/* --- AMiS-2027 Conference Master Stylesheet --- */
:root {
    --primary-slate: #4c4b74;
    --primary-dark: #373656;
    --accent-purple: #5e3fde;
    --accent-hover: #482dc2;
    --navy-dark: #102136;
    --bg-light: #f8fafc;
    --text-dark: #1a1a1a;
    --text-muted: #556270;
    --silver-text: #e2e8f0;
    --white: #ffffff;
    --border-color: #e2e8f0;
    --font-stack: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Oxygen, Ubuntu, Cantarell, sans-serif;
}

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

body {
    font-family: var(--font-stack);
    color: var(--text-dark);
    background-color: var(--white);
    line-height: 1.6;
}

.container {
    width: 92%;
    max-width: 1280px;
    margin: 0 auto;
}

/* --- Optional Pre-Header Announcement Bar --- */
.top-announcement-bar {
    background-color: #383756;
    color: #f1f5f9;
    font-size: 13px;
    font-weight: 600;
    padding: 9px 0;
    border-bottom: 1px solid rgba(255, 255, 255, 0.1);
    letter-spacing: 0.5px;
}
.top-announcement-bar i {
    color: #fcd34d;
    margin-right: 6px;
}

/* --- Main Header Bar (Seamless Slate-Purple) --- */
.site-header {
    background-color: var(--primary-slate);
    border-bottom: 1px solid rgba(255, 255, 255, 0.12);
    position: sticky;
    top: 0;
    z-index: 1000;
}

.header-container {
    width: 96%;
    max-width: 1440px;
    margin: 0 auto;
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: 10px 0;
    gap: 15px;
}

/* Header Left: Logo */
.header-left {
    flex: 0 0 auto;
}
.site-logo-link {
    display: flex;
    align-items: center;
    text-decoration: none;
}
.site-logo-img {
    height: 72px;
    width: auto;
    object-fit: contain;
    display: block;
}

/* Header Center: 3-Tier Identity */
.header-center {
    flex: 1 1 auto;
    text-align: center;
}
.conf-identity {
    display: inline-flex;
    flex-direction: column;
    align-items: center;
    line-height: 1.2;
}
.conf-sub {
    font-size: 10px;
    font-weight: 400;
    letter-spacing: 2px;
    color: var(--silver-text);
    text-transform: uppercase;
    opacity: 0.9;
    margin-bottom: 3px;
}
.conf-main {
    font-size: 20px;
    letter-spacing: 1px;
    text-transform: uppercase;
    color: var(--white);
    margin-bottom: 4px;
}
.conf-main .bold {
    font-weight: 800;
}
.conf-main .light {
    font-weight: 200;
    opacity: 0.85;
    margin-left: 4px;
}
.conf-meta {
    font-size: 12px;
    font-weight: 600;
    letter-spacing: 1.5px;
    color: var(--silver-text);
    opacity: 0.95;
    text-transform: uppercase;
}

/* Header Right: Menu & CTA */
.header-right {
    flex: 0 0 auto;
    display: flex;
    align-items: center;
    gap: 18px;
}
.main-nav ul {
    display: flex;
    list-style: none;
    gap: 18px;
    align-items: center;
}
.main-nav a {
    color: var(--silver-text);
    text-decoration: none;
    font-size: 14px;
    font-weight: 600;
    transition: color 0.2s ease;
}
.main-nav a:hover, .main-nav a.active {
    color: var(--white);
    border-bottom: 2px solid var(--accent-purple);
    padding-bottom: 2px;
}
.btn-header-action {
    background-color: var(--navy-dark);
    color: var(--white);
    padding: 8px 18px;
    font-size: 13px;
    font-weight: 700;
    border-radius: 4px;
    text-decoration: none;
    border: 1px solid rgba(255, 255, 255, 0.2);
    transition: all 0.2s ease;
}
.btn-header-action:hover {
    background-color: var(--accent-purple);
    border-color: var(--accent-purple);
}

.mobile-toggle {
    display: none;
    background: none;
    border: none;
    font-size: 24px;
    color: var(--white);
    cursor: pointer;
}

/* --- Hero Section (Crisp Graphene Layer + Downward Extension) --- */
/* --- Hero Section (Vibrant, Crystal-Clear Graphene) --- */
.hero-section {
    background-color: var(--primary-slate);
    background-image: 
        linear-gradient(to right, 
            rgba(76, 75, 116, 0.96) 0%, 
            rgba(76, 75, 116, 0.85) 30%, 
            rgba(76, 75, 116, 0.20) 55%, 
            rgba(76, 75, 116, 0) 70%
        ),
        url('../images/adminsys.png');
    background-position: right center;
    background-size: cover;
    background-repeat: no-repeat;
    color: var(--white);
    padding: 140px 0 160px;
    min-height: 82vh;
    display: flex;
    align-items: center;
}

.hero-content {
    max-width: 640px; /* Left-aligned ~50% so honeycomb graphic shows on right */
    margin-left: 0;
}

.hero-tag {
    font-size: 12px;
    font-weight: 800;
    letter-spacing: 2px;
    color: var(--silver-text);
    margin-bottom: 14px;
    display: inline-block;
    text-transform: uppercase;
}

.hero-content h1 {
    font-size: 44px;
    font-weight: 800;
    line-height: 1.25;
    margin-bottom: 20px;
    color: var(--white);
}

.hero-content p {
    font-size: 16px;
    line-height: 1.7;
    margin-bottom: 40px;
    color: #f1f5f9;
}

/* Hero 3 CTA Buttons */
.hero-actions {
    display: flex;
    gap: 14px;
    flex-wrap: wrap;
    align-items: center;
}

.btn {
    display: inline-block;
    padding: 12px 26px;
    border-radius: 4px;
    font-size: 14px;
    font-weight: 700;
    text-decoration: none;
    cursor: pointer;
    transition: all 0.2s ease;
    text-align: center;
}

.btn-navy {
    background-color: var(--navy-dark);
    color: var(--white);
    border: 1px solid var(--navy-dark);
}
.btn-navy:hover {
    background-color: #0b1726;
    border-color: #0b1726;
}

.btn-ghost {
    background: transparent;
    color: var(--white);
    border: 2px solid var(--white);
}
.btn-ghost:hover {
    background: var(--white);
    color: var(--primary-slate);
}

.btn-brochure {
    background-color: rgba(255, 255, 255, 0.15);
    color: var(--white);
    border: 1px solid rgba(255, 255, 255, 0.4);
    backdrop-filter: blur(4px);
}
.btn-brochure:hover {
    background-color: var(--white);
    color: var(--primary-slate);
}

/* --- About & Highlights (Symmetry Layout) --- */
.section-padded {
    padding: 80px 0;
}

.about-header-wrap {
    margin-bottom: 24px;
}
.section-title {
    font-size: 32px;
    font-weight: 800;
    color: var(--primary-slate);
}

.grid-about-symmetry {
    display: grid;
    grid-template-columns: 1.8fr 1.2fr;
    gap: 40px;
    align-items: stretch; /* Stretches both sides to match vertically */
}

.about-text-column {
    display: flex;
    flex-direction: column;
    justify-content: space-between;
}
.about-text-column p {
    margin-bottom: 14px;
    font-size: 15px;
    color: #334155;
    text-align: justify;
    line-height: 1.65;
}
.about-text-column p:last-child {
    margin-bottom: 0;
}

/* Highlights Box - Flush with text column */
.highlights-card {
    background-color: var(--primary-slate);
    background-image: url('../images/adminsys.png');
    background-size: cover;
    background-position: center;
    position: relative;
    color: var(--white);
    padding: 35px 30px;
    border-radius: 4px;
    border: 2px solid #e2e8f0;
    box-shadow: 0 10px 30px rgba(18, 63, 82, 0.2);
    overflow: hidden;
    display: flex;
    flex-direction: column;
    justify-content: space-around;
}

.highlights-card::before {
    content: "";
    position: absolute;
    inset: 0;
    background-color: var(--primary-slate);
    opacity: 0.88;
    z-index: 1;
}

.highlights-inner {
    position: relative;
    z-index: 2;
    display: flex;
    flex-direction: column;
    justify-content: space-between;
    height: 100%;
    gap: 20px;
}

.highlight-item h4 {
    font-size: 17px;
    margin-bottom: 6px;
    color: #ffffff;
    font-weight: 700;
}
.highlight-item p {
    font-size: 14px;
    color: #f8fafc;
    line-height: 1.5;
}

/* --- Statistics Bar --- */
.stats-bar {
    background-color: var(--bg-light);
    padding: 24px 0;
    border-top: 1px solid var(--border-color);
    border-bottom: 1px solid var(--border-color);
}
.stats-grid {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: 16px;
}
.stat-card {
    background-color: var(--accent-purple);
    color: var(--white);
    padding: 18px 12px;
    border-radius: 3px;
    text-align: center;
}
.stat-card .num {
    font-size: 24px;
    font-weight: 800;
    display: block;
}
.stat-card .label {
    font-size: 13px;
    font-weight: 500;
    color: #ffffff;
}

/* --- Scientific Sessions Accordion --- */
.bg-light {
    background-color: var(--bg-light);
}
.text-center {
    text-align: center;
}
.section-subtitle {
    max-width: 820px;
    margin: 10px auto 35px;
    font-size: 15px;
    color: var(--text-muted);
}
.accordion-grid {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 16px;
}
details.session-box {
    background: var(--white);
    border: 1px solid var(--border-color);
    border-radius: 4px;
    overflow: hidden;
    transition: all 0.2s ease;
}
details.session-box summary {
    padding: 16px 20px;
    font-weight: 700;
    font-size: 15px;
    color: var(--navy-dark);
    cursor: pointer;
    list-style: none;
    display: flex;
    justify-content: space-between;
    align-items: center;
}
details.session-box summary::-webkit-details-marker {
    display: none;
}
details.session-box summary::after {
    content: "+";
    font-size: 20px;
    font-weight: bold;
    color: var(--primary-slate);
    transition: transform 0.2s ease;
}
details.session-box[open] summary::after {
    content: "–";
}
details.session-box .session-content {
    padding: 0 20px 16px;
    font-size: 14px;
    color: #475569;
    border-top: 1px solid #f1f5f9;
    padding-top: 12px;
}

/* --- Footer --- */
.site-footer {
    background-color: #1a192b;
    color: #94a3b8;
    padding: 50px 0 25px;
}
.footer-grid {
    display: grid;
    grid-template-columns: 2fr 1fr 1fr;
    gap: 40px;
    margin-bottom: 35px;
}
.footer-col h4 {
    color: var(--white);
    margin-bottom: 14px;
    font-size: 15px;
}
.footer-col ul {
    list-style: none;
}
.footer-col ul li {
    margin-bottom: 8px;
}
.footer-col a {
    color: #94a3b8;
    text-decoration: none;
    font-size: 13px;
    transition: color 0.2s;
}
.footer-col a:hover {
    color: var(--white);
}
.footer-bottom {
    border-top: 1px solid rgba(255, 255, 255, 0.08);
    padding-top: 20px;
    text-align: center;
    font-size: 12px;
}

/* --- Responsive Breakpoints --- */
@media (max-width: 1024px) {
    .header-container {
        flex-direction: column;
        text-align: center;
        gap: 12px;
    }
    .header-center {
        order: 2;
    }
    .header-right {
        order: 3;
    }
}
@media (max-width: 900px) {
    .grid-about-symmetry, .stats-grid, .accordion-grid, .footer-grid {
        grid-template-columns: 1fr;
    }
    .mobile-toggle {
        display: block;
    }
    .main-nav {
        display: none;
        position: absolute;
        top: 100%;
        left: 0;
        width: 100%;
        background: var(--primary-slate);
        border-bottom: 1px solid rgba(255,255,255,0.1);
        padding: 20px;
    }
    .main-nav.active {
        display: block;
    }
    .main-nav ul {
        flex-direction: column;
        align-items: flex-start;
        gap: 12px;
    }
    .hero-content h1 {
        font-size: 30px;
    }
}