !important; }
.text-amber-400   { color: #fbbf24 !important; }
.text-amber-500   { color: #f59e0b !important; }
.text-amber-700   { color: #b45309 !important; }
.text-amber-800   { color: #92400e !important; }
.text-amber-900   { color: #78350f !important; }
.text-red-700     { color: #b91c1c !important; }
.text-red-800     { color: #991b1b !important; }
.text-red-900     { color: #7f1d1d !important; }
.text-slate-200   { color: #e2e8f0 !important; }
.text-slate-300   { color: #cbd5e1 !important; }
.text-slate-400   { color: #94a3b8 !important; }
.text-slate-500   { color: #64748b !important; }
.text-slate-600   { color: #475569 !important; }
.text-slate-700   { color: #334155 !important; }
.text-slate-800   { color: #1e293b !important; }
.text-slate-900   { color: #0f172a !important; }

.bg-black         { background-color: #000000 !important; }
.bg-black\/40     { background-color: rgba(0, 0, 0, 0.4) !important; }
.bg-black\/60     { background-color: rgba(0, 0, 0, 0.6) !important; }
.bg-black\/80     { background-color: rgba(0, 0, 0, 0.8) !important; }
.bg-white         { background-color: #ffffff !important; }
.bg-white\/40     { background-color: rgba(255, 255, 255, 0.4) !important; }
.bg-slate-900     { background-color: #0f172a !important; }
.bg-slate-950     { background-color: #020617 !important; }
.bg-slate-100     { background-color: #f1f5f9 !important; }
.bg-amber-50      { background-color: #fffbeb !important; }
.bg-amber-100     { background-color: #fef3c7 !important; }
.bg-amber-500\/20 { background-color: rgba(245, 158, 11, 0.2) !important; }
.bg-amber-500     { background-color: #f59e0b !important; }
.bg-red-50        { background-color: #fef2f2 !important; }
.bg-red-100       { background-color: #fee2e2 !important; }
.bg-red-800       { background-color: #991b1b !important; }
.bg-red-950\/80   { background-color: rgba(69, 10, 10, 0.8) !important; }

/* Borders */
.border           { border-width: 1px; border-style: solid; border-color: #e2e8f0; }
.border-t         { border-top-width: 1px; border-top-style: solid; border-top-color: #e2e8f0; }
.border-b         { border-bottom-width: 1px; border-bottom-style: solid; border-bottom-color: #e2e8f0; }
.border-l-2       { border-left-width: 2px; border-left-style: solid; }
.border-l-4       { border-left-width: 4px; border-left-style: solid; }
.border-t-4       { border-top-width: 4px; border-top-style: solid; }

.border-slate-200 { border-color: #e2e8f0 !important; }
.border-slate-300 { border-color: #cbd5e1 !important; }
.border-slate-700 { border-color: #334155 !important; }
.border-slate-800 { border-color: #1e293b !important; }
.border-amber-200\/60 { border-color: rgba(253, 230, 138, 0.6) !important; }
.border-amber-400 { border-color: #fbbf24 !important; }
.border-amber-500\/30 { border-color: rgba(245, 158, 11, 0.3) !important; }
.border-amber-500\/40 { border-color: rgba(245, 158, 11, 0.4) !important; }
.border-amber-500\/50 { border-color: rgba(245, 158, 11, 0.5) !important; }
.border-amber-600 { border-color: #d97706 !important; }
.border-amber-600\/30 { border-color: rgba(217, 119, 6, 0.3) !important; }
.border-amber-600\/40 { border-color: rgba(217, 119, 6, 0.4) !important; }
.border-red-200\/60 { border-color: rgba(254, 202, 202, 0.6) !important; }
.border-red-700   { border-color: #b91c1c !important; }
.border-red-800   { border-color: #991b1b !important; }
.border-t-red-800 { border-top-color: #991b1b !important; }
.border-t-amber-600 { border-top-color: #d97706 !important; }
.border-t-slate-900 { border-top-color: #0f172a !important; }

/* Responsive Media Queries */
@media (min-width: 640px) {
    .sm\:text-base { font-size: 1rem; line-height: 1.5rem; }
    .sm\:text-lg   { font-size: 1.125rem; line-height: 1.75rem; }
    .sm\:text-xl   { font-size: 1.25rem; line-height: 1.75rem; }
    .sm\:text-2xl  { font-size: 1.5rem; line-height: 2rem; }
    .sm\:text-3xl  { font-size: 1.875rem; line-height: 2.25rem; }
    .sm\:text-4xl  { font-size: 2.25rem; line-height: 2.5rem; }
    .sm\:text-5xl  { font-size: 3rem; line-height: 1.1; }
    .sm\:text-6xl  { font-size: 3.75rem; line-height: 1; }
    .sm\:py-28     { padding-top: 7rem; padding-bottom: 7rem; }
    .sm\:p-3       { padding: 0.75rem; }
    .sm\:p-8       { padding: 2rem; }
    .sm\:px-6      { padding-left: 1.5rem; padding-right: 1.5rem; }
    .sm\:gap-4     { gap: 1rem; }
    .sm\:flex-row  { flex-direction: row; }
}

@media (min-width: 768px) {
    .md\:grid-cols-3  { grid-template-columns: repeat(3, minmax(0, 1fr)); }
    .md\:grid-cols-12 { grid-template-columns: repeat(12, minmax(0, 1fr)); }
    .md\:col-span-3   { grid-column: span 3 / span 3; }
    .md\:col-span-4   { grid-column: span 4 / span 4; }
    .md\:col-span-5   { grid-column: span 5 / span 5; }
    .md\:col-span-7   { grid-column: span 7 / span 7; }
    .md\:text-4xl     { font-size: 2.25rem; line-height: 2.5rem; }
    .md\:text-5xl     { font-size: 3rem; line-height: 1.1; }
    .md\:text-7xl     { font-size: 4.5rem; line-height: 1; }
    .md\:h-96         { height: 24rem; }
    .md\:flex-row     { flex-direction: row; }
}

@media (min-width: 1024px) {
    .lg\:px-8         { padding-left: 2rem; padding-right: 2rem; }
    .lg\:grid-cols-3  { grid-template-columns: repeat(3, minmax(0, 1fr)); }
    .lg\:col-span-7   { grid-column: span 7 / span 7; }
    .lg\:col-span-5   { grid-column: span 5 / span 5; }
    .hidden.lg\:flex  { display: flex !important; }
    .lg\:hidden       { display: none !important; }
}

@media (max-width: 1023px) {
    .hidden.lg\:flex  { display: none !important; }
    .lg\:hidden       { display: block !important; }
}

/* ==========================================================================
   3. GÓC VÁT KIẾN TRÚC & KHUNG DI SẢN (CHAMFER & ARCHITECTURAL FRAMES)
   ========================================================================== */
.chamfer-xs {
    clip-path: var(--clip-chamfer-xs);
}

.chamfer-sm {
    clip-path: var(--clip-chamfer-sm);
}

.chamfer-md {
    clip-path: var(--clip-chamfer-md);
}

.chamfer-lg {
    clip-path: var(--clip-chamfer-lg);
}

.chamfer-hero {
    clip-path: var(--clip-chamfer-hero);
}

.cut-corner-tr {
    clip-path: var(--clip-cut-tr);
}

.cut-corner-br {
    clip-path: var(--clip-cut-br);
}

/* ==========================================================================
   4. THANH ĐIỀU HƯỚNG TỐI GIẢN & RESPONSIVE (MINIMALIST NAVBAR)
   ========================================================================== */
.museum-nav {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 64px;
    z-index: var(--z-nav);
    background: rgba(11, 15, 25, 0.94);
    backdrop-filter: blur(12px);
    -webkit-backdrop-filter: blur(12px);
    border-bottom: 1px solid rgba(184, 134, 11, 0.35);
    transition: background-color var(--transition-normal), border-color var(--transition-normal), box-shadow var(--transition-normal);
}

.museum-nav.scrolled {
    background: rgba(7, 10, 17, 0.98);
    border-bottom-color: var(--color-crimson);
    box-shadow: 0 4px 20px rgba(0, 0, 0, 0.6);
}

.nav-brand-seal {
    width: 36px;
    height: 36px;
    background: linear-gradient(135deg, #8b0000 0%, #4a0000 100%);
    border: 1px solid var(--color-gold);
    display: flex;
    align-items: center;
    justify-content: center;
    color: var(--color-gold-bright);
    font-family: var(--font-serif);
    font-weight: 700;
    font-size: 1.1rem;
    clip-path: var(--clip-chamfer-xs);
    box-shadow: 0 2px 6px rgba(0, 0, 0, 0.5);
    transition: transform var(--transition-fast);
}

.nav-brand-link:hover .nav-brand-seal {
    transform: scale(1.05);
    border-color: #ffffff;
}

.nav-link {
    color: #e2e8f0;
    font-size: var(--text-xs);
    font-weight: 600;
    letter-spacing: 0.08em;
    text-transform: uppercase;
    padding: 0.5rem 0.75rem;
    position: relative;
    transition: color var(--transition-fast);
}

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

.nav-link:hover, .nav-link.active {
    color: var(--color-gold-bright);
}

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

.nav-lumina-btn {
    display: inline-flex;
    align-items: center;
    gap: 0.375rem;
    font-size: var(--text-xs);
    font-weight: 700;
    letter-spacing: 0.06em;
    text-transform: uppercase;
    color: var(--color-gold-bright);
    background: rgba(184, 134, 11, 0.12);
    border: 1px solid var(--color-gold);
    padding: 0.35rem 0.85rem;
    clip-path: var(--clip-chamfer-xs);
    transition: all var(--transition-fast);
}

.nav-lumina-btn:hover {
    background: var(--color-gold);
    color: #000000;
    box-shadow: 0 0 12px rgba(184, 134, 11, 0.4);
}

/* Mobile Menu Drawer */
.mobile-drawer {
    background: rgba(11, 15, 25, 0.98);
    border-bottom: 2px solid var(--color-crimson);
    backdrop-filter: blur(16px);
    display: flex;
    flex-direction: column;
    padding: 1rem 1.5rem;
    gap: 0.5rem;
}

.mobile-drawer a {
    display: block;
    padding: 0.6rem 1rem;
    color: #e2e8f0;
    font-size: var(--text-sm);
    font-weight: 600;
    letter-spacing: 0.08em;
    text-transform: uppercase;
    text-align: center;
    border-bottom: 1px solid rgba(255, 255, 255, 0.06);
    transition: all var(--transition-fast);
}

.mobile-drawer a:hover {
    color: var(--color-gold-bright);
    background: rgba(184, 134, 11, 0.1);
}

/* ==========================================================================
   5. SẢNH ĐÓN HERO SECTION & AUDIO ATMOSPHERE
   ========================================================================== */
.hero-wrapper {
    position: relative;
    min-height: 100vh;
    display: flex;
    align-items: center;
    justify-content: center;
    padding: 7rem 1.5rem 5rem;
    background: 
        radial-gradient(circle at 50% 30%, rgba(139, 0, 0, 0.45) 0%, rgba(11, 15, 25, 0.94) 75%),
        linear-gradient(180deg, rgba(11, 15, 25, 0.85) 0%, rgba(11, 15, 25, 0.98) 100%),
        url('../assets/images/chan-dung-truong-quang-trong.jpg') center 20%/cover no-repeat;
    background-attachment: fixed;
    color: #ffffff;
}

.hero-monument-badge {
    display: inline-flex;
    align-items: center;
    gap: 0.5rem;
    background: rgba(184, 134, 11, 0.15);
    border: 1px solid var(--color-gold);
    color: var(--color-gold-bright);
    padding: 0.35rem 1.25rem;
    clip-path: var(--clip-chamfer-xs);
    font-size: var(--text-xs);
    font-weight: 700;
    letter-spacing: 0.14em;
    text-transform: uppercase;
    backdrop-filter: blur(6px);
    margin-bottom: 1.5rem;
}

/* Nút bấm Plaque kim loại vát góc (Chamfered Metal Action Plates) */
.btn-chamfer-crimson {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: 0.625rem;
    background: linear-gradient(135deg, #a00000 0%, #700000 100%);
    color: #ffffff !important;
    border: 1px solid rgba(255, 255, 255, 0.25);
    border-left: 3px solid var(--color-gold-bright);
    padding: 0.85rem 1.75rem;
    clip-path: var(--clip-chamfer-sm);
    font-size: var(--text-sm);
    font-weight: 700;
    letter-spacing: 0.06em;
    text-transform: uppercase;
    cursor: pointer;
    box-shadow: 0 4px 14px rgba(139, 0, 0, 0.5);
    transition: all var(--transition-fast);
}

.btn-chamfer-crimson:hover {
    background: linear-gradient(135deg, #c00000 0%, #8b0000 100%);
    border-color: #ffffff;
    transform: translateY(-2px);
    box-shadow: 0 6px 20px rgba(185, 28, 28, 0.6);
}

.btn-chamfer-gold {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: 0.625rem;
    background: rgba(184, 134, 11, 0.14);
    color: var(--color-gold-bright) !important;
    border: 1px solid var(--color-gold);
    padding: 0.85rem 1.75rem;
    clip-path: var(--clip-chamfer-sm);
    font-size: var(--text-sm);
    font-weight: 700;
    letter-spacing: 0.06em;
    text-transform: uppercase;
    cursor: pointer;
    transition: all var(--transition-fast);
    backdrop-filter: blur(4px);
}

.btn-chamfer-gold:hover {
    background: var(--color-gold);
    color: #0b0f19 !important;
    box-shadow: 0 0 18px rgba(184, 134, 11, 0.45);
    transform: translateY(-2px);
}

.btn-chamfer-steel {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: 0.625rem;
    background: rgba(31, 41, 55, 0.8);
    color: #f1f5f9 !important;
    border: 1px solid rgba(255, 255, 255, 0.18);
    padding: 0.85rem 1.5rem;
    clip-path: var(--clip-chamfer-sm);
    font-size: var(--text-sm);
    font-weight: 600;
    letter-spacing: 0.04em;
    cursor: pointer;
    transition: all var(--transition-fast);
}

.btn-chamfer-steel:hover {
    background: rgba(55, 65, 81, 0.95);
    border-color: var(--color-gold);
    color: var(--color-gold-bright) !important;
    transform: translateY(-2px);
}

/* ==========================================================================
   6. BA GIAI ĐOẠN CUỘC ĐỜI (THE 3-EPOCH HISTORICAL TRIPTYCH)
   ========================================================================== */
.triptych-grid {
    display: grid;
    grid-template-columns: repeat(1, 1fr);
    gap: 1.5rem;
}

@media (min-width: 1024px) {
    .triptych-grid {
        grid-template-columns: repeat(3, 1fr);
        gap: 1.75rem;
    }
}

.triptych-pillar {
    position: relative;
    background: #ffffff;
    border: 1px solid var(--color-parchment-border);
    clip-path: var(--clip-chamfer-md);
    display: flex;
    flex-direction: column;
    justify-content: space-between;
    padding: 2.25rem 1.75rem;
    box-shadow: var(--shadow-architectural-md);
    transition: transform var(--transition-normal), box-shadow var(--transition-normal), border-color var(--transition-normal);
}

.triptych-pillar:hover {
    transform: translateY(-4px);
    box-shadow: var(--shadow-architectural-lg);
    border-color: var(--color-gold);
}

/* Epoch 1: Tân học Pháp - Việt */
.pillar-epoch-1 {
    background: linear-gradient(180deg, #ffffff 0%, #faf6ee 100%);
    border-top: 4px solid var(--color-gold-dark);
}

/* Epoch 2: Thủ lĩnh Bãi khóa Vô sản */
.pillar-epoch-2 {
    background: linear-gradient(180deg, #ffffff 0%, #fdf2f2 100%);
    border-top: 4px solid var(--color-crimson);
}

/* Epoch 3: Đài Tưởng Niệm Ngục Kon Tum */
.pillar-epoch-3 {
    background: linear-gradient(180deg, #161e2e 0%, #0b0f19 100%);
    border-top: 4px solid var(--color-gold-bright);
    color: #ffffff;
    border-color: rgba(255, 255, 255, 0.15);
}

.pillar-year-badge {
    display: inline-block;
    font-family: var(--font-serif);
    font-size: var(--text-xs);
    font-weight: 700;
    letter-spacing: 0.12em;
    text-transform: uppercase;
    padding: 0.25rem 0.75rem;
    clip-path: var(--clip-chamfer-xs);
    margin-bottom: 1rem;
}

.pillar-epoch-1 .pillar-year-badge {
    background: #fef3c7;
    color: #92400e;
    border: 1px solid #fcd34d;
}

.pillar-epoch-2 .pillar-year-badge {
    background: #fee2e2;
    color: #991b1b;
    border: 1px solid #fca5a5;
}

.pillar-epoch-3 .pillar-year-badge {
    background: rgba(184, 134, 11, 0.2);
    color: var(--color-gold-bright);
    border: 1px solid var(--color-gold);
}

/* ==========================================================================
   7. KHO KỶ VẬT SỐ HÓA HD & ARCHIVAL CATALOG CARDS
   ========================================================================== */
.archival-card {
    background: #ffffff;
    border: 1px solid var(--color-parchment-border);
    clip-path: var(--clip-chamfer-sm);
    box-shadow: var(--shadow-architectural-md);
    transition: transform var(--transition-normal), box-shadow var(--transition-normal), border-color var(--transition-normal);
    display: flex;
    flex-direction: column;
}

.archival-card:hover {
    transform: translateY(-5px);
    box-shadow: var(--shadow-architectural-lg);
    border-color: var(--color-gold);
}

.archival-img-frame {
    position: relative;
    width: 100%;
    height: 290px;
    background-color: #111827;
    overflow: hidden;
    cursor: zoom-in;
    border-bottom: 2px solid var(--color-parchment-border);
}

.archival-img-frame img {
    width: 100%;
    height: 100%;
    object-fit: cover;
    object-position: center;
    transition: transform var(--transition-slow);
}

.archival-card:hover .archival-img-frame img {
    transform: scale(1.04);
}

.archival-accession-tag {
    position: absolute;
    top: 0.85rem;
    left: 0.85rem;
    background: rgba(11, 15, 25, 0.9);
    color: var(--color-gold-bright);
    font-size: var(--text-2xs);
    font-weight: 700;
    letter-spacing: 0.1em;
    padding: 0.25rem 0.65rem;
    border: 1px solid rgba(184, 134, 11, 0.5);
    clip-path: var(--clip-chamfer-xs);
    backdrop-filter: blur(4px);
}

/* ==========================================================================
   8. ĐÀI TƯỞNG NIỆM "LE VOICI!" (MONOLITHIC CENOTAPH)
   ========================================================================== */
.monument-cenotaph {
    position: relative;
    background: radial-gradient(circle at center, rgba(139, 0, 0, 0.35) 0%, rgba(11, 15, 25, 0.98) 75%);
    border: 1px solid rgba(184, 134, 11, 0.4);
    box-shadow: 0 0 50px rgba(139, 0, 0, 0.45);
    clip-path: var(--clip-chamfer-lg);
    padding: var(--space-8);
}

.monument-cenotaph::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    height: 3px;
    background: linear-gradient(90deg, transparent, var(--color-gold-bright), var(--color-crimson-bright), transparent);
}

.le-voici-slab-trigger {
    cursor: pointer;
    display: inline-block;
    padding: 1.5rem 2rem;
    background: rgba(0, 0, 0, 0.5);
    border: 2px solid var(--color-gold);
    clip-path: var(--clip-chamfer-md);
    transition: all var(--transition-fast);
}

.le-voici-slab-trigger:hover {
    background: rgba(139, 0, 0, 0.4);
    border-color: #ffffff;
    box-shadow: 0 0 25px rgba(245, 158, 11, 0.4);
    transform: scale(1.02);
}

/* ==========================================================================
   9. FOOTER TỐI GIẢN & TRANG NGHIÊM (MINIMALIST HISTORICAL FOOTER)
   ========================================================================== */
.museum-footer {
    background: #090d15;
    color: #94a3b8;
    border-top: 3px solid var(--color-crimson);
    position: relative;
}

.footer-nav-link {
    color: #cbd5e1;
    font-size: var(--text-sm);
    transition: color var(--transition-fast);
}

.footer-nav-link:hover {
    color: var(--color-gold-bright);
}

/* ==========================================================================
   10. MODAL LIGHTBOX TỐI TÂN & SẮC CẠNH (ARCHIVAL MODAL)
   ========================================================================== */
.modal-backdrop {
    position: fixed;
    inset: 0;
    background: rgba(7, 10, 17, 0.94);
    backdrop-filter: blur(12px);
    -webkit-backdrop-filter: blur(12px);
    z-index: var(--z-modal);
    display: flex;
    align-items: center;
    justify-content: center;
    opacity: 0;
    visibility: hidden;
    pointer-events: none;
    transition: opacity var(--transition-normal), visibility var(--transition-normal);
    padding: 1.5rem;
}

.modal-backdrop.active {
    opacity: 1;
    visibility: visible;
    pointer-events: auto;
}

.modal-container {
    background: #ffffff;
    clip-path: var(--clip-chamfer-md);
    max-width: 900px;
    width: 100%;
    max-height: 92vh;
    overflow-y: auto;
    position: relative;
    border: 2px solid var(--color-gold);
    box-shadow: 0 25px 50px -12px rgba(0, 0, 0, 0.6);
}

.modal-close-btn {
    position: absolute;
    top: 1rem;
    right: 1rem;
    width: 36px;
    height: 36px;
    background: #111827;
    color: #ffffff;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 1.25rem;
    cursor: pointer;
    border: 1px solid var(--color-gold);
    clip-path: var(--clip-chamfer-xs);
    transition: background var(--transition-fast);
    z-index: 10;
}

.modal-close-btn:hover {
    background: var(--color-crimson);
    color: #ffffff;
}

/* ==========================================================================
   11. HIỆU ỨNG CHUYỂN ĐỘNG & CUỘN (ANIMATIONS)
   ========================================================================== */
.fade-in {
    opacity: 1;
    transform: translateY(0);
    transition: opacity 0.5s ease-out, transform 0.5s ease-out;
}

/* ==========================================================================
   12. TƯỢNG ĐÀI BẤT KHUẤT — SÂN KHẤU TỰ DO VƯƠN CAO (FREE-STANDING HERO STAGE)
   Học hỏi chuẩn mực từ Huỳnh Thúc Kháng: Bỏ hộp giam giữ, vươn cao phóng khoáng
   ========================================================================== */
.hero-monument-free-stage {
    position: relative;
    width: 100%;
    min-height: 460px;
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
}

@media (min-width: 640px) {
    .hero-monument-free-stage {
        min-height: 520px;
    }
}

@media (min-width: 1024px) {
    .hero-monument-free-stage {
        min-height: 600px;
    }
}

/* Hào quang ánh sáng thiêng liêng ấm áp phía sau tượng (Dramatic Ambient Glow) */
.monument-ambient-glow {
    position: absolute;
    top: 48%;
    left: 50%;
    transform: translate(-50%, -50%);
    width: 100%;
    max-width: 540px;
    height: 600px;
    background: radial-gradient(circle at 50% 42%, rgba(245, 158, 11, 0.32) 0%, rgba(217, 119, 6, 0.22) 28%, rgba(185, 28, 28, 0.16) 52%, transparent 75%);
    filter: blur(65px);
    pointer-events: none;
    z-index: 1;
}

/* Tượng Đài Bất Khuất Đứng Tự Do (Vươn cao, thanh thoát, không viền hộp, chiều sâu 3D điêu khắc) */
.hero-monument-free-img {
    position: relative;
    z-index: 2;
    width: auto;
    height: auto;
    max-height: 430px;
    object-fit: contain;
    object-position: center bottom;
    /* Ánh sáng ven kịch tính (Dramatic Rim Light) kết hợp lửa ngục Kon Tum và khối đổ bóng sâu */
    filter: drop-shadow(0 22px 42px rgba(0, 0, 0, 0.95)) 
            drop-shadow(0 0 28px rgba(217, 119, 6, 0.42)) 
            drop-shadow(0 0 65px rgba(185, 28, 28, 0.24));
    transition: transform 0.4s cubic-bezier(0.16, 1, 0.3, 1), filter 0.4s ease;
}

@media (min-width: 640px) {
    .hero-monument-free-img {
        max-height: 500px;
    }
}

@media (min-width: 1024px) {
    .hero-monument-free-img {
        max-height: 600px;
    }
}

.hero-monument-free-img:hover {
    transform: scale(1.032) translateY(-6px);
    filter: drop-shadow(0 32px 60px rgba(0, 0, 0, 0.98)) 
            drop-shadow(0 0 46px rgba(245, 158, 11, 0.62)) 
            drop-shadow(0 0 85px rgba(185, 28, 28, 0.38));
}

/* Nút Floating Pill Tương Tác Tinh Tế (Floating Glass Pill Badge) */
.hero-monument-floating-pill {
    position: relative;
    z-index: 3;
    margin-top: 1.25rem;
    display: inline-flex;
    align-items: center;
    gap: 0.6rem;
    padding: 0.55rem 1.25rem;
    background: rgba(11, 15, 25, 0.85);
    backdrop-filter: blur(10px);
    -webkit-backdrop-filter: blur(10px);
    border: 1px solid rgba(217, 119, 6, 0.5);
    clip-path: var(--clip-chamfer-xs);
    font-size: var(--text-xs);
    color: #ffffff;
    box-shadow: 0 8px 24px rgba(0, 0, 0, 0.65), 0 0 15px rgba(217, 119, 6, 0.2);
    transition: all var(--transition-fast);
    cursor: pointer;
}

.hero-monument-floating-pill:hover {
    background: rgba(185, 28, 28, 0.92);
    border-color: var(--color-gold);
    transform: translateY(-2px);
    box-shadow: 0 12px 28px rgba(185, 28, 28, 0.55), 0 0 25px rgba(217, 119, 6, 0.45);
    color: #ffffff;
}

.hero-monument-floating-pill:hover .text-amber-200 {
    color: #ffffff;
}

/* ==========================================================================
   13. DEFENSIVE RESPONSIVE & UTILITY FALLBACKS (OFFLINE / CDN RESILIENCY)
   ========================================================================== */
.hidden {
    display: none !important;
}

@media (max-width: 767px) {
    .grid {
        display: flex !important;
        flex-direction: column !important;
    }
}

@media (max-width: 1023px) {
    .lg\:flex {
        display: none !important;
    }
}

@media (min-width: 768px) {
    .md\:grid-cols-12 {
        display: grid !important;
        grid-template-columns: repeat(12, minmax(0, 1fr)) !important;
    }
    .md\:grid-cols-3 {
        display: grid !important;
        grid-template-columns: repeat(3, minmax(0, 1fr)) !important;
    }
    .md\:col-span-5 {
        grid-column: span 5 / span 5 !important;
    }
    .md\:col-span-7 {
        grid-column: span 7 / span 7 !important;
    }
    .md\:col-span-4 {
        grid-column: span 4 / span 4 !important;
    }
    .md\:col-span-3 {
        grid-column: span 3 / span 3 !important;
    }
    .md\:col-span-6 {
        grid-column: span 6 / span 6 !important;
    }
    .md\:flex-row {
        flex-direction: row !important;
    }
}

@media (min-width: 1024px) {
    .lg\:flex {
        display: flex !important;
    }
    .lg\:hidden {
        display: none !important;
    }
    .grid {
        display: grid !important;
    }
    .lg\:grid-cols-12 {
        display: grid !important;
        grid-template-columns: repeat(12, minmax(0, 1fr)) !important;
    }
    .lg\:col-span-8 {
        grid-column: span 8 / span 8 !important;
    }
    .lg\:col-span-7 {
        grid-column: span 7 / span 7 !important;
    }
    .lg\:col-span-5 {
        grid-column: span 5 / span 5 !important;
    }
    .lg\:col-span-4 {
        grid-column: span 4 / span 4 !important;
    }
    .lg\:col-span-3 {
        grid-column: span 3 / span 3 !important;
    }
    .lg\:text-left {
        text-align: left !important;
    }
    .lg\:justify-start {
        justify-content: flex-start !important;
    }
    .lg\:justify-end {
        justify-content: flex-end !important;
    }
    .lg\:flex-row {
        flex-direction: row !important;
    }
    .lg\:items-center {
        align-items: center !important;
    }
}

/* ==========================================================================
   SECTION 3: MẮT XÍCH TRUNG TÂM THẾ HỆ VÀNG (ORBITAL NEXUS MATRIX)
   ========================================================================== */
.nexus-section {
    background-color: var(--color-paper-light);
    background-image: 
        radial-gradient(circle at 50% 15%, rgba(184, 134, 11, 0.08) 0%, transparent 60%),
        linear-gradient(rgba(0, 0, 0, 0.03) 1px, transparent 1px),
        linear-gradient(90deg, rgba(0, 0, 0, 0.03) 1px, transparent 1px);
    background-size: 100% 100%, 32px 32px, 32px 32px;
    border-top: 1px solid rgba(184, 134, 11, 0.25);
    border-bottom: 1px solid rgba(184, 134, 11, 0.25);
}

.nexus-container {
    max-width: 1280px;
    margin: 0 auto;
    padding: 0 1rem;
}

.nexus-badge-tag {
    display: inline-flex;
    align-items: center;
    gap: 0.5rem;
    font-size: var(--text-2xs);
    font-weight: 700;
    text-transform: uppercase;
    letter-spacing: 0.15em;
    color: var(--color-crimson);
    background: rgba(185, 28, 28, 0.08);
    border: 1px solid rgba(185, 28, 28, 0.25);
    padding: 0.35rem 0.85rem;
    clip-path: var(--clip-chamfer-xs);
    margin-bottom: 0.75rem;
}

/* Card Trung Tâm (The Central Medallion) */
.nexus-center-card {
    background: #ffffff;
    border: 2px solid var(--color-gold);
    clip-path: var(--clip-chamfer-md);
    box-shadow: 0 12px 32px -8px rgba(184, 134, 11, 0.2), 0 4px 12px rgba(0, 0, 0, 0.05);
    position: relative;
    overflow: hidden;
}

.nexus-center-card::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    height: 4px;
    background: linear-gradient(90deg, #b8860b, #dc2626, #b8860b);
}

.nexus-avatar-frame {
    position: relative;
    width: 108px;
    height: 108px;
    margin: 0 auto;
    padding: 4px;
    background: linear-gradient(135deg, #d4af37, #b8860b, #78350f);
    clip-path: var(--clip-chamfer-sm);
    box-shadow: 0 4px 16px rgba(184, 134, 11, 0.35);
}

.nexus-avatar-img {
    width: 100%;
    height: 100%;
    object-fit: cover;
    clip-path: var(--clip-chamfer-sm);
    background-color: #0b0f19;
}

.nexus-stat-pill {
    display: inline-flex;
    flex-direction: column;
    align-items: center;
    padding: 0.5rem 0.75rem;
    background: rgba(184, 134, 11, 0.08);
    border: 1px solid rgba(184, 134, 11, 0.25);
    clip-path: var(--clip-chamfer-xs);
}

/* Các Quỹ Đạo Vệ Tinh (Satellite Orbit Pods) */
.nexus-pods-grid {
    display: grid;
    grid-template-columns: 1fr;
    gap: 1.5rem;
}

@media (min-width: 1024px) {
    .nexus-pods-grid {
        grid-template-columns: repeat(3, 1fr);
    }
}

.nexus-pod {
    background: #ffffff;
    border: 1px solid var(--color-border);
    clip-path: var(--clip-chamfer-sm);
    box-shadow: var(--shadow-sm);
    display: flex;
    flex-direction: column;
    justify-content: space-between;
    transition: all var(--transition-fast);
    position: relative;
}

.nexus-pod:hover {
    transform: translateY(-3px);
    box-shadow: var(--shadow-md);
}

.nexus-pod-epoch-1 {
    border-top: 4px solid var(--color-gold);
}

.nexus-pod-epoch-2 {
    border-top: 4px solid var(--color-crimson);
}

.nexus-pod-epoch-3 {
    border-top: 4px solid #334155;
    background: linear-gradient(to bottom, #ffffff, #f8fafc);
}

.nexus-pod-header {
    padding: 1.25rem 1.25rem 0.75rem 1.25rem;
    border-bottom: 1px solid rgba(0, 0, 0, 0.06);
}

.nexus-pod-title {
    font-family: var(--font-serif);
    font-size: var(--text-base);
    font-weight: 700;
    line-height: 1.3;
    color: var(--color-text-dark);
}

.nexus-pod-body {
    padding: 1rem 1.25rem;
    flex: 1;
}

.nexus-node-list {
    display: flex;
    flex-direction: column;
    gap: 0.75rem;
}

.nexus-node-item {
    display: flex;
    align-items: flex-start;
    gap: 0.75rem;
    padding: 0.6rem 0.75rem;
    background: #fafaf9;
    border: 1px solid rgba(0, 0, 0, 0.05);
    clip-path: var(--clip-chamfer-xs);
    transition: all var(--transition-fast);
}

.nexus-node-item:hover {
    background: #ffffff;
    border-color: var(--color-gold);
    box-shadow: 0 2px 8px rgba(184, 134, 11, 0.15);
}

.nexus-node-icon {
    width: 28px;
    height: 28px;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: var(--text-xs);
    font-weight: 700;
    clip-path: var(--clip-chamfer-xs);
    flex-shrink: 0;
    margin-top: 2px;
}

.icon-gold {
    background: rgba(184, 134, 11, 0.15);
    color: #92400e;
    border: 1px solid rgba(184, 134, 11, 0.3);
}

.icon-red {
    background: rgba(185, 28, 28, 0.12);
    color: #991b1b;
    border: 1px solid rgba(185, 28, 28, 0.25);
}

.icon-iron {
    background: rgba(51, 65, 85, 0.15);
    color: #1e293b;
    border: 1px solid rgba(51, 65, 85, 0.3);
}

.nexus-node-name {
    font-family: var(--font-serif);
    font-size: var(--text-sm);
    font-weight: 700;
    color: var(--color-text-dark);
    line-height: 1.25;
}

.nexus-node-role {
    font-size: 11px;
    color: var(--color-text-muted);
    line-height: 1.4;
    margin-top: 0.2rem;
}

.nexus-pod-footer {
    padding: 0.75rem 1.25rem;
    background: #fcfbf9;
    border-top: 1px solid rgba(0, 0, 0, 0.05);
    display: flex;
    align-items: center;
    justify-content: space-between;
    font-size: var(--text-2xs);
    font-weight: 600;
    text-transform: uppercase;
    letter-spacing: 0.05em;
}

/* Banner Thống kê & Mở rộng Lumina */
.nexus-stats-strip {
    margin-top: 2.5rem;
    padding: 1.25rem 1.5rem;
    background: #0f172a;
    border: 1px solid rgba(184, 134, 11, 0.4);
    clip-path: var(--clip-chamfer-sm);
    color: #ffffff;
    display: flex;
    flex-direction: column;
    gap: 1rem;
    align-items: center;
    justify-content: space-between;
}

@media (min-width: 768px) {
    .nexus-stats-strip {
        flex-direction: row;
    }
}

/* Sách Ký Sự Lê Văn Hiến Feature Card */
.book-showcase-frame {
    position: relative;
    border: 1px solid rgba(184, 134, 11, 0.4);
    clip-path: var(--clip-chamfer-sm);
    overflow: hidden;
    background: #0b0f19;
    box-shadow: 0 10px 30px rgba(0, 0, 0, 0.5);
}

.book-showcase-frame img {
    transition: transform var(--transition-normal);
}

.book-showcase-frame:hover img {
    transform: scale(1.03);
}

.book-accession-tag {
    position: absolute;
    top: 10px;
    left: 10px;
    background: rgba(0, 0, 0, 0.85);
    color: var(--color-gold-bright);
    font-size: 10px;
    font-family: var(--font-mono);
    padding: 3px 8px;
    border: 1px solid rgba(245, 158, 11, 0.4);
    clip-path: var(--clip-chamfer-xs);
    text-transform: uppercase;
    letter-spacing: 0.05em;
    z-index: 2;
}

/* Huy hiệu đồng chí vệ tinh (Companion Comrades Chips) */
.comrade-nexus-box {
    margin-top: 1.25rem;
    padding-top: 1rem;
    border-top: 1px dashed rgba(184, 134, 11, 0.35);
}

.comrade-badge {
    display: inline-flex;
    align-items: center;
    gap: 0.35rem;
    font-size: var(--text-2xs);
    font-weight: 700;
    letter-spacing: 0.04em;
    padding: 0.25rem 0.6rem;
    clip-path: var(--clip-chamfer-xs);
    cursor: pointer;
    transition: all var(--transition-fast);
    margin-right: 0.35rem;
    margin-bottom: 0.35rem;
}

.comrade-badge-gold {
    background: rgba(184, 134, 11, 0.14);
    color: #92400e;
    border: 1px solid #fcd34d;
}

.comrade-badge-gold:hover {
    background: #b8860b;
    color: #ffffff;
}

.comrade-badge-red {
    background: rgba(185, 28, 28, 0.12);
    color: #991b1b;
    border: 1px solid #fca5a5;
}

.comrade-badge-red:hover {
    background: #991b1b;
    color: #ffffff;
}

.comrade-badge-iron {
    background: rgba(255, 255, 255, 0.08);
    color: var(--color-gold-bright);
    border: 1px solid rgba(245, 158, 11, 0.4);
}

.comrade-badge-iron:hover {
    background: var(--color-gold-bright);
    color: #0b0f19;
}