:root {
    --primary: #2f5aae;
    --primary-dark: #1f3f80;
    --accent: #dd3333;
    --text: #2d2d2d;
    --muted: #505050;
    --border: #e5e7eb;
    --bg: #ffffff;
    --bg-soft: #f5f7fb;
}

* { box-sizing: border-box; }

body {
    margin: 0;
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
    font-size: 16px;
    line-height: 1.7;
    color: var(--text);
    background: var(--bg);
}

a { color: var(--primary); text-decoration: none; }
a:hover { text-decoration: underline; }
img { max-width: 100%; height: auto; }

.container { max-width: 1170px; margin: 0 auto; padding: 0 16px; }

.skip-link { position: absolute; left: -9999px; }
.skip-link:focus { left: 10px; top: 10px; background: #fff; padding: 8px 12px; z-index: 1000; }

/* ---------- Header ---------- */
.site-header {
    background: #fff;
    border-bottom: 1px solid var(--border);
    position: sticky;
    top: 0;
    z-index: 100;
}
.header-inner {
    display: flex;
    align-items: center;
    gap: 24px;
    min-height: 90px;
    position: relative;
}
.brand img { display: block; max-height: 70px; width: auto; }

.main-nav { margin-left: auto; }
.nav-ul, .sub-menu { list-style: none; margin: 0; padding: 0; }
.nav-ul { display: flex; flex-wrap: wrap; gap: 4px; }
.nav-ul > li { position: relative; }
.nav-ul .wrap { display: flex; align-items: center; }
.nav-ul > li > .wrap > a {
    display: block;
    padding: 10px 8px;
    color: #000;
    font-weight: 600;
    font-size: 14px;
    text-transform: uppercase;
    white-space: nowrap;
}
.nav-ul > li.active > .wrap > a,
.nav-ul > li > .wrap > a:hover { color: var(--primary); text-decoration: none; }

.sub-toggle {
    border: 0; background: none; cursor: pointer;
    font-size: 12px; color: #000; padding: 4px;
}

.sub-menu {
    position: absolute;
    top: 100%;
    left: 0;
    min-width: 240px;
    background: #fff;
    box-shadow: 0 8px 24px rgba(0,0,0,.12);
    border-top: 3px solid var(--primary);
    opacity: 0;
    visibility: hidden;
    transform: translateY(8px);
    transition: .2s;
    z-index: 50;
}
.nav-ul li:hover > .sub-menu,
.nav-ul li:focus-within > .sub-menu { opacity: 1; visibility: visible; transform: none; }
.sub-menu a {
    display: block;
    padding: 9px 16px;
    color: var(--text);
    font-size: 14px;
    border-bottom: 1px solid #f1f1f1;
}
.sub-menu li.active a,
.sub-menu a:hover { background: var(--bg-soft); color: var(--primary); text-decoration: none; }

.language-switch { display: flex; gap: 8px; align-items: center; }
.language-switch img { width: 28px; height: 18px; object-fit: cover; border: 1px solid #ddd; display: block; }

.nav-toggle {
    display: none;
    margin-left: auto;
    border: 1px solid var(--border);
    background: #fff;
    padding: 10px;
    cursor: pointer;
    border-radius: 4px;
}
.nav-toggle span { display: block; width: 22px; height: 2px; background: #000; margin: 4px 0; }

/* ---------- Content ---------- */
.site-content { padding: 40px 0 60px; min-height: 60vh; }
.page-title {
    font-size: 30px;
    margin: 0 0 24px;
    padding-bottom: 12px;
    border-bottom: 3px solid var(--primary);
    display: inline-block;
}
.entry h2 { color: var(--primary-dark); }
.entry p { text-align: justify; }

/* Ana sayfa: afişler → logo bandı → davet metni (orijinal sıralama) */
.home { max-width: 940px; margin: 0 auto; }

.posters {
    display: flex;
    justify-content: space-between;
    flex-wrap: wrap;
    gap: 20px;
    margin-bottom: 20px;
}
.posters a { flex: 0 1 439px; }
.posters img { display: block; width: 100%; height: auto; }

.hero-logos { margin-bottom: 20px; }
.hero-logos img { display: block; width: 100%; height: auto; }

.invite {
    text-align: center;
    background: var(--bg-soft);
    border: 1px solid var(--border);
    border-top: 4px solid var(--primary);
    border-radius: 6px;
    padding: 28px 32px;
    box-shadow: 0 4px 16px rgba(0,0,0,.06);
}
@media (max-width: 600px) {
    .invite { padding: 20px 16px; }
}
.invite-title { color: #ff0000; font-weight: 700; font-size: 22px; margin: 10px 0 20px; }
.invite p { margin: 0 0 1.2em; }

@media (max-width: 900px) {
    .posters { justify-content: center; }
}

.program-link { text-align: center; padding: 30px 0; }
.program-link a { color: #ff0000; }

/* Davetli konuşmacılar: 1 afiş üstte ortada, 2 afiş altta sol/sağ */
.speaker-posters {
    max-width: 940px;
    margin: 0 auto;
    display: flex;
    flex-wrap: wrap;
    justify-content: space-between;
    gap: 20px;
}
.speaker-posters a { flex: 0 1 450px; }
.speaker-posters a:first-child { flex-basis: 100%; }
.speaker-posters a:first-child img { width: 450px; margin: 0 auto; }
.speaker-posters img { display: block; width: 100%; max-width: 100%; height: auto; }
@media (max-width: 960px) {
    .speaker-posters { justify-content: center; }
}

.info-cards {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
    gap: 16px;
    margin: 30px 0;
}
.info-card {
    border: 1px solid var(--border);
    border-top: 4px solid var(--primary);
    padding: 18px;
    border-radius: 4px;
    background: #fff;
}
.info-card strong { display: block; font-size: 18px; color: var(--primary-dark); }

table.dates { width: 100%; border-collapse: collapse; }
table.dates th, table.dates td { border: 1px solid var(--border); padding: 12px 14px; text-align: left; }
table.dates th { background: var(--primary); color: #fff; }
table.dates tr:nth-child(even) td { background: var(--bg-soft); }
table.dates tr.highlight td { font-weight: 700; color: var(--accent); }

.topics {
    list-style: none; padding: 0;
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(220px, 1fr));
    gap: 8px;
}
.topics li { background: var(--bg-soft); padding: 8px 12px; border-left: 3px solid var(--primary); font-weight: 600; font-size: 14px; }

/* Kurullar */
.committee { columns: 2; column-gap: 40px; padding-left: 1.4em; margin: 0; }
.committee li { break-inside: avoid; padding: 4px 0; border-bottom: 1px dashed var(--border); font-size: 15px; }
.committee-note { margin-top: 20px; font-style: italic; color: var(--muted); }
@media (max-width: 800px) { .committee { columns: 1; } }


/* Anahtar-değer tabloları (yazım formatı, banka bilgileri) */
table.format-table { max-width: 640px; margin: 16px 0; }
table.format-table th { width: 40%; }

.journal-list li { padding: 4px 0; }
.program-heading { text-align: center; }

/* Foto galeri albümleri */
.albums { display: grid; grid-template-columns: repeat(auto-fill, minmax(280px, 1fr)); gap: 20px; }
.album { display: block; border: 1px solid var(--border); border-radius: 6px; overflow: hidden; color: var(--text); background: #fff; }
.album:hover { text-decoration: none; box-shadow: 0 6px 20px rgba(0,0,0,.12); }
.album img { display: block; width: 100%; height: 220px; object-fit: cover; }
.album span { display: block; padding: 12px 14px; font-weight: 700; }
.album small { font-weight: 400; color: var(--muted); }

.notice { background: #fff8e1; border: 1px solid #ffe08a; padding: 14px 18px; border-radius: 4px; }

.map { width: 100%; height: 400px; border: 0; margin-top: 20px; }

.gallery { display: grid; grid-template-columns: repeat(auto-fill, minmax(220px, 1fr)); gap: 12px; }
.gallery img { width: 100%; height: 180px; object-fit: cover; border-radius: 4px; }

/* ---------- Footer ---------- */
.site-footer { background: #24292e; color: #ccc; padding: 30px 0; font-size: 14px; }
.site-footer a { color: #fff; }
.footer-inner { text-align: center; }
.site-footer .copy { color: #8c8c8c; margin-bottom: 0; }

/* ---------- Popup ---------- */
.popup-overlay {
    position: fixed; inset: 0;
    background: rgba(0,0,0,.6);
    display: flex; align-items: center; justify-content: center;
    z-index: 2000; padding: 16px;
}
.popup-overlay[hidden] { display: none; }
.popup {
    background: #fff; max-width: 1280px; width: 100%;
    max-height: 90vh; overflow: auto;
    padding: 28px; border-radius: 6px; position: relative;
    text-align: center;
}
.popup .signature { text-align: center; }
.popup h3 { margin-top: 0; color: var(--primary-dark); }
.popup-close {
    position: absolute; top: 8px; right: 12px;
    border: 0; background: none; font-size: 28px; cursor: pointer; line-height: 1;
}

/* ---------- Mobile ---------- */
@media (max-width: 1100px) {
    .nav-toggle { display: block; }
    .language-switch { position: absolute; right: 70px; top: 50%; transform: translateY(-50%); }
    .main-nav {
        position: fixed; top: 0; left: 0; bottom: 0;
        width: 300px; max-width: 85%;
        background: #fff;
        box-shadow: 2px 0 16px rgba(0,0,0,.2);
        transform: translateX(-100%);
        transition: transform .25s;
        overflow-y: auto;
        padding: 60px 0 20px;
        margin: 0;
        z-index: 200;
    }
    body.menu-open .main-nav { transform: none; }
    .nav-ul { flex-direction: column; }
    .nav-ul .wrap { justify-content: space-between; padding: 0 16px; border-bottom: 1px solid #f1f1f1; }
    .sub-menu {
        position: static; opacity: 1; visibility: visible; transform: none;
        box-shadow: none; border-top: 0; display: none; min-width: 0;
    }
    .nav-ul li.open > .sub-menu { display: block; }
    .nav-ul li:hover > .sub-menu { display: none; }
    .nav-ul li.open:hover > .sub-menu { display: block; }
    .sub-menu a { padding-left: 32px; }
}

/* Kayıt sayfası: orijinaldeki gibi sade metin */
.registration p { text-align: left; margin: 0 0 1em; }
.registration h3 { margin: 0 0 1em; }