/* ============================================================
   KP Science — คอร์สออนไลน์: สไตล์กลาง (หน้าเรียน + ห้องครู)
   สไตล์เรียบแบบเว็บ Apple: พื้นเทาอ่อน/ขาว · ตัวหนังสือดำ · ปุ่มแคปซูลสีฟ้า · การ์ดมุมโค้งไม่มีขอบ · แถบเมนูโปร่งแสง
   ฟอนต์ระบบ (บน iPhone/Mac = ฟอนต์ของ Apple) · เครื่องอื่นใช้ IBM Plex Sans Thai
   สีประจำบทบาทอยู่ใน [data-role] บน <body>
   ============================================================ */
:root{
  --bg:#f5f5f7;--surface:#ffffff;--surface2:#f5f5f7;--surface3:#e8e8ed;
  --line:rgba(0,0,0,.08);--line2:rgba(0,0,0,.14);
  --text:#1d1d1f;--text2:#424245;--muted:#6e6e73;
  --accent:#0071e3;--accent-hover:#0077ed;--accent-soft:#e8f2fd;--accent-ink:#ffffff;--link:#0066cc;
  --orange:#bf4800;--hl:#ffe270;
  --ok:#1a7f43;--ok-soft:#e5f4ea;--warn:#a05a00;--warn-soft:#fdf2e3;--bad:#d70015;--bad-soft:#fde8ea;
  --admin:#bf4800;--teacher:#8944ab;--student:#0071e3;--guest:#6e6e73;
  --role:var(--guest);
  --head:-apple-system,BlinkMacSystemFont,'SF Pro Display','Helvetica Neue','Sukhumvit Set','IBM Plex Sans Thai',sans-serif;
  --body:-apple-system,BlinkMacSystemFont,'SF Pro Text','Helvetica Neue','Sukhumvit Set','IBM Plex Sans Thai Looped','IBM Plex Sans Thai',sans-serif;
  --mono:ui-monospace,'SF Mono',Menlo,'Share Tech Mono',monospace;
  --hand:var(--head);
  --r:18px;--ease:cubic-bezier(.25,.1,.25,1);
  --shadow-s:0 1px 3px rgba(0,0,0,.04);
  --shadow:0 4px 24px rgba(0,0,0,.08);
}
body[data-role=admin]{--role:var(--admin)}
body[data-role=teacher]{--role:var(--teacher)}
body[data-role=student]{--role:var(--student)}
*{box-sizing:border-box;margin:0;padding:0}
html{scroll-behavior:smooth;overflow-x:clip}
body{background:var(--bg);color:var(--text);font:17px/1.65 var(--body);-webkit-font-smoothing:antialiased}
a{color:inherit}
button,input,textarea,select{font:inherit;color:inherit;letter-spacing:inherit}
:focus-visible{outline:2px solid var(--accent);outline-offset:2px;border-radius:6px}
.hide,[hidden]{display:none!important}
.mono{font-family:var(--mono)}
/* หัวข้อเล็กเหนือหัวเรื่อง (eyebrow) */
.hand{font:600 15px/1.4 var(--head);color:var(--orange);letter-spacing:0}
.mark{color:inherit;background:none}

/* ---------- ปุ่ม: แคปซูล ---------- */
.btn{display:inline-flex;align-items:center;justify-content:center;gap:6px;font:400 15px/1.2 var(--body);padding:9px 18px;border-radius:980px;border:0;background:var(--surface3);text-decoration:none;cursor:pointer;transition:background .2s,color .2s,opacity .2s;white-space:nowrap;color:var(--text)}
.btn:hover{background:#dcdce1}
.btn.solid{background:var(--accent);color:#fff}
.btn.solid:hover{background:var(--accent-hover)}
.btn.ghost{background:transparent;color:var(--link)}
.btn.ghost:hover{background:transparent;text-decoration:underline}
.btn.ok{background:var(--ok);color:#fff}
.btn.ok:hover{filter:brightness(1.08)}
.btn.bad{background:var(--bad-soft);color:var(--bad)}
.btn.bad:hover{background:#fbd8dc}
.btn.sm{padding:7px 15px;font-size:14px}
.btn.xs{padding:4px 11px;font-size:13px}
.btn.lg{padding:12px 24px;font-size:17px}
.btn[disabled]{opacity:.4;cursor:default;pointer-events:none}
.link{color:var(--link);text-decoration:none}
.link:hover{text-decoration:underline}

/* ---------- ป้าย ---------- */
.pill{display:inline-flex;align-items:center;gap:5px;font:500 12px/1.5 var(--body);padding:2px 9px;border-radius:980px;background:var(--surface2);color:var(--text2);white-space:nowrap;letter-spacing:0}
.pill.ok{background:var(--ok-soft);color:var(--ok)}
.pill.warn{background:var(--warn-soft);color:var(--warn)}
.pill.bad{background:var(--bad-soft);color:var(--bad)}
.pill.info{background:var(--accent-soft);color:var(--accent)}
.pill.role{background:color-mix(in srgb,var(--role) 10%,#fff);color:var(--role)}
.count{display:inline-grid;place-items:center;min-width:20px;height:20px;padding:0 6px;border-radius:99px;background:var(--bad);color:#fff;font:600 11.5px var(--body)}

/* ---------- แถบบน: โปร่งแสง ---------- */
.topbar{position:sticky;top:0;z-index:200;height:52px;display:flex;align-items:center;gap:22px;padding:0 max(22px,calc((100% - 1024px)/2));background:rgba(255,255,255,.72);backdrop-filter:saturate(180%) blur(20px);-webkit-backdrop-filter:saturate(180%) blur(20px);border-bottom:1px solid var(--line)}
.logo{display:flex;align-items:center;gap:8px;text-decoration:none;flex-shrink:0}
.logo-mark{width:26px;height:26px;border-radius:7px;background:var(--text);display:grid;place-items:center;font:700 11px var(--head);color:#fff;letter-spacing:0}
.logo-text{font:600 17px var(--head)}.logo-text b{font-weight:600}
.logo-sub{font:400 13px var(--body);color:var(--muted);padding-left:2px}
.nav{display:flex;gap:4px}
.nav a{padding:6px 10px;font:400 14px var(--body);color:var(--text2);text-decoration:none;transition:color .2s;border-radius:8px}
.nav a:hover{color:var(--text)}
.nav a.on{color:var(--text);font-weight:600}
.tb-sp{flex:1}
.tb-auth{display:flex;gap:6px;align-items:center}

/* ปุ่มผู้ใช้ + เมนู */
.who{position:relative}
.who-btn{display:flex;align-items:center;gap:9px;padding:3px 12px 3px 3px;border-radius:99px;border:0;background:transparent;cursor:pointer;transition:background .2s}
.who-btn:hover,.who.open .who-btn{background:rgba(0,0,0,.05)}
.avatar{width:30px;height:30px;border-radius:50%;display:grid;place-items:center;font:600 13px var(--head);color:#fff;background:var(--role);flex:none}
.who-txt{display:flex;flex-direction:column;line-height:1.2;text-align:left;max-width:150px}
.who-txt b{font:500 13.5px var(--body);overflow:hidden;text-overflow:ellipsis;white-space:nowrap}
.who-txt small{font:400 11.5px var(--body);color:var(--muted)}
.menu{position:absolute;right:0;top:calc(100% + 8px);min-width:240px;background:rgba(255,255,255,.92);backdrop-filter:blur(20px);-webkit-backdrop-filter:blur(20px);border:1px solid var(--line);border-radius:14px;box-shadow:0 10px 40px rgba(0,0,0,.14);padding:6px;display:none;z-index:300}
.who.open .menu{display:block}
.menu .mh{padding:10px 12px 10px;border-bottom:1px solid var(--line);margin-bottom:4px}
.menu .mh b{display:block;font:600 15px var(--head)}
.menu .mh small{color:var(--muted);font-size:13px;word-break:break-all}
.menu a,.menu button{display:flex;align-items:center;gap:10px;width:100%;padding:8px 12px;border-radius:8px;border:0;background:none;text-decoration:none;font:400 15px var(--body);cursor:pointer;text-align:left;color:var(--text)}
.menu a:hover,.menu button:hover{background:rgba(0,0,0,.05)}
.menu .danger{color:var(--bad)}

/* ---------- การ์ด / แผง ---------- */
.card{border:0;border-radius:var(--r);background:var(--surface);padding:24px}
.card-h{display:flex;align-items:center;gap:10px;flex-wrap:wrap;margin-bottom:14px}
.card-h h2,.card-h h3{font:600 19px/1.35 var(--head)}
.card-h .sp{flex:1}
.sub{color:var(--muted);font-size:15px}
.empty{color:var(--muted);padding:40px 20px;text-align:center;border-radius:var(--r);background:var(--surface)}
.empty .ic{font-size:30px;display:block;margin-bottom:6px}
.note{font-size:14.5px;color:var(--text2);background:var(--surface2);border-radius:12px;padding:12px 16px;line-height:1.6}
.bar{height:6px;border-radius:9px;background:var(--surface3);overflow:hidden}
.bar i{display:block;height:100%;border-radius:9px;background:var(--accent);transition:width .6s var(--ease)}
.skel{height:18px;border-radius:8px;background:linear-gradient(90deg,#ececf0,#e2e2e7,#ececf0);background-size:200% 100%;animation:sk 1.2s linear infinite;margin:12px 0}
@keyframes sk{to{background-position:-200% 0}}

/* ---------- ฟอร์ม ---------- */
.field{display:flex;flex-direction:column;gap:6px}
.field>label{font:500 14px var(--body);color:var(--text2)}
.field .hint{font-size:13px;color:var(--muted)}
.input,.field input:not([type=checkbox]),.field textarea,.field select{width:100%;background:var(--surface);border:1px solid #d2d2d7;border-radius:12px;padding:11px 14px;outline:none;transition:border-color .2s,box-shadow .2s;font-size:16px}
.input:focus,.field input:focus,.field textarea:focus,.field select:focus{border-color:var(--accent);box-shadow:0 0 0 4px rgba(0,113,227,.15)}
.err{color:var(--bad);font-size:14px;min-height:1.3em}

/* ---------- toast ---------- */
.toast{position:fixed;left:50%;bottom:28px;transform:translate(-50%,90px);background:rgba(29,29,31,.92);backdrop-filter:blur(10px);color:#fff;padding:11px 20px;border-radius:980px;transition:.35s var(--ease);z-index:9000;opacity:0;font:500 15px var(--body);max-width:calc(100vw - 32px);box-shadow:0 8px 30px rgba(0,0,0,.2)}
.toast.show{transform:translate(-50%,0);opacity:1}
.toast.bad{background:var(--bad)}

@media (max-width:640px){
  body{font-size:16px}
  .topbar{height:48px;gap:12px;padding:0 16px}
  .who-txt{display:none}
  .who-btn{padding:3px}
  .logo-sub{display:none}
  .btn.lg{padding:11px 20px;font-size:16px}
}
@media (prefers-reduced-motion:reduce){*{animation:none!important;transition:none!important;scroll-behavior:auto!important}}

/* ---------- การเคลื่อนไหว (แบบเว็บ Apple) ----------
   .reveal ใส่โดย KPC.motion() → ลอยขึ้น + จางเข้าเมื่อเลื่อนมาเห็น (--d = หน่วงไล่ลำดับ)
   ผู้ใช้ที่ตั้ง “ลดการเคลื่อนไหว” ไว้ จะไม่เห็นการเคลื่อนไหวเลย */
:root{--ease-out:cubic-bezier(.16,1,.3,1)}
.reveal{opacity:0;transform:translateY(30px);transition:opacity .9s var(--ease-out),transform .9s var(--ease-out)!important;transition-delay:var(--d,0s)!important}
.reveal.in{opacity:1;transform:none}
.page-in{animation:pagein .45s var(--ease-out) both}
@keyframes pagein{from{opacity:0;transform:translateY(8px)}to{opacity:1;transform:none}}
.btn:active,.donebtn:active,.quiz-opts button:active{transform:scale(.97)}
.topbar{transition:background .3s,box-shadow .3s}
.topbar.scrolled{background:rgba(255,255,255,.85);box-shadow:0 1px 0 var(--line)}
@media (prefers-reduced-motion:reduce){.reveal{opacity:1!important;transform:none!important}.page-in{animation:none}}

/* ---------- ธีมมืดแบบเว็บ satriwit-science (body.theme-dark) — ใช้กับห้องครู ----------
   เปลี่ยนสีหลักผ่านตัวแปร แล้วเก็บจุดที่ใส่สีตายตัว */
body.theme-dark{
  --bg:#000;--surface:#1d1d1f;--surface2:#2c2c2e;--surface3:#3a3a3c;
  --line:rgba(255,255,255,.09);--line2:rgba(255,255,255,.18);
  --text:#f5f5f7;--text2:#d2d2d7;--muted:#98989d;
  --accent-soft:rgba(10,132,255,.2);--link:#2997ff;--orange:#ff9f45;
  --ok:#30d158;--ok-soft:rgba(48,209,88,.16);--warn:#ffb340;--warn-soft:rgba(255,159,10,.16);--bad:#ff453a;--bad-soft:rgba(255,69,58,.16);
  --shadow:0 10px 40px rgba(0,0,0,.6);
  --ap-grad:linear-gradient(90deg,#ff5f6d,#ffb347 45%,#a66cff);
  color-scheme:dark;background:#000;color:var(--text)
}
body.theme-dark::before{content:"";position:fixed;top:-30vmax;left:-25vmax;width:70vmax;height:70vmax;border-radius:50%;background:radial-gradient(circle,rgba(255,95,109,.14),transparent 60%);filter:blur(60px);pointer-events:none;z-index:0}
body.theme-dark::after{content:"";position:fixed;bottom:-35vmax;right:-25vmax;width:70vmax;height:70vmax;border-radius:50%;background:radial-gradient(circle,rgba(166,108,255,.12),transparent 60%);filter:blur(60px);pointer-events:none;z-index:0}
body.theme-dark main,body.theme-dark .layout,body.theme-dark .gate{position:relative;z-index:1}
body.theme-dark .topbar{background:rgba(22,22,23,.72);border-bottom-color:transparent;box-shadow:none}
body.theme-dark .topbar.scrolled{background:rgba(22,22,23,.85)}
body.theme-dark .logo-mark{background:#f5f5f7;color:#000}
body.theme-dark .btn{background:var(--surface2)}
body.theme-dark .btn:hover{background:var(--surface3)}
body.theme-dark .btn.solid{background:#0071e3}
body.theme-dark .btn.solid:hover{background:#0077ed}
body.theme-dark .btn.ghost{background:transparent}
body.theme-dark .btn.ok{background:var(--ok);color:#000}
body.theme-dark .btn.bad{background:var(--bad-soft);color:var(--bad)}
body.theme-dark .btn.outline{color:var(--link);box-shadow:inset 0 0 0 1px var(--link)}
body.theme-dark .input,body.theme-dark .field input:not([type=checkbox]),body.theme-dark .field textarea,body.theme-dark .field select{background:var(--surface2);border-color:var(--surface3);color:var(--text)}
body.theme-dark .field input:focus,body.theme-dark .field textarea:focus,body.theme-dark .field select:focus{border-color:#0a84ff;box-shadow:0 0 0 4px rgba(10,132,255,.22)}
body.theme-dark .who-btn:hover,body.theme-dark .who.open .who-btn{background:rgba(255,255,255,.08)}
body.theme-dark .menu{background:rgba(44,44,46,.94)}
body.theme-dark .menu a:hover,body.theme-dark .menu button:hover{background:rgba(255,255,255,.08)}
body.theme-dark .pill.role{background:color-mix(in srgb,var(--role) 22%,transparent)}
body.theme-dark .bar i{background:var(--ap-grad)}
body.theme-dark .skel{background:linear-gradient(90deg,#1d1d1f,#2c2c2e,#1d1d1f);background-size:200% 100%}
body.theme-dark .toast{background:rgba(58,58,60,.95)}
body.theme-dark .grad{background:var(--ap-grad);-webkit-background-clip:text;background-clip:text;color:transparent}