/* ===== Math Science SKRU — style ===== */
:root{
  --navy:#0f2a5c; --navy-2:#173a7a; --blue:#2453b3; --gold:#f2b705; --gold-2:#ffd34d;
  --bg:#f6f7fb; --surface:#ffffff; --surface-2:#eef1f8; --text:#16213a; --muted:#5b6782;
  --line:#dde2ee; --shadow:0 6px 24px rgba(15,42,92,.08); --radius:16px;
  --head:"Bai Jamjuree","IBM Plex Sans Thai",sans-serif; --body:"IBM Plex Sans Thai",system-ui,sans-serif;
  color-scheme:light;
}
@media (prefers-color-scheme:dark){
  :root:not([data-theme="light"]){
    --bg:#0b1222; --surface:#121b31; --surface-2:#18233d; --text:#e7ecf7; --muted:#9aa7c3;
    --line:#26324f; --shadow:0 6px 24px rgba(0,0,0,.35); --blue:#7aa2ff; color-scheme:dark;
  }
}
:root[data-theme="dark"]{
  --bg:#0b1222; --surface:#121b31; --surface-2:#18233d; --text:#e7ecf7; --muted:#9aa7c3;
  --line:#26324f; --shadow:0 6px 24px rgba(0,0,0,.35); --blue:#7aa2ff; color-scheme:dark;
}
*{box-sizing:border-box}
html{scroll-behavior:smooth}
body{margin:0;font-family:var(--body);background:var(--bg);color:var(--text);line-height:1.7;font-size:16px}
img{max-width:100%;display:block}
a{color:var(--blue);text-decoration:none}
a:hover{text-decoration:underline}
h1,h2,h3,h4{font-family:var(--head);line-height:1.3;margin:0 0 .5em}
h2{font-size:clamp(1.5rem,3vw,2rem)}
.container{width:min(1160px,100% - 32px);margin-inline:auto}
.skip{position:absolute;left:-999px}.skip:focus{left:16px;top:8px;z-index:99;background:var(--gold);padding:8px 12px;border-radius:8px;color:#000}

/* ---------- header ---------- */
.site-header{position:sticky;top:0;z-index:50;background:rgba(15,42,92,.96);backdrop-filter:blur(8px);color:#fff;box-shadow:0 2px 12px rgba(0,0,0,.15)}
.nav{display:flex;align-items:center;gap:16px;height:68px}
.brand{display:flex;align-items:center;gap:10px;color:#fff;font-family:var(--head);font-weight:700;white-space:nowrap}
.brand:hover{text-decoration:none}
.logo{width:42px;height:42px;border-radius:12px;background:var(--gold);color:var(--navy);display:grid;place-items:center;font-size:24px;font-weight:800;font-family:Georgia,serif}
.brand small{display:block;font-weight:400;font-size:.75rem;opacity:.8;font-family:var(--body)}
.menu{display:flex;gap:4px;margin-left:auto;list-style:none;padding:0;margin-block:0}
.menu a{color:#e6ecff;white-space:nowrap;padding:8px 12px;border-radius:10px;font-size:.95rem;display:block}
.menu a:hover{background:rgba(255,255,255,.1);text-decoration:none}
.menu a[aria-current="page"]{background:var(--gold);color:var(--navy);font-weight:600}
.icon-btn{background:transparent;border:1px solid rgba(255,255,255,.25);color:#fff;width:40px;height:40px;border-radius:10px;cursor:pointer;font-size:18px;display:grid;place-items:center}
.burger{display:none}
@media (max-width:1180px){
  .burger{display:grid;margin-left:auto}
  .menu{position:absolute;top:68px;left:0;right:0;flex-direction:column;background:var(--navy);padding:8px 16px 16px;display:none}
  .menu.open{display:flex}
  .menu a{padding:12px}
}

/* ---------- hero ---------- */
.hero{position:relative;overflow:hidden;background:linear-gradient(135deg,var(--navy) 0%,var(--navy-2) 55%,#2453b3 100%);color:#fff;padding:80px 0 96px}
.hero .container{position:relative;z-index:1;display:grid;grid-template-columns:1.2fr .8fr;gap:40px;align-items:center}
.hero h1{font-size:clamp(2rem,5vw,3.4rem);margin-bottom:.3em}
.hero h1 span{color:var(--gold-2)}
.hero p.lead{font-size:1.15rem;opacity:.92;max-width:40em}
.eyebrow{display:inline-block;background:rgba(242,183,5,.18);color:var(--gold-2);border:1px solid rgba(242,183,5,.4);padding:4px 12px;border-radius:999px;font-size:.85rem;margin-bottom:16px}
.formulas{position:absolute;inset:0;pointer-events:none;opacity:.09;font-family:Georgia,serif;font-size:28px;color:#fff}
.formulas span{position:absolute;white-space:nowrap}
.hero-card{background:rgba(255,255,255,.08);border:1px solid rgba(255,255,255,.18);border-radius:var(--radius);padding:28px;backdrop-filter:blur(4px)}
.hero-card .eq{font-family:Georgia,serif;font-size:clamp(1.6rem,4vw,2.4rem);text-align:center;color:var(--gold-2);margin:8px 0 16px}
.stats{display:grid;grid-template-columns:repeat(3,1fr);gap:12px;text-align:center}
.stats b{display:block;font-family:var(--head);font-size:1.8rem;color:#fff}
.stats small{opacity:.8;font-size:.8rem}
@media (max-width:860px){.hero .container{grid-template-columns:1fr}.hero{padding:56px 0 72px}}

.page-hero{background:linear-gradient(135deg,var(--navy),var(--navy-2));color:#fff;padding:48px 0 40px}
.page-hero h1{font-size:clamp(1.7rem,4vw,2.5rem);margin:0}
.page-hero p{opacity:.85;margin:.4em 0 0}
.crumbs{font-size:.85rem;opacity:.75;margin-bottom:8px}.crumbs a{color:#fff}

/* ---------- buttons ---------- */
.btns{display:flex;flex-wrap:wrap;gap:12px;margin-top:24px}
.btn{display:inline-flex;align-items:center;gap:8px;padding:12px 22px;border-radius:12px;font-weight:600;border:2px solid transparent;cursor:pointer;font-family:var(--body);font-size:1rem;transition:.15s}
.btn:hover{text-decoration:none;transform:translateY(-1px)}
.btn-gold{background:var(--gold);color:var(--navy)}
.btn-gold:hover{background:var(--gold-2)}
.btn-ghost{border-color:rgba(255,255,255,.5);color:#fff}
.btn-ghost:hover{background:rgba(255,255,255,.1)}
.btn-outline{border-color:var(--blue);color:var(--blue);background:transparent}
.btn-sm{padding:8px 14px;font-size:.9rem}

/* ---------- sections & cards ---------- */
section{padding:64px 0}
.section-head{display:flex;justify-content:space-between;align-items:end;gap:16px;margin-bottom:28px;flex-wrap:wrap}
.section-head p{color:var(--muted);margin:0}
.kicker{color:var(--blue);font-weight:600;font-size:.9rem;letter-spacing:.04em}
.alt{background:var(--surface-2)}
.grid{display:grid;gap:20px}
.g2{grid-template-columns:repeat(auto-fit,minmax(min(100%,420px),1fr))}
.g3{grid-template-columns:repeat(auto-fit,minmax(min(100%,300px),1fr))}
.g4{grid-template-columns:repeat(auto-fit,minmax(min(100%,230px),1fr))}
.card{background:var(--surface);border:1px solid var(--line);border-radius:var(--radius);padding:24px;box-shadow:var(--shadow)}
.card h3{font-size:1.15rem}
.card p{color:var(--muted);margin:0}
.feature .ic{width:52px;height:52px;border-radius:14px;background:linear-gradient(135deg,var(--navy),var(--blue));color:var(--gold-2);display:grid;place-items:center;font-size:26px;font-family:Georgia,serif;margin-bottom:14px}
a.card{display:block;color:inherit;transition:.15s}
a.card:hover{text-decoration:none;transform:translateY(-3px);border-color:var(--blue)}

/* news */
.news-item{display:flex;flex-direction:column;gap:8px}
.meta{display:flex;gap:8px;align-items:center;font-size:.85rem;color:var(--muted)}
.tag{background:rgba(242,183,5,.18);color:#8a6400;padding:2px 10px;border-radius:999px;font-weight:600;font-size:.78rem}
:root[data-theme="dark"] .tag{color:var(--gold-2)}
@media (prefers-color-scheme:dark){:root:not([data-theme="light"]) .tag{color:var(--gold-2)}}
.news-item h3{margin:0}
.more{font-weight:600;margin-top:auto}

/* staff */
.toolbar{display:flex;gap:12px;flex-wrap:wrap;margin-bottom:24px}
.input{flex:1;min-width:220px;padding:12px 16px;border-radius:12px;border:1px solid var(--line);background:var(--surface);color:var(--text);font-family:var(--body);font-size:1rem}
.staff-card{text-align:center;padding:28px 20px}
.avatar{width:120px;height:120px;border-radius:50%;margin:0 auto 16px;object-fit:cover;background:linear-gradient(135deg,var(--navy),var(--blue));color:#fff;display:grid;place-items:center;font-family:var(--head);font-size:2.2rem;font-weight:700;border:4px solid var(--surface);box-shadow:0 0 0 3px var(--gold)}
.staff-card h3{font-size:1.05rem;margin-bottom:4px}
.role{display:inline-block;background:var(--gold);color:var(--navy);font-size:.8rem;font-weight:600;padding:2px 10px;border-radius:999px;margin-bottom:8px}
.chips{display:flex;flex-wrap:wrap;gap:6px;justify-content:center;margin-top:8px}
.chip{background:var(--surface-2);border:1px solid var(--line);padding:2px 10px;border-radius:999px;font-size:.8rem;color:var(--muted)}

/* curriculum */
.bar{display:flex;height:22px;border-radius:999px;overflow:hidden;margin:16px 0;background:var(--surface-2)}
.bar span{display:block}
.legend{display:grid;gap:10px}
.legend div{display:flex;justify-content:space-between;gap:12px;align-items:center;border-bottom:1px dashed var(--line);padding-bottom:8px}
.dot{width:12px;height:12px;border-radius:4px;display:inline-block;margin-right:8px;vertical-align:middle}
.list{list-style:none;padding:0;margin:0;display:grid;gap:10px}
.list li{position:relative;padding-left:30px}
.list li::before{content:"✓";position:absolute;left:0;top:0;width:22px;height:22px;border-radius:6px;background:var(--gold);color:var(--navy);display:grid;place-items:center;font-size:.8rem;font-weight:800;margin-top:3px}
.pdf-frame{width:100%;height:75vh;min-height:480px;border:1px solid var(--line);border-radius:var(--radius);background:var(--surface)}
.tabs{display:flex;gap:8px;flex-wrap:wrap;margin-bottom:24px;position:sticky;top:76px;z-index:5}
.tabs a{background:var(--surface);border:1px solid var(--line);padding:8px 16px;border-radius:999px;color:var(--text);font-size:.92rem}
.tabs a:hover{border-color:var(--blue);text-decoration:none}

/* activities */
.act{padding:0;overflow:hidden;display:flex;flex-direction:column}
.act .thumb{aspect-ratio:16/10;background:linear-gradient(135deg,var(--navy),var(--blue));display:grid;place-items:center;color:rgba(255,255,255,.35);font-family:Georgia,serif;font-size:3rem;position:relative}
.act .thumb img{width:100%;height:100%;object-fit:cover}
.act .thumb .yr{position:absolute;top:12px;left:12px;background:var(--gold);color:var(--navy);font-family:var(--head);font-weight:700;font-size:.85rem;padding:2px 10px;border-radius:8px}
.act .body{padding:20px;display:flex;flex-direction:column;gap:6px;flex:1}
.filters{display:flex;gap:8px;flex-wrap:wrap}
.filters button{background:var(--surface);border:1px solid var(--line);color:var(--text);padding:6px 16px;border-radius:999px;cursor:pointer;font-family:var(--body)}
.filters button.on{background:var(--navy);color:#fff;border-color:var(--navy)}

/* links */
.linklist{list-style:none;padding:0;margin:0}
.linklist li{border-bottom:1px solid var(--line)}
.linklist a{display:flex;justify-content:space-between;gap:12px;padding:12px 0;color:var(--text)}
.linklist a::after{content:"↗";color:var(--blue)}
.res .type{font-size:.75rem;font-weight:700;color:var(--blue);text-transform:uppercase;letter-spacing:.06em}

/* contact */
.contact-row{display:flex;gap:14px;align-items:flex-start;padding:14px 0;border-bottom:1px solid var(--line)}
.contact-row .ic{flex:none;width:44px;height:44px;border-radius:12px;background:var(--surface-2);display:grid;place-items:center;font-size:20px}
.map{width:100%;height:100%;min-height:360px;border:0;border-radius:var(--radius)}

/* CTA */
.cta{background:linear-gradient(135deg,var(--gold),var(--gold-2));color:var(--navy);border-radius:24px;padding:40px;display:flex;justify-content:space-between;align-items:center;gap:24px;flex-wrap:wrap}
.cta h2{margin:0}
.cta .btn{background:var(--navy);color:#fff}

/* footer */
.site-footer{background:#0a1b3d;color:#c7d1ea;padding:48px 0 24px;margin-top:0}
.site-footer a{color:#fff}
.site-footer h4{color:#fff;font-size:1rem}
.foot-grid{display:grid;grid-template-columns:1.4fr 1fr 1fr;gap:32px}
.foot-grid ul{list-style:none;padding:0;margin:0;display:grid;gap:6px;font-size:.92rem}
.copy{border-top:1px solid rgba(255,255,255,.1);margin-top:32px;padding-top:16px;font-size:.85rem;opacity:.7;display:flex;justify-content:space-between;flex-wrap:wrap;gap:8px}
@media (max-width:760px){.foot-grid{grid-template-columns:1fr}}

/* sudoku */
.sudoku-wrap{display:grid;grid-template-columns:auto 1fr;gap:32px;align-items:start}
@media (max-width:820px){.sudoku-wrap{grid-template-columns:1fr}}
.board{display:grid;grid-template-columns:repeat(9,1fr);width:min(468px,100%);aspect-ratio:1;border:3px solid var(--navy);border-radius:10px;overflow:hidden;background:var(--surface);user-select:none}
:root[data-theme="dark"] .board{border-color:var(--gold)}
.cell{display:grid;place-items:center;font-family:var(--head);font-size:clamp(1rem,4.5vw,1.6rem);border-right:1px solid var(--line);border-bottom:1px solid var(--line);cursor:pointer;color:var(--blue);font-weight:600}
.cell.given{color:var(--text);font-weight:700;cursor:default}
.cell:nth-child(9n+3),.cell:nth-child(9n+6){border-right:2px solid var(--navy)}
.cell:nth-child(n+19):nth-child(-n+27),.cell:nth-child(n+46):nth-child(-n+54){border-bottom:2px solid var(--navy)}
.cell.peer{background:var(--surface-2)}
.cell.same{background:rgba(242,183,5,.25)}
.cell.sel{background:rgba(36,83,179,.25)}
.cell.err{color:#d93025;background:rgba(217,48,37,.12)}
.pad{display:grid;grid-template-columns:repeat(5,1fr);gap:8px;margin-top:16px;width:min(468px,100%)}
.pad button{padding:12px 0;border-radius:10px;border:1px solid var(--line);background:var(--surface);color:var(--text);font-family:var(--head);font-size:1.2rem;cursor:pointer}
.pad button:hover{border-color:var(--blue)}
select.input{flex:0 0 auto;min-width:0}
.win{background:var(--gold);color:var(--navy);padding:12px 16px;border-radius:12px;font-weight:600;display:none}
.win.show{display:block}

/* ===== v2: auth, modal, forms, tables, admin ===== */
.muted{color:var(--muted)}
.logo-img{width:46px;height:46px;border-radius:50%;background:#fff;object-fit:contain;flex:none}
.demo-bar{background:#fff4cc;color:#5a4300;font-size:.85rem;text-align:center;padding:6px 16px}
.demo-bar button{margin-left:8px;border:1px solid #c9a227;background:transparent;border-radius:6px;padding:2px 8px;cursor:pointer;color:inherit;font-family:inherit}
.menu-auth{margin-left:8px;display:flex;align-items:center}
.user-chip{display:flex;align-items:center;gap:8px;font-size:.88rem;color:#e6ecff}
.user-chip>span{max-width:160px;overflow:hidden;text-overflow:ellipsis;white-space:nowrap}
.menu .btn{padding:6px 12px}
.menu .btn-gold{color:var(--navy)}
@media (max-width:420px){.brand small{display:none}}
@media (max-width:1180px){.menu-auth{margin:8px 0 0}.user-chip{flex-wrap:wrap}}
.user-chip .btn-ghost{color:#fff;background:transparent}
.news-img{width:100%;aspect-ratio:16/9;object-fit:cover;border-radius:10px}
a.staff-card{display:flex;flex-direction:column;align-items:center}

#toasts{position:fixed;right:16px;bottom:16px;z-index:200;display:grid;gap:8px;max-width:min(380px,calc(100% - 32px))}
.toast{background:var(--navy);color:#fff;padding:12px 16px;border-radius:12px;box-shadow:var(--shadow);animation:pop .2s}
.toast.err{background:#b3261e}
@keyframes pop{from{transform:translateY(8px);opacity:0}}

dialog.modal{border:0;border-radius:var(--radius);padding:28px;width:min(560px,calc(100% - 32px));max-height:calc(100vh - 48px);background:var(--surface);color:var(--text);box-shadow:0 24px 64px rgba(0,0,0,.35)}
dialog.modal.wide{width:min(860px,calc(100% - 32px))}
dialog.modal::backdrop{background:rgba(8,16,36,.55)}
.modal-x{position:absolute;top:12px;right:12px;width:36px;height:36px;border-radius:10px;border:1px solid var(--line);background:var(--surface);color:var(--text);font-size:20px;cursor:pointer}

.form{display:grid;gap:14px}
.form label{display:grid;gap:6px;font-weight:500;font-size:.92rem}
.form .row2{display:grid;grid-template-columns:1fr 1fr;gap:12px}
@media (max-width:560px){.form .row2{grid-template-columns:1fr}}
.form input,.form select,.form textarea{padding:10px 12px;border-radius:10px;border:1px solid var(--line);background:var(--bg);color:var(--text);font-family:var(--body);font-size:1rem;width:100%}
.form textarea{min-height:110px;resize:vertical}
.form .check{display:flex;align-items:center;gap:8px;font-weight:400}
.form .check input{width:auto}
.form .hint{font-weight:400;color:var(--muted);font-size:.82rem}
.form-actions{display:flex;gap:10px;justify-content:flex-end;flex-wrap:wrap;margin-top:6px}
.img-prev{max-width:140px;max-height:140px;border-radius:10px;border:1px solid var(--line);object-fit:cover}

.table-wrap{overflow-x:auto;border:1px solid var(--line);border-radius:var(--radius);background:var(--surface)}
table.tbl{width:100%;border-collapse:collapse;font-size:.92rem}
.tbl th,.tbl td{padding:10px 12px;text-align:left;border-bottom:1px solid var(--line);vertical-align:top}
.tbl th{background:var(--surface-2);font-weight:600;white-space:nowrap;position:sticky;top:0}
.tbl tr:last-child td{border-bottom:0}
.tbl td.actions{white-space:nowrap;text-align:right}
.badge{display:inline-block;padding:2px 10px;border-radius:999px;font-size:.78rem;font-weight:600;background:var(--surface-2);color:var(--muted);white-space:nowrap}
.badge.pending{background:#fff1c2;color:#7a5a00}
.badge.approved,.badge.open{background:#d7f5df;color:#14612c}
.badge.rejected,.badge.full{background:#fde0dd;color:#9b1c13}
.badge.cancelled{background:var(--surface-2);color:var(--muted);text-decoration:line-through}
.btn-danger{background:#b3261e;color:#fff}
.btn-light{background:var(--surface-2);color:var(--text);border-color:var(--line)}
.link-btn{background:none;border:0;color:var(--blue);cursor:pointer;font:inherit;padding:4px 6px}
.link-btn.danger{color:#b3261e}

/* staff detail */
.profile-head{display:grid;grid-template-columns:auto 1fr;gap:32px;align-items:center}
.profile-head .avatar{width:180px;height:180px;font-size:3rem;margin:0}
@media (max-width:640px){.profile-head{grid-template-columns:1fr;text-align:center}.profile-head .avatar{margin:0 auto}}
.pub{padding:14px 0;border-bottom:1px solid var(--line)}
.pub:last-child{border-bottom:0}
.pub .yr{font-family:var(--head);font-weight:700;color:var(--blue);margin-right:8px}

/* seminars & booking */
.sem-item{display:grid;grid-template-columns:auto 1fr auto;gap:16px;align-items:start;padding:16px 0;border-bottom:1px solid var(--line)}
.sem-item:last-child{border-bottom:0}
.sem-term{font-family:var(--head);font-weight:700;background:var(--navy);color:#fff;border-radius:10px;padding:4px 10px;font-size:.85rem;white-space:nowrap}
.sem-item h3{font-size:1.02rem;margin:0 0 4px}
@media (max-width:640px){.sem-item{grid-template-columns:1fr}}
.topic{display:flex;flex-direction:column;gap:8px}
.topic .foot{display:flex;justify-content:space-between;align-items:center;gap:8px;margin-top:auto;padding-top:8px;flex-wrap:wrap}
.notice{background:var(--surface-2);border-left:4px solid var(--gold);padding:14px 18px;border-radius:10px}

/* admin */
.admin{display:grid;grid-template-columns:240px 1fr;min-height:calc(100vh - 68px)}
.admin-side{background:var(--surface);border-right:1px solid var(--line);padding:20px 12px;position:sticky;top:68px;height:calc(100vh - 68px);overflow:auto}
.admin-side button{display:flex;width:100%;gap:10px;align-items:center;padding:10px 12px;border:0;border-radius:10px;background:transparent;color:var(--text);font-family:var(--body);font-size:.95rem;cursor:pointer;text-align:left}
.admin-side button:hover{background:var(--surface-2)}
.admin-side button.on{background:var(--navy);color:#fff}
.admin-side .grp{font-size:.75rem;color:var(--muted);text-transform:uppercase;letter-spacing:.08em;margin:16px 12px 6px}
.admin-main{padding:28px;min-width:0}
.admin-top{display:flex;justify-content:space-between;align-items:center;gap:12px;flex-wrap:wrap;margin-bottom:18px}
.admin-top h1{font-size:1.5rem;margin:0}
.kpis{display:grid;grid-template-columns:repeat(auto-fit,minmax(170px,1fr));gap:14px;margin-bottom:24px}
.kpi{background:var(--surface);border:1px solid var(--line);border-radius:14px;padding:16px}
.kpi b{display:block;font-family:var(--head);font-size:1.8rem}
.kpi span{color:var(--muted);font-size:.88rem}
@media (max-width:860px){.admin{grid-template-columns:1fr}.admin-side{position:static;height:auto;display:flex;flex-wrap:wrap;gap:4px;border-right:0;border-bottom:1px solid var(--line)}.admin-side button{width:auto}.admin-side .grp{display:none}.admin-main{padding:20px 16px}}
.gate{max-width:480px;margin:80px auto;text-align:center}
.avatar.mini{width:40px;height:40px;font-size:.9rem;margin:0;border-width:2px;box-shadow:0 0 0 2px var(--gold)}
.thumb-mini{width:64px;height:40px;object-fit:cover;border-radius:6px}