:root{
  /* โทนสีจากแบนเนอร์ Research Expo 2026 (เขียว-ม่วง-ทอง-ส้ม) */
  --navy:#0e4423; --navy2:#1c7c3c; --navy3:#2e9e4f;        /* เดิมน้ำเงิน -> ใช้เป็นเขียวเข้มสำหรับพื้นเข้ม/หัวข้อ */
  --green1:#3aa655; --green2:#2e9e4f; --green-grad:linear-gradient(90deg,#2e9e4f,#15803a);
  --gold:#f4c430; --gold2:#e0a31e; --amber:#e8821e; --orange:#e8821e;
  --purple:#6b4a9e; --cyan:#6b4a9e;                          /* repurpose cyan -> ม่วง */
  --ink:#1d2a20; --muted:#5e6b60; --line:#e2ebe3; --bg:#f3f8f3;
  --radius:14px; --shadow:0 8px 30px rgba(14,68,35,.12);
}
*{box-sizing:border-box;margin:0;padding:0}
body{font-family:'Kanit',sans-serif;color:var(--ink);background:var(--bg);line-height:1.65}
a{text-decoration:none;color:inherit}
.container{width:100%;max-width:100%;margin:0 auto;padding:0 40px}
img{max-width:100%;display:block}

/* ---------- Header ---------- */
.site-header{position:sticky;top:0;z-index:50}
.topbar{background:var(--navy);color:#dff0e4;font-size:.82rem}
.topbar-inner{display:flex;justify-content:space-between;padding:6px 18px}
.navbar{background:#fff;box-shadow:var(--shadow);border-bottom:3px solid var(--green2)}
.navbar-inner{display:flex;align-items:center;justify-content:space-between;min-height:64px}
.brand{display:flex;flex-direction:column;line-height:1}
.brand-isan{font-weight:700;font-size:1.7rem;background:var(--green-grad);-webkit-background-clip:text;background-clip:text;color:transparent;letter-spacing:1px}
.brand-sub{color:var(--navy2);font-size:.72rem;letter-spacing:1px}
.brand-sub b{color:var(--gold2)}
.menu{display:flex;align-items:center;gap:4px;list-style:none}
.menu a{color:#27402e;padding:10px 14px;border-radius:8px;font-weight:400;font-size:.97rem;transition:.2s}
.menu a:hover{background:#eef7f0;color:var(--navy2)}
.menu a.active{color:var(--navy3);font-weight:600}
.btn-nav{background:var(--green-grad);color:#06351a !important;font-weight:600 !important;border-radius:30px !important}
.btn-nav.active{color:#06351a !important}
.navtoggle,.navtoggle-label{display:none}

/* navbar แบบโปร่งใส วางทับมุมขวาบนของแบนเนอร์ (หน้าแรก) */
.site-header.overlay{position:absolute;top:0;left:0;right:0;z-index:30;background:transparent}
.site-header.overlay .navbar{background:transparent;box-shadow:none;border-bottom:none}
.site-header.overlay .navbar-inner{justify-content:flex-end;gap:8px;min-height:60px;padding-top:8px}
.site-header.overlay .brand{display:none}
/* เมนูเด่น: พิลล์พื้นขาวมีเงา */
.site-header.overlay .menu{margin-left:auto;background:rgba(255,255,255,.96);border:1px solid rgba(46,158,79,.25);
  border-radius:30px;padding:5px 7px;gap:3px;box-shadow:0 6px 22px rgba(14,68,35,.22)}
.site-header.overlay .menu a{color:var(--navy2);font-weight:600}
.site-header.overlay .menu a:hover{background:#e9f6ee;color:var(--navy3)}
/* ให้ "หน้าแรก" (active) และ "ลงทะเบียน ฟรี!" (btn-nav) เป็นลิงก์ธรรมดาเหมือนเมนูอื่น */
.site-header.overlay .menu a.active{background:transparent;color:var(--navy2)}
.site-header.overlay .menu a.btn-nav{background:transparent !important;color:var(--navy2) !important;
  font-weight:600 !important;border-radius:8px !important;padding:10px 14px !important}
.site-header.overlay .menu a.btn-nav:hover{background:#e9f6ee !important;color:var(--navy3) !important}

/* ---------- Banner ---------- */
.hero-banner{padding:0;background:var(--navy);position:relative}
.hero-banner img{width:100%;height:auto;display:block;margin:0 auto;max-width:1600px}
.banner-slides{position:relative;max-width:1600px;margin:0 auto}
.banner-slide{display:none}
.banner-slide.active{display:block;animation:bfade .6s ease}
.banner-slides[data-count="1"] .banner-slide{display:block}
@keyframes bfade{from{opacity:.3}to{opacity:1}}
.banner-dots{position:absolute;bottom:14px;left:50%;transform:translateX(-50%);display:flex;gap:8px;z-index:5}
.banner-dots .bdot{width:11px;height:11px;border-radius:50%;background:rgba(255,255,255,.6);border:1px solid rgba(0,0,0,.15);cursor:pointer}
.banner-dots .bdot.active{background:var(--gold)}
/* language switch */
.lang-switch{display:flex;align-items:center;gap:4px;margin-left:6px}
.lang-switch a{padding:4px 7px !important;border-radius:6px;font-size:.85rem;color:var(--muted)}
.lang-switch a.on{background:var(--green-grad);color:#06351a;font-weight:600}
.site-header.overlay .lang-switch a{color:var(--navy2)}
.site-header.overlay .lang-switch a.on{color:#06351a}
.hero-overlay{position:absolute;left:50%;bottom:calc(8% + 0.2in);transform:translateX(-50%);
  display:flex;gap:16px;justify-content:center;flex-wrap:wrap;padding:0 16px;width:100%;max-width:760px}
.hero-overlay .btn{box-shadow:0 6px 18px rgba(14,68,35,.25);padding:15.6px 36px;font-size:1.2rem}
.btn-outline-green{background:rgba(255,255,255,.9);border:2px solid var(--green2);color:var(--navy2)}
.btn-outline-green:hover{background:#fff;transform:translateY(-2px)}

/* ---------- Hero (legacy text hero) ---------- */
.hero{position:relative;background:linear-gradient(120deg,#1c7c3c 0%,#2e9e4f 60%,#3aa655 100%);color:#fff;overflow:hidden}
.hero::after{content:"";position:absolute;right:-80px;top:-80px;width:380px;height:380px;background:radial-gradient(circle,rgba(41,171,226,.35),transparent 70%)}
.hero-inner{position:relative;z-index:2;padding:54px 0 60px;text-align:center}
.hero .badge{display:inline-block;background:rgba(255,255,255,.12);border:1px solid rgba(255,255,255,.25);padding:6px 18px;border-radius:30px;font-size:.9rem;margin-bottom:18px}
.hero h1{font-size:2.9rem;line-height:1.1;margin-bottom:6px}
.hero h1 .g{background:var(--green-grad);-webkit-background-clip:text;background-clip:text;color:transparent}
.hero .th{font-size:1.5rem;font-weight:500;margin-bottom:14px}
.hero .th .y{color:var(--gold)}
.hero .concept{max-width:760px;margin:0 auto 22px;color:#dbe6ff}
.hero .meta{display:flex;gap:26px;justify-content:center;flex-wrap:wrap;margin-bottom:26px;font-size:1.02rem}
.hero .meta span{background:rgba(255,255,255,.08);padding:8px 18px;border-radius:10px}
.hero .cta{display:inline-flex;gap:14px;flex-wrap:wrap;justify-content:center}
.btn{display:inline-block;padding:13px 30px;border-radius:30px;font-weight:600;cursor:pointer;border:none;font-family:inherit;font-size:1rem;transition:.2s}
.btn-gold{background:linear-gradient(90deg,var(--gold),var(--gold2));color:#3a2700}
.btn-gold:hover{filter:brightness(1.08);transform:translateY(-2px)}
.btn-outline{background:transparent;border:2px solid rgba(255,255,255,.6);color:#fff}
.btn-outline:hover{background:rgba(255,255,255,.12)}
.btn-green{background:var(--green-grad);color:#06351a}
.btn-green:hover{filter:brightness(1.06);transform:translateY(-2px)}
.btn-cyan{background:linear-gradient(90deg,#f4a01e,#e8821e);color:#fff}
.btn-cyan:hover{filter:brightness(1.08);transform:translateY(-2px)}

/* ---------- Sections ---------- */
section{padding:30px 0}
.section-head{text-align:center;margin-bottom:20px}
.section-head h2{font-size:1.8rem;color:var(--navy2)}
.section-head h2 .g{background:var(--green-grad);-webkit-background-clip:text;background-clip:text;color:transparent}
.section-head p{color:var(--muted)}
.section-head::after{content:"";display:block;width:64px;height:4px;background:var(--green-grad);border-radius:4px;margin:8px auto 0}

/* section พื้นหลังเข้ม (ตามชุดสี) */
.sec-dark{background:linear-gradient(120deg,var(--navy) 0%,var(--navy2) 100%)}
.sec-dark .section-head h2{color:#fff}
.sec-dark .section-head h2 .g{background:linear-gradient(90deg,#ffe9a8,var(--gold));-webkit-background-clip:text;background-clip:text;color:transparent}
.sec-dark .section-head p{color:rgba(255,255,255,.85)}

/* features */
.features{display:grid;grid-template-columns:repeat(4,1fr);gap:14px}
.features.feat6{grid-template-columns:repeat(3,1fr)}
.feature{background:#fff;border-radius:var(--radius);padding:18px 14px;text-align:center;box-shadow:var(--shadow);border-top:4px solid var(--green2);transition:.2s}
.feature:hover{transform:translateY(-5px)}
.feature .ic{font-size:2rem;margin-bottom:8px}
.feature h3{font-size:1.05rem;color:var(--navy2);margin-bottom:4px}
.feature p{font-size:.85rem;color:var(--muted)}

/* news grid */
.news-grid{display:grid;grid-template-columns:repeat(3,1fr);gap:16px}
.news-card{background:rgba(255,255,255,.85);border-radius:var(--radius);overflow:hidden;box-shadow:var(--shadow);display:flex;flex-direction:column;transition:.2s}
.news-card:hover{transform:translateY(-5px)}
.news-card .thumb{height:180px;background:linear-gradient(135deg,#2e9e4f,#1c7c3c);display:flex;align-items:center;justify-content:center;color:#fff;font-size:2.6rem}
.news-card .thumb img{width:100%;height:100%;object-fit:cover}
.news-card .body{padding:18px;display:flex;flex-direction:column;flex:1}
.tag{align-self:flex-start;background:#e8f6ec;color:var(--green2);font-size:.74rem;padding:3px 12px;border-radius:20px;font-weight:500;margin-bottom:10px}
.news-card h3{font-size:1.08rem;color:var(--navy2);margin-bottom:8px;line-height:1.35}
.news-card p{font-size:.9rem;color:var(--muted);flex:1}
.news-card .meta{font-size:.78rem;color:#9aa3b8;margin-top:12px;display:flex;justify-content:space-between}
.center{text-align:center;margin-top:20px}

/* news-card สีเขียว (หน้าแรก) — พื้นเขียว ตัวอักษรขาว */
.news-green .news-card{background:var(--navy);border:2px solid var(--green2)}
.news-green .news-card h3,
.news-green .news-card h3 a{color:#fff}
.news-green .news-card p{color:rgba(255,255,255,.9)}
.news-green .news-card .meta{color:rgba(255,255,255,.72)}
.news-green .news-card .tag{background:rgba(255,255,255,.22);color:#fff}
.news-green .news-card .thumb{background:rgba(0,0,0,.12)}

/* register choice */
.reg-cards{display:grid;grid-template-columns:repeat(2,1fr);gap:18px;max-width:880px;margin:0 auto}
.reg-cards-3{grid-template-columns:repeat(3,1fr);max-width:1060px}
.reg-card{background:#fff;border-radius:18px;padding:26px 26px;text-align:center;box-shadow:var(--shadow);border:2px solid transparent;transition:.2s}
.reg-card:hover{border-color:var(--green2);transform:translateY(-5px)}
.reg-card .ic{font-size:3rem;margin-bottom:14px}
.reg-card h3{color:var(--navy2);font-size:1.35rem;margin-bottom:10px}
.reg-card p{color:var(--muted);margin-bottom:22px;min-height:70px}

/* forms */
.form-wrap{max-width:760px;margin:0 auto;background:#fff;border-radius:18px;box-shadow:var(--shadow);overflow:hidden}
.form-head{background:linear-gradient(120deg,var(--navy2),var(--navy3));color:#fff;padding:26px 30px}
.form-head h2{font-size:1.5rem}
.form-head p{color:#dff3e6;font-size:.92rem}
.form-body{padding:30px}
.form-row{display:grid;grid-template-columns:1fr 1fr;gap:18px}
.field{margin-bottom:18px}
.field.full{grid-column:1/-1}
label{display:block;font-size:.92rem;font-weight:500;margin-bottom:6px;color:var(--ink)}
label .req{color:#e6492d}
input,select,textarea{width:100%;padding:11px 13px;border:1.5px solid var(--line);border-radius:10px;font-family:inherit;font-size:.96rem;background:#fbfcff;transition:.15s}
input:focus,select:focus,textarea:focus{outline:none;border-color:var(--green2);background:#fff;box-shadow:0 0 0 3px rgba(57,181,74,.12)}
textarea{resize:vertical;min-height:100px}
.form-actions{margin-top:8px;display:flex;gap:12px;align-items:center}
.hint{font-size:.82rem;color:var(--muted);margin-top:4px}

/* flash & alerts */
.flash{padding:13px 18px;border-radius:10px;margin:18px 0;font-weight:500}
.flash-success{background:#e8f6ec;color:#1c7a32;border:1px solid #b7e3c2}
.flash-error{background:#fdecea;color:#b8311c;border:1px solid #f4c4bc}
.errors{background:#fdecea;color:#b8311c;border:1px solid #f4c4bc;border-radius:10px;padding:12px 18px;margin-bottom:18px}
.errors ul{margin-left:18px}

/* stats */
.stat-cards{display:grid;grid-template-columns:repeat(4,1fr);gap:14px;margin-bottom:22px}
.stat-card{background:#fff;border-radius:16px;padding:18px 20px;box-shadow:var(--shadow);position:relative;overflow:hidden}
.stat-card .num{font-size:2.4rem;font-weight:700;color:var(--navy2)}
.stat-card .lbl{color:var(--muted);font-size:.95rem}
.stat-card .ic{position:absolute;right:16px;top:14px;font-size:2rem;opacity:.25}
.stat-card.green{border-left:5px solid var(--green2)}
.stat-card.gold{border-left:5px solid var(--gold2)}
.stat-card.cyan{border-left:5px solid var(--cyan)}
.stat-card.navy{border-left:5px solid var(--navy3)}
.chart-grid{display:grid;grid-template-columns:1fr 1fr;gap:16px}
.panel{background:#fff;border-radius:16px;padding:20px;box-shadow:var(--shadow)}
.panel h3{color:var(--navy2);margin-bottom:14px;font-size:1.15rem}
.bar-row{margin-bottom:11px}
.bar-row .bl{display:flex;justify-content:space-between;font-size:.9rem;margin-bottom:5px}
.bar-track{background:#eef2f9;border-radius:20px;height:14px;overflow:hidden}
.bar-fill{height:100%;border-radius:20px;background:var(--green-grad)}
.bar-fill.cyan{background:linear-gradient(90deg,#7d5ba6,#5a3d87)}
.bar-fill.gold{background:linear-gradient(90deg,#f4c430,#e0a31e)}

/* tables */
.table-wrap{overflow-x:auto;background:#fff;border-radius:14px;box-shadow:var(--shadow)}
table.data{width:100%;border-collapse:collapse;font-size:.92rem}
table.data th,table.data td{padding:12px 14px;text-align:left;border-bottom:1px solid var(--line)}
table.data th{background:var(--navy2);color:#fff;font-weight:500;white-space:nowrap}
table.data tr:hover td{background:#f7faff}
.badge{display:inline-block;padding:3px 11px;border-radius:20px;font-size:.78rem;font-weight:500}
.b-green{background:#e8f6ec;color:#1c7a32}
.b-gold{background:#fff4d6;color:#9a6700}
.b-red{background:#fdecea;color:#b8311c}
.b-gray{background:#eef1f6;color:#5b6680}

/* page header */
.page-hero{background:linear-gradient(120deg,#1c7c3c,#2e9e4f);color:#fff;padding:28px 0;text-align:center}
.page-hero h1{font-size:2rem}
.page-hero p{color:#e6f5ec}
.breadcrumb{font-size:.85rem;color:#9aa3b8;margin-bottom:8px}
.breadcrumb a{color:var(--cyan)}

/* article */
.article{max-width:840px;margin:0 auto;background:#fff;border-radius:16px;box-shadow:var(--shadow);overflow:hidden}
.article .hero-img{height:320px;background:linear-gradient(135deg,#2e9e4f,#1c7c3c);display:flex;align-items:center;justify-content:center;color:#fff;font-size:4rem}
.article .hero-img img{width:100%;height:100%;object-fit:cover}
.article .content{padding:32px}
.article .content h1{color:var(--navy2);font-size:1.7rem;margin-bottom:10px}
.article .content .body{margin-top:18px;white-space:pre-line;color:#33405c}

/* ---------- Footer ---------- */
.site-footer{background:var(--navy);color:#cfe6d6;margin-top:32px}
.footer-grid{display:grid;grid-template-columns:1.5fr 1fr 1fr;gap:26px;padding:28px 40px 20px}
.footer-grid h4{color:#fff;margin-bottom:12px;font-size:1.05rem}
.footer-grid p{font-size:.9rem;margin-bottom:6px}
.footer-grid .concept{color:var(--green1);font-style:italic;margin-top:8px}
.footer-bottom{border-top:1px solid rgba(255,255,255,.12);text-align:center;padding:16px;font-size:.85rem;color:#9cc6a8}

/* success */
.success-box{max-width:560px;margin:0 auto;background:#fff;border-radius:18px;box-shadow:var(--shadow);padding:32px 36px;text-align:center}
.success-box .check{width:84px;height:84px;border-radius:50%;background:var(--green-grad);display:flex;align-items:center;justify-content:center;font-size:2.6rem;color:#fff;margin:0 auto 18px}
.code-box{background:#f4f7fc;border:2px dashed var(--green2);border-radius:12px;padding:16px;margin:20px 0;font-size:1.4rem;font-weight:700;color:var(--navy2);letter-spacing:2px}

/* speakers */
.speaker-grid{display:grid;grid-template-columns:repeat(3,1fr);gap:22px}
.speaker-card{background:#fff;border-radius:16px;overflow:hidden;box-shadow:var(--shadow);transition:.2s;display:flex;flex-direction:column}
.speaker-card:hover{transform:translateY(-5px)}
.speaker-card .sp-photo{height:240px;background:linear-gradient(135deg,#2e9e4f,#1c7c3c);display:flex;align-items:center;justify-content:center}
.speaker-card .sp-photo img{width:100%;height:100%;object-fit:cover}
.speaker-card .sp-photo span{font-size:4rem}
.speaker-card .sp-body{padding:18px}
.speaker-card h3{color:var(--navy2);font-size:1.15rem;margin-bottom:4px}
.speaker-card .sp-pos{color:var(--green2);font-size:.9rem;font-weight:500;margin-bottom:2px}
.speaker-card .sp-org{color:var(--muted);font-size:.86rem;margin-bottom:8px}
.speaker-card .sp-topic{background:#eaf6ee;color:var(--green2);font-size:.82rem;padding:6px 12px;border-radius:8px;margin-bottom:8px}
.speaker-card .sp-bio{color:#55606e;font-size:.86rem;line-height:1.55}

/* documents */
.doc-list{display:flex;flex-direction:column;gap:12px;margin-bottom:26px}
.doc-item{display:flex;align-items:center;gap:16px;background:#fff;border:1px solid var(--line);border-radius:12px;padding:16px 20px;box-shadow:var(--shadow);transition:.15s;color:inherit}
.doc-item:hover{border-color:var(--green2);transform:translateX(4px)}
.doc-item .doc-ic{font-size:2rem;flex-shrink:0}
.doc-item .doc-info{flex:1;min-width:0}
.doc-item .doc-title{font-weight:600;color:var(--navy2)}
.doc-item .doc-desc{color:var(--muted);font-size:.9rem;margin-top:2px}
.doc-item .doc-meta{color:#9aa3b8;font-size:.8rem;margin-top:4px}
.doc-item .doc-dl{flex-shrink:0;background:var(--green-grad);color:#06351a;font-weight:600;padding:8px 18px;border-radius:24px;font-size:.9rem}

/* highlight zones (about) */
.zone-grid{display:grid;grid-template-columns:repeat(3,1fr);gap:16px}
.zone-card{background:rgba(255,255,255,.95);border-radius:14px;padding:22px 20px;position:relative;box-shadow:var(--shadow)}
.zone-card .zn{display:grid;place-items:center;width:38px;height:38px;border-radius:50%;background:var(--green-grad);color:#06351a;font-weight:700;margin-bottom:10px}
.zone-card h3{color:var(--navy2);font-size:1.05rem;margin-bottom:6px}
.zone-card p{color:var(--muted);font-size:.9rem;line-height:1.5}

/* academic themes (about) */
.theme-list{display:flex;flex-direction:column;gap:12px}
.theme-item{display:flex;gap:16px;align-items:flex-start;background:#fff;border:1px solid var(--line);border-left:4px solid var(--green2);border-radius:12px;padding:16px 20px;box-shadow:var(--shadow)}
.theme-item .th-ic{font-size:1.8rem;flex-shrink:0}
.theme-item h3{color:var(--navy2);font-size:1.05rem;margin-bottom:2px}
.theme-item p{color:var(--muted);font-size:.9rem}

/* ---------- Responsive ---------- */
@media(max-width:960px){
  .features{grid-template-columns:repeat(2,1fr)}
  .news-grid{grid-template-columns:repeat(2,1fr)}
  .stat-cards{grid-template-columns:repeat(2,1fr)}
  .chart-grid{grid-template-columns:1fr}
  .speaker-grid{grid-template-columns:repeat(2,1fr)}
  .reg-cards-3{grid-template-columns:repeat(2,1fr)}
  .zone-grid{grid-template-columns:repeat(2,1fr)}
  .features.feat6{grid-template-columns:repeat(2,1fr)}
  .hero-overlay .btn{padding:12px 24px;font-size:1.08rem}
}
@media(max-width:560px){
  .hero-overlay{bottom:6%;gap:8px}
  .hero-overlay .btn{padding:8.4px 15.6px;font-size:.94rem;border-radius:20px}
}
@media(max-width:680px){
  .hero-overlay{bottom:calc(6% + 0.2in)}
  .navtoggle-label{display:block;color:var(--navy2);font-size:1.6rem;cursor:pointer}
  .menu{display:none;position:absolute;top:100%;left:0;right:0;flex-direction:column;background:#fff;border-top:1px solid var(--line);box-shadow:var(--shadow);padding:10px}
  .navtoggle:checked ~ .menu{display:flex}
  .menu a{width:100%}
  .navbar-inner{position:relative}
  .hero h1{font-size:2rem}.hero .th{font-size:1.2rem}
  .features,.features.feat6,.news-grid,.reg-cards,.reg-cards-3,.stat-cards,.form-row,.footer-grid,.speaker-grid,.zone-grid{grid-template-columns:1fr}
  .doc-item{flex-wrap:wrap}
  .container{padding:0 16px}
}

/* ============ ชุดสี (Theme palettes) ============ */
html[data-theme="blue"]{
  --navy:#0a2a5c; --navy2:#15539e; --navy3:#2f80e0;
  --green1:#4a92e3; --green2:#2f80e0; --green-grad:linear-gradient(90deg,#2f80e0,#15539e);
  --bg:#eef3fb; --shadow:0 8px 30px rgba(10,42,92,.12);
}
html[data-theme="purple"]{
  --navy:#3a1d63; --navy2:#5e3aa0; --navy3:#7d5ba6;
  --green1:#9168c8; --green2:#6b4a9e; --green-grad:linear-gradient(90deg,#7d5ba6,#523a87);
  --bg:#f5f2fb; --shadow:0 8px 30px rgba(58,29,99,.12);
}
html[data-theme="teal"]{
  --navy:#0a3d40; --navy2:#0f6b66; --navy3:#13a89e;
  --green1:#2bc0b4; --green2:#13a89e; --green-grad:linear-gradient(90deg,#16b5a8,#0f7a72);
  --bg:#eef8f7; --shadow:0 8px 30px rgba(10,61,64,.12);
}
html[data-theme="orange"]{
  --navy:#5c2410; --navy2:#b24a1f; --navy3:#e8631e;
  --green1:#f0894a; --green2:#e8631e; --green-grad:linear-gradient(90deg,#ef7d1a,#c44f12);
  --bg:#fdf3ee; --shadow:0 8px 30px rgba(92,36,16,.12);
}

/* ============ ปุ่มเลือกชุดสี (Theme switcher) ============ */
.theme-fab{position:fixed;right:18px;bottom:18px;z-index:70}
.theme-fab .fab-btn{width:52px;height:52px;border-radius:50%;background:var(--green-grad);color:#fff;
  border:none;font-size:1.4rem;box-shadow:0 6px 20px rgba(0,0,0,.28);cursor:pointer;display:grid;place-items:center;transition:.2s}
.theme-fab .fab-btn:hover{transform:scale(1.06)}
.theme-panel{position:absolute;bottom:62px;right:0;background:#fff;border:1px solid var(--line);
  border-radius:14px;box-shadow:0 12px 34px rgba(0,0,0,.2);padding:14px 16px;width:210px;display:none}
.theme-panel.open{display:block;animation:bfade .2s ease}
.theme-panel h4{font-size:.92rem;color:var(--ink);margin:0 0 10px;font-weight:600}
.theme-swatches{display:flex;gap:10px;flex-wrap:wrap}
.theme-swatch{width:34px;height:34px;border-radius:50%;cursor:pointer;border:3px solid #fff;box-shadow:0 0 0 1px var(--line);transition:.15s}
.theme-swatch:hover{transform:scale(1.12)}
.theme-swatch.active{box-shadow:0 0 0 2px var(--ink)}