:root {
    --orange: #FF6700;
    --orange-light: #FFF3E8;
    --blue: #003D99;
    --blue-light: #EBF2FF;
    --dark: #1a1a2e;
    --gray-50: #f8f9fa;
    --gray-100: #f1f3f5;
    --gray-200: #e9ecef;
    --gray-600: #6c757d;
    --gray-800: #343a40;
    --white: #ffffff;
    --shadow: 0 2px 12px rgba(0, 0, 0, 0.08);
    --shadow-lg: 0 8px 30px rgba(0, 0, 0, 0.12);
    --radius: 12px;
    --max-width: 1300px;
}

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

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, 'Helvetica Neue', Arial, sans-serif;
    line-height: 1.7;
    color: var(--gray-800);
    background: var(--white);
}

.container {
    max-width: var(--max-width);
    margin: 0 auto;
    padding: 0 24px;
}

/* Hero / Header */
.hero {
    background: linear-gradient(135deg, #FFF3E8 0%, #FFECD6 100%);
    color: var(--gray-800);
    padding: 60px 0 50px;
    text-align: center;
}

.title {
    font-size: 2.8rem;
    font-weight: 700;
    line-height: 1.3;
    margin-bottom: 24px;
    max-width: 1000px;
    margin-left: auto;
    margin-right: auto;
}

.highlight-orange {
    color: var(--orange);
    font-weight: 800;
}

.highlight-blue {
    color: var(--blue);
}

.authors {
    font-size: 1.3rem;
    margin-bottom: 8px;
    color: var(--gray-800);
    line-height: 2;
    font-weight: 600;
}

.author-notes {
    font-size: 1rem;
    color: var(--gray-600);
    margin-bottom: 16px;
}

.authors span {
    white-space: nowrap;
}

.affiliations {
    font-size: 1rem;
    color: var(--gray-600);
    margin-bottom: 24px;
}

.affiliations p {
    margin: 2px 0;
}

.logos {
    display: flex;
    justify-content: center;
    align-items: center;
    gap: 24px;
    margin-bottom: 28px;
    flex-wrap: wrap;
}

.logos img {
    height: 60px;
    opacity: 0.9;
}

.links {
    display: flex;
    justify-content: center;
    gap: 16px;
    flex-wrap: wrap;
}

.btn {
    display: inline-flex;
    align-items: center;
    gap: 8px;
    padding: 14px 36px;
    border-radius: 8px;
    text-decoration: none;
    font-weight: 600;
    font-size: 1.1rem;
    transition: all 0.2s ease;
    background: #FF9544;
    color: var(--white);
    border: 1px solid #FF9544;
}

.btn:hover {
    background: #e55d00;
    transform: translateY(-1px);
    box-shadow: 0 4px 12px rgba(255, 103, 0, 0.3);
}

.btn-dark {
    background: #4a4a5a;
    border-color: #4a4a5a;
}

.btn-dark:hover {
    background: #3a3a4a;
}

.btn-hf {
    background: #FFE680;
    border-color: #FFE680;
    color: #1a1a2e;
}

.btn-hf:hover {
    background: #FFD21E;
}

/* Hero layout with side images */
.hero-content {
    position: relative;
}

.hero-side {
    position: absolute;
    top: 45%;
    transform: translateY(-50%);
    width: 300px;
}

.hero-left {
    left: -140px;
    top: 40%;
}

.hero-right {
    right: -140px;
}

.hero-side img {
    width: 100%;
    border-radius: 12px;
}

.hero-center {
    width: 100%;
}

@media (max-width: 1200px) {
    .hero-side {
        display: none;
    }
}

/* Sections */
.section {
    padding: 60px 0;
}

.section.alt-bg {
    background: var(--gray-50);
}

.section h2 {
    font-size: 2.4rem;
    font-weight: 700;
    margin-bottom: 28px;
    color: var(--dark);
    text-align: center;
}

.section h3 {
    font-size: 1.25rem;
    font-weight: 600;
    margin-bottom: 16px;
    color: var(--gray-800);
}

/* Abstract */
.abstract-text {
    font-size: 1.2rem;
    line-height: 1.8;
    color: var(--gray-800);
    text-align: justify;
    max-width: 1100px;
    margin: 0 auto;
}

/* Figures */
.figure-wrapper {
    margin: 32px 0;
    text-align: center;
}

.figure-wrapper img {
    max-width: 100%;
    border-radius: var(--radius);
    box-shadow: var(--shadow);
}

.caption {
    margin-top: 12px;
    font-size: 0.9rem;
    color: var(--gray-600);
    max-width: 800px;
    margin-left: auto;
    margin-right: auto;
    text-align: left;
}

/* Method Cards */
.method-cards {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 20px;
    margin-bottom: 32px;
}

.method-cards.three-col {
    grid-template-columns: repeat(3, 1fr);
}

.card {
    background: var(--white);
    padding: 24px;
    border-radius: var(--radius);
    box-shadow: var(--shadow);
    border: 1px solid var(--gray-200);
}

.card h4 {
    font-size: 1rem;
    font-weight: 600;
    margin-bottom: 10px;
    color: var(--orange);
}

.card h4 i {
    margin-right: 6px;
}

.card p {
    font-size: 0.92rem;
    color: var(--gray-600);
    line-height: 1.6;
}

/* Stats Grid */
.stats-grid {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 20px;
    margin-bottom: 36px;
}

.stat-card {
    text-align: center;
    padding: 28px 16px;
    background: var(--white);
    border-radius: var(--radius);
    box-shadow: var(--shadow);
    border: 1px solid var(--gray-200);
}

.stat-number {
    font-size: 2.2rem;
    font-weight: 800;
    color: var(--orange);
}

.stat-label {
    font-size: 0.9rem;
    color: var(--gray-600);
    margin-top: 4px;
}

/* Results */
.results-highlight {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 24px;
    margin-bottom: 24px;
}

.result-box {
    text-align: center;
    padding: 36px 24px;
    background: linear-gradient(135deg, var(--orange-light) 0%, var(--white) 100%);
    border-radius: var(--radius);
    box-shadow: var(--shadow);
    border: 1px solid rgba(255, 103, 0, 0.15);
}

.result-box h3 {
    margin-bottom: 12px;
    color: var(--gray-800);
}

.result-number {
    font-size: 3rem;
    font-weight: 800;
    color: var(--orange);
}

.result-improvement {
    font-size: 0.95rem;
    color: var(--gray-600);
    margin-top: 8px;
    font-weight: 500;
}

.results-desc {
    text-align: center;
    font-size: 1rem;
    color: var(--gray-600);
    max-width: 700px;
    margin: 0 auto;
}

/* Case Studies */
.case-grid {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 24px;
}

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

.case-item h3 {
    margin-bottom: 12px;
    color: var(--gray-800);
}

.case-item h3 i {
    margin-right: 6px;
    color: var(--orange);
}

.case-item img {
    width: 100%;
    border-radius: var(--radius);
    box-shadow: var(--shadow);
}

/* Results Table */
.table-wrapper {
    overflow-x: auto;
    margin-bottom: 8px;
    border-radius: var(--radius);
    box-shadow: var(--shadow-lg);
    border: 1px solid rgba(255, 103, 0, 0.12);
}

.results-table {
    width: 100%;
    border-collapse: collapse;
    font-size: 0.9rem;
    background: var(--white);
}

.results-table thead {
    background: linear-gradient(135deg, #FF6700 0%, #FF9544 100%);
    color: var(--white);
}

.results-table th {
    padding: 14px 16px;
    text-align: center;
    font-weight: 600;
    letter-spacing: 0.3px;
}

.results-table th:first-child {
    text-align: left;
}

.results-table td {
    padding: 10px 16px;
    text-align: center;
    border-bottom: 1px solid rgba(255, 103, 0, 0.06);
}

.results-table td:first-child {
    text-align: left;
}

.results-table tbody tr:hover {
    background: rgba(255, 103, 0, 0.03);
}

.results-table .group-header td {
    background: linear-gradient(90deg, #FFF8F2 0%, #FFF3E8 100%);
    font-weight: 600;
    font-style: italic;
    color: var(--orange);
    font-size: 0.85rem;
    padding: 8px 16px;
    border-left: 3px solid var(--orange);
}

.results-table .highlight-row {
    background: linear-gradient(90deg, #FFF3E8 0%, #FFECD6 100%);
}

.results-table .highlight-row td {
    color: var(--orange);
    font-weight: 700;
    border-bottom: none;
    padding: 12px 16px;
}

/* Citation */
.bibtex {
    background: var(--gray-100);
    padding: 24px;
    border-radius: var(--radius);
    overflow-x: auto;
    font-size: 0.85rem;
    line-height: 1.6;
    border: 1px solid var(--gray-200);
}

.bibtex code {
    font-family: 'SF Mono', 'Fira Code', 'Cascadia Code', monospace;
}

/* Footer */
footer {
    background: var(--dark);
    color: rgba(255, 255, 255, 0.6);
    padding: 24px 0;
    text-align: center;
    font-size: 0.85rem;
}

/* Responsive */
@media (max-width: 768px) {
    .title {
        font-size: 1.5rem;
    }

    .method-cards,
    .method-cards.three-col,
    .stats-grid,
    .results-highlight,
    .case-grid {
        grid-template-columns: 1fr;
    }

    .hero {
        padding: 40px 0 36px;
    }

    .section {
        padding: 40px 0;
    }

    .logos img {
        height: 30px;
    }
}

/* Animations */
@keyframes fadeInUp {
    from {
        opacity: 0;
        transform: translateY(30px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

@keyframes fadeIn {
    from { opacity: 0; }
    to { opacity: 1; }
}

.animate-on-scroll {
    opacity: 0;
    transform: translateY(30px);
    transition: opacity 0.6s ease, transform 0.6s ease;
}

.animate-on-scroll.visible {
    opacity: 1;
    transform: translateY(0);
}

.animate-on-scroll:nth-child(2) { transition-delay: 0.1s; }
.animate-on-scroll:nth-child(3) { transition-delay: 0.2s; }
.animate-on-scroll:nth-child(4) { transition-delay: 0.3s; }

/* Hero entrance */
.hero .title {
    animation: fadeInUp 0.8s ease forwards;
}

.hero .authors {
    animation: fadeInUp 0.8s ease 0.15s forwards;
    opacity: 0;
}

.hero .logos {
    animation: fadeInUp 0.8s ease 0.3s forwards;
    opacity: 0;
}

.hero .links {
    animation: fadeInUp 0.8s ease 0.45s forwards;
    opacity: 0;
}

/* Card hover effects */
.card {
    transition: transform 0.3s ease, box-shadow 0.3s ease;
}

.card:hover {
    transform: translateY(-4px);
    box-shadow: 0 12px 32px rgba(255, 103, 0, 0.12);
}

/* Stat card hover */
.stat-card {
    transition: transform 0.3s ease, box-shadow 0.3s ease;
}

.stat-card:hover {
    transform: translateY(-4px);
    box-shadow: 0 12px 32px rgba(255, 103, 0, 0.15);
}

/* Figure hover zoom */
.figure-wrapper img {
    transition: transform 0.4s ease, box-shadow 0.4s ease;
}

.figure-wrapper img:hover {
    transform: scale(1.02);
    box-shadow: 0 12px 40px rgba(0, 0, 0, 0.15);
}

/* Table wrapper entrance */
.table-wrapper {
    transition: transform 0.3s ease, box-shadow 0.3s ease;
}

.table-wrapper:hover {
    box-shadow: 0 12px 40px rgba(255, 103, 0, 0.15);
}

/* Result box pulse on hover */
.result-box {
    transition: transform 0.3s ease, box-shadow 0.3s ease;
}

.result-box:hover {
    transform: translateY(-4px) scale(1.02);
    box-shadow: 0 16px 40px rgba(255, 103, 0, 0.18);
}

/* Hero side images float animation */
@keyframes float {
    0%, 100% { transform: translateY(-50%) translateX(0); }
    50% { transform: translateY(calc(-50% - 8px)) translateX(0); }
}

.hero-side {
    animation: float 4s ease-in-out infinite;
}

.hero-right {
    animation-delay: 1s;
}

/* Case study image hover */
.case-item img {
    transition: transform 0.4s ease, box-shadow 0.4s ease;
}

.case-item img:hover {
    transform: scale(1.03);
    box-shadow: 0 16px 48px rgba(0, 0, 0, 0.18);
}

@media (max-width: 480px) {
    .title {
        font-size: 1.3rem;
    }

    .authors {
        font-size: 0.9rem;
    }

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