/* =====================================================================
   MOOC Platform — Tailwind-inspired flat UI
   Font: Sarabun. No gradients. CSS variables set per active theme.
   Design language mirrors Tailwind: slate palette, rounded-lg,
   shadow-sm, ring focus states, consistent spacing scale.
   ===================================================================== */
:root{
  --primary:#2563eb;
  --secondary:#1e40af;
  --accent:#f59e0b;

  /* slate-based neutral palette (Tailwind) */
  --bg:#f8fafc;            /* slate-50 */
  --surface:#ffffff;
  --surface-2:#f1f5f9;     /* slate-100 */
  --surface-3:#e2e8f0;     /* slate-200 */
  --text:#0f172a;          /* slate-900 */
  --text-muted:#64748b;    /* slate-500 */
  --border:#e2e8f0;        /* slate-200 */
  --border-strong:#cbd5e1; /* slate-300 */
  --ring:color-mix(in srgb, var(--primary) 35%, transparent);
  --shadow-sm:0 1px 2px 0 rgba(15,23,42,.06);
  --shadow:0 1px 3px 0 rgba(15,23,42,.1),0 1px 2px -1px rgba(15,23,42,.07);
  --shadow-md:0 4px 6px -1px rgba(15,23,42,.1),0 2px 4px -2px rgba(15,23,42,.07);
  --shadow-lg:0 10px 15px -3px rgba(15,23,42,.1),0 4px 6px -4px rgba(15,23,42,.06);
  --radius:0.75rem;        /* rounded-xl */
  --radius-md:0.5rem;      /* rounded-lg */
  --radius-sm:0.375rem;    /* rounded-md */
}
[data-mode="dark"]{
  --bg:#0f172a;            /* slate-900 */
  --surface:#1e293b;       /* slate-800 */
  --surface-2:#334155;     /* slate-700 */
  --surface-3:#475569;     /* slate-600 */
  --text:#f1f5f9;          /* slate-100 */
  --text-muted:#94a3b8;    /* slate-400 */
  --border:#334155;        /* slate-700 */
  --border-strong:#475569; /* slate-600 */
  --shadow-sm:0 1px 2px 0 rgba(0,0,0,.4);
  --shadow:0 1px 3px 0 rgba(0,0,0,.5);
  --shadow-md:0 4px 6px -1px rgba(0,0,0,.5);
  --shadow-lg:0 10px 15px -3px rgba(0,0,0,.55);
}

*{box-sizing:border-box}
html,body{margin:0;padding:0}
body{
  font-family:'Sarabun',system-ui,'Segoe UI',sans-serif;
  background:var(--bg);
  color:var(--text);
  font-size:15px;
  line-height:1.6;
  -webkit-font-smoothing:antialiased;
  text-rendering:optimizeLegibility;
}
a{color:var(--primary);text-decoration:none;transition:color .12s,opacity .12s}
a:hover{text-decoration:none;opacity:.82}
.btn:hover,.nav a:hover,.course-card:hover,.stat:hover,.chip:hover,a.brand:hover{opacity:1}
.brand{display:flex;align-items:center;gap:10px}
.brand img{height:34px;width:auto;object-fit:contain;border-radius:6px}
h1,h2,h3,h4{margin:.2em 0 .5em;font-weight:700;line-height:1.3;letter-spacing:-.01em}
img{max-width:100%}

/* ---------- Layout shell ---------- */
.app{display:flex;min-height:100vh}
.sidebar{
  width:264px;flex-shrink:0;background:var(--surface);
  border-right:1px solid var(--border);padding:18px 14px;
  position:sticky;top:0;height:100vh;overflow-y:auto;
}
.sidebar .brand{display:flex;align-items:center;gap:10px;font-weight:800;
  font-size:1.15rem;margin-bottom:18px;color:var(--text);padding:6px 8px}
.sidebar .brand .logo{font-size:1.7rem}
.nav-group-title{font-size:.72rem;color:var(--text-muted);text-transform:uppercase;
  letter-spacing:.06em;margin:18px 10px 6px;font-weight:600}
.nav a{display:flex;align-items:center;gap:11px;padding:9px 12px;border-radius:var(--radius-md);
  color:var(--text);font-weight:500;margin-bottom:2px;transition:background .12s,color .12s}
.nav a:hover{background:var(--surface-2);text-decoration:none}
.nav a.active{background:var(--primary);color:#fff;box-shadow:var(--shadow-sm)}
.nav a .ic{font-size:1.15rem;width:1.5rem;text-align:center}

.main{flex:1;min-width:0;display:flex;flex-direction:column}
.topbar{display:flex;align-items:center;gap:14px;padding:13px 24px;
  background:color-mix(in srgb,var(--surface) 85%,transparent);backdrop-filter:blur(8px);
  border-bottom:1px solid var(--border);position:sticky;top:0;z-index:30}
.topbar .spacer{flex:1}
.content{padding:26px;max-width:1200px;width:100%;margin:0 auto}

/* ---------- Buttons ---------- */
.btn{display:inline-flex;align-items:center;justify-content:center;gap:8px;padding:0 16px;
  height:40px;min-width:40px;border-radius:var(--radius-md);vertical-align:middle;
  border:1px solid transparent;background:var(--primary);color:#fff;font-weight:600;
  font-family:inherit;font-size:.9rem;cursor:pointer;box-shadow:var(--shadow-sm);
  transition:filter .15s,box-shadow .15s,transform .05s;line-height:1;white-space:nowrap}
.btn:hover{filter:brightness(1.06);text-decoration:none}
.btn:active{transform:translateY(1px)}
.btn:focus-visible{outline:none;box-shadow:0 0 0 3px var(--ring)}
.btn .ic{font-size:1.05rem}
.btn-secondary{background:var(--surface);color:var(--text);border-color:var(--border-strong)}
.btn-secondary:hover{background:var(--surface-2);filter:none}
.btn-accent{background:var(--accent);color:#1f2937}
.btn-danger{background:#dc2626}
.btn-success{background:#16a34a}
.btn-sm{height:34px;min-width:34px;padding:0 11px;font-size:.82rem;border-radius:var(--radius-sm)}
.btn-block{width:100%}
/* keep form-wrapped buttons aligned with their siblings in action rows */
.row-actions form,.inline form,.page-head form{display:inline-flex;margin:0}
.row-actions{align-items:center}
.btn:disabled{opacity:.55;cursor:not-allowed}

/* ---------- Cards / tables ---------- */
.card{background:var(--surface);border:1px solid var(--border);border-radius:var(--radius);
  box-shadow:var(--shadow-sm);padding:22px;margin-bottom:18px}
.card-title{display:flex;align-items:center;gap:10px;font-size:1.1rem;font-weight:700;margin-bottom:16px}
.grid{display:grid;gap:16px}
.grid-2{grid-template-columns:repeat(2,1fr)}
.grid-3{grid-template-columns:repeat(3,1fr)}
.grid-4{grid-template-columns:repeat(4,1fr)}
@media(max-width:900px){.grid-2,.grid-3,.grid-4{grid-template-columns:1fr}}
/* narrow icon column + partner field fills the rest (avoids empty gap) */
.grid.grid-icon{grid-template-columns:max-content 1fr;align-items:start}
@media(max-width:560px){.grid.grid-icon{grid-template-columns:1fr}}

.stat{background:var(--surface);border:1px solid var(--border);border-radius:var(--radius);
  padding:18px;display:flex;align-items:center;gap:14px;box-shadow:var(--shadow-sm);
  transition:box-shadow .15s,transform .12s}
.stat:hover{box-shadow:var(--shadow-md);transform:translateY(-2px)}
.stat .ic{font-size:2rem;width:54px;height:54px;display:grid;place-items:center;
  background:var(--surface-2);border-radius:var(--radius-md)}
.stat .num{font-size:1.6rem;font-weight:800;line-height:1;letter-spacing:-.02em}
.stat .lbl{color:var(--text-muted);font-size:.88rem}

table{width:100%;border-collapse:collapse;font-size:.9rem}
th,td{text-align:left;padding:12px 14px;border-bottom:1px solid var(--border);vertical-align:middle}
th{color:var(--text-muted);font-weight:600;font-size:.74rem;text-transform:uppercase;letter-spacing:.05em;
  background:var(--surface-2)}
thead th:first-child{border-top-left-radius:var(--radius-sm)}
thead th:last-child{border-top-right-radius:var(--radius-sm)}
tbody tr{transition:background .1s}
tbody tr:hover{background:var(--surface-2)}
.table-wrap{overflow-x:auto;border:1px solid var(--border);border-radius:var(--radius-md)}
.table-wrap table{font-size:.9rem}
.table-wrap tbody tr:last-child td{border-bottom:none}

/* ---------- Forms (Tailwind @forms style) ---------- */
.form-row{margin-bottom:18px}
label{display:block;font-weight:600;margin-bottom:7px;font-size:.86rem;color:var(--text)}
label .ic{margin-right:4px}
input:not([type]),
input[type=text],input[type=email],input[type=password],input[type=number],
input[type=url],input[type=date],input[type=tel],input[type=search],input[type=time],
input[type=datetime-local],select,textarea{
  width:100%;padding:9px 12px;border:1px solid var(--border-strong);border-radius:var(--radius-md);
  background:var(--surface);color:var(--text);font-family:inherit;font-size:.9rem;line-height:1.5;
  box-shadow:var(--shadow-sm);transition:border-color .12s,box-shadow .12s;appearance:none}
input::placeholder,textarea::placeholder{color:var(--text-muted);opacity:.8}
textarea{min-height:110px;resize:vertical}
input:not([type]):focus,
input[type=text]:focus,input[type=email]:focus,input[type=password]:focus,input[type=number]:focus,
input[type=url]:focus,input[type=date]:focus,input[type=tel]:focus,input[type=search]:focus,
select:focus,textarea:focus{
  outline:none;border-color:var(--primary);box-shadow:0 0 0 3px var(--ring)}
input:disabled,select:disabled,textarea:disabled{background:var(--surface-2);color:var(--text-muted);cursor:not-allowed}
/* native select arrow */
select{background-image:url("data:image/svg+xml;charset=utf-8,%3Csvg xmlns='http://www.w3.org/2000/svg' fill='none' viewBox='0 0 20 20'%3E%3Cpath stroke='%2364748b' stroke-linecap='round' stroke-linejoin='round' stroke-width='1.7' d='m6 8 4 4 4-4'/%3E%3C/svg%3E");
  background-position:right .65rem center;background-repeat:no-repeat;background-size:1.1em;padding-right:2.2rem}
input[type=color]{padding:4px;height:42px;cursor:pointer}
/* file input — Tailwind file: pseudo style */
input[type=file]{width:100%;font-size:.86rem;color:var(--text-muted);
  border:1px dashed var(--border-strong);border-radius:var(--radius-md);padding:8px;background:var(--surface);cursor:pointer}
input[type=file]::file-selector-button{margin-right:12px;border:none;background:var(--surface-2);
  color:var(--text);padding:7px 14px;border-radius:var(--radius-sm);font-family:inherit;font-weight:600;
  font-size:.84rem;cursor:pointer;transition:background .12s}
input[type=file]::file-selector-button:hover{background:var(--surface-3)}
/* checkboxes & radios */
input[type=checkbox],input[type=radio]{width:1.05rem;height:1.05rem;accent-color:var(--primary);cursor:pointer;
  vertical-align:middle}
.hint{color:var(--text-muted);font-size:.8rem;margin-top:5px;line-height:1.5}
.inline{display:flex;gap:12px;align-items:center;flex-wrap:wrap}
.check{display:flex;align-items:center;gap:8px;font-weight:500;cursor:pointer;margin-bottom:0}
.check input{width:auto}
fieldset{border:1px solid var(--border);border-radius:var(--radius-md);padding:14px}
code{background:var(--surface-2);padding:2px 7px;border-radius:var(--radius-sm);font-size:.85em;
  font-family:ui-monospace,'Cascadia Code',monospace}

/* ---------- Badges ---------- */
.badge{display:inline-flex;align-items:center;gap:5px;padding:3px 10px;border-radius:999px;
  font-size:.76rem;font-weight:600;line-height:1.4;white-space:nowrap}
.badge-gray{background:var(--surface-2);color:var(--text-muted)}
.badge-green{background:#dcfce7;color:#15803d}
.badge-red{background:#fee2e2;color:#b91c1c}
.badge-blue{background:#dbeafe;color:#1d4ed8}
.badge-amber{background:#fef3c7;color:#b45309}
[data-mode="dark"] .badge-green{background:#052e1b;color:#4ade80}
[data-mode="dark"] .badge-red{background:#3a0f0f;color:#f87171}
[data-mode="dark"] .badge-blue{background:#0c1e3e;color:#60a5fa}
[data-mode="dark"] .badge-amber{background:#341c08;color:#fbbf24}

/* ---------- Course cards ---------- */
.course-card{background:var(--surface);border:1px solid var(--border);border-radius:var(--radius);
  overflow:hidden;box-shadow:var(--shadow-sm);display:flex;flex-direction:column;
  transition:transform .15s,box-shadow .15s}
.course-card:hover{transform:translateY(-4px);box-shadow:var(--shadow-lg)}
.course-thumb{height:148px;background:var(--surface-2);display:grid;place-items:center;font-size:3.5rem}
.course-card .body{padding:16px;flex:1;display:flex;flex-direction:column;gap:8px}
.course-card .cat{font-size:.8rem;color:var(--text-muted);display:flex;align-items:center;gap:5px}
.course-card h3{font-size:1.02rem;margin:0;letter-spacing:-.01em}

/* course detail hero (responsive) */
.course-hero{display:flex;gap:18px;align-items:center;flex-wrap:wrap}
.course-hero .thumb{width:210px;height:135px;object-fit:cover;border-radius:var(--radius-md);
  border:1px solid var(--border);flex-shrink:0}
.course-hero .thumb-icon{font-size:4rem;width:135px;text-align:center;flex-shrink:0}
.course-hero .info{flex:1;min-width:230px}
.course-hero .info h1{margin:.15em 0}
.course-hero .actions{flex-shrink:0}
@media(max-width:600px){
  .course-hero{flex-direction:column;align-items:stretch;text-align:center}
  .course-hero .thumb{width:100%;height:190px}
  .course-hero .thumb-icon{width:100%}
  .course-hero .info{min-width:0}
  .course-hero .info .inline{justify-content:center}
  .course-hero .actions,.course-hero .actions .btn,.course-hero .actions form{width:100%}
}

/* ---------- Flash / alerts ---------- */
.alert{padding:13px 16px;border-radius:var(--radius-md);margin-bottom:16px;display:flex;align-items:center;
  gap:10px;font-weight:500;font-size:.9rem;border:1px solid transparent}
.alert .ic{font-size:1.25rem}
.alert-success{background:#dcfce7;color:#15803d;border-color:#bbf7d0}
.alert-error{background:#fee2e2;color:#b91c1c;border-color:#fecaca}
.alert-info{background:#dbeafe;color:#1d4ed8;border-color:#bfdbfe}
[data-mode="dark"] .alert-success{background:#052e1b;color:#4ade80;border-color:#14532d}
[data-mode="dark"] .alert-error{background:#3a0f0f;color:#f87171;border-color:#7f1d1d}
[data-mode="dark"] .alert-info{background:#0c1e3e;color:#60a5fa;border-color:#1e3a8a}

/* ---------- Loading overlay ---------- */
#loading-overlay{position:fixed;inset:0;background:rgba(248,250,252,.7);backdrop-filter:blur(2px);
  display:none;align-items:center;justify-content:center;z-index:9999;flex-direction:column;gap:14px}
[data-mode="dark"] #loading-overlay{background:rgba(15,23,42,.7)}
#loading-overlay.show{display:flex}
.spinner{width:52px;height:52px;border:5px solid var(--surface-3);
  border-top-color:var(--primary);border-radius:50%;animation:spin .8s linear infinite}
@keyframes spin{to{transform:rotate(360deg)}}
.loading-text{font-weight:600;color:var(--text)}

/* ---------- Modal ---------- */
.modal-backdrop{position:fixed;inset:0;background:rgba(15,23,42,.55);backdrop-filter:blur(3px);
  display:none;align-items:flex-start;justify-content:center;z-index:1000;padding:48px 16px;overflow-y:auto}
.modal-backdrop.show{display:flex}
.modal{background:var(--surface);border-radius:var(--radius);max-width:640px;width:100%;
  box-shadow:var(--shadow-lg);border:1px solid var(--border);animation:pop .18s ease}
.modal.modal-lg{max-width:920px}
@keyframes pop{from{transform:translateY(-12px) scale(.98);opacity:0}to{transform:none;opacity:1}}
.modal-head{display:flex;align-items:center;gap:10px;padding:16px 22px;border-bottom:1px solid var(--border);
  font-weight:700;font-size:1.05rem}
.modal-head .close{margin-left:auto;cursor:pointer;font-size:1.4rem;color:var(--text-muted);
  background:none;border:none;line-height:1;width:32px;height:32px;border-radius:var(--radius-sm);
  display:grid;place-items:center;transition:background .12s}
.modal-head .close:hover{background:var(--surface-2)}
.modal-body{padding:22px}
.modal-foot{padding:14px 22px;border-top:1px solid var(--border);display:flex;gap:10px;justify-content:flex-end;
  background:var(--surface-2);border-radius:0 0 var(--radius) var(--radius)}

/* ---------- Misc ---------- */
.page-head{display:flex;align-items:center;gap:12px;margin-bottom:20px;flex-wrap:wrap}
.page-head h1{font-size:1.5rem;margin:0;display:flex;align-items:center;gap:10px;letter-spacing:-.02em}
.page-head .spacer{flex:1}
.empty{text-align:center;padding:54px 20px;color:var(--text-muted)}
.empty .ic{font-size:3rem;display:block;margin-bottom:10px;opacity:.7}
.avatar{width:38px;height:38px;border-radius:50%;background:var(--primary);color:#fff;
  display:grid;place-items:center;font-weight:700;font-size:.95rem;flex-shrink:0}
img.avatar{object-fit:cover}
.theme-swatch{width:46px;height:46px;border-radius:var(--radius-md);border:3px solid transparent;cursor:pointer;
  display:inline-block;box-shadow:var(--shadow-sm);transition:transform .12s}
.theme-swatch:hover{transform:scale(1.08)}
.theme-swatch.active{border-color:var(--text)}
.user-menu{display:flex;align-items:center;gap:10px;cursor:pointer;font-size:.9rem}
.row-actions{display:flex;gap:6px;flex-wrap:wrap;align-items:center}
.public-header{background:color-mix(in srgb,var(--surface) 85%,transparent);backdrop-filter:blur(8px);
  border-bottom:1px solid var(--border);padding:13px 24px;display:flex;align-items:center;gap:12px;
  position:sticky;top:0;z-index:30}
.public-header .brand{font-weight:800;font-size:1.15rem;display:flex;align-items:center;gap:8px}
.chips{display:flex;gap:8px;flex-wrap:wrap;margin-bottom:20px}
.chip{padding:7px 15px;border-radius:999px;background:var(--surface);border:1px solid var(--border-strong);
  font-weight:600;font-size:.86rem;cursor:pointer;display:inline-flex;gap:6px;align-items:center;
  box-shadow:var(--shadow-sm);transition:background .12s,color .12s,border-color .12s}
.chip:hover{background:var(--surface-2);text-decoration:none}
.chip.active{background:var(--primary);color:#fff;border-color:var(--primary)}

/* ---------- Icon picker ---------- */
input[name="icon"],input[name^="opt_icon"]{
  width:5rem;max-width:100%;text-align:center;font-size:1.4rem;line-height:1;cursor:pointer;caret-color:transparent;
  background-image:url("data:image/svg+xml;charset=utf-8,%3Csvg xmlns='http://www.w3.org/2000/svg' fill='none' viewBox='0 0 20 20'%3E%3Cpath stroke='%2364748b' stroke-linecap='round' stroke-linejoin='round' stroke-width='1.7' d='m6 8 4 4 4-4'/%3E%3C/svg%3E");
  background-position:right .4rem center;background-repeat:no-repeat;background-size:.95em;padding-right:1.6rem;padding-left:.6rem}
input[name^="opt_icon"]{width:4rem;font-size:1.2rem}
.iconpicker-pop{position:absolute;z-index:1100;width:320px;max-width:calc(100vw - 24px);
  background:var(--surface);border:1px solid var(--border);border-radius:var(--radius-md);
  box-shadow:var(--shadow-lg);padding:12px;display:none}
.iconpicker-pop.show{display:block}
.iconpicker-search{margin-bottom:10px}
.iconpicker-grid{display:grid;grid-template-columns:repeat(7,1fr);gap:4px;max-height:240px;overflow-y:auto}
.iconpicker-grid button{font-size:1.35rem;line-height:1;padding:7px 0;border:1px solid transparent;
  background:none;border-radius:var(--radius-sm);cursor:pointer;transition:background .1s}
.iconpicker-grid button:hover{background:var(--surface-2);border-color:var(--border)}
.iconpicker-empty{grid-column:1/-1;text-align:center;color:var(--text-muted);padding:20px;font-size:.85rem}
.iconpicker-cats{display:flex;gap:4px;flex-wrap:wrap;margin-bottom:8px}
.iconpicker-cats button{font-size:1.05rem;padding:4px 8px;border:1px solid var(--border);background:var(--surface);
  border-radius:999px;cursor:pointer}
.iconpicker-cats button.active{background:var(--primary);border-color:var(--primary)}

/* ---------- Hamburger / mobile sidebar ---------- */
.menu-toggle{display:none;background:var(--surface);border:1px solid var(--border-strong);
  border-radius:var(--radius-sm);width:40px;height:40px;font-size:1.2rem;cursor:pointer;
  align-items:center;justify-content:center;color:var(--text)}
.sidebar-backdrop{position:fixed;inset:0;background:rgba(15,23,42,.5);z-index:55;display:none}
.sidebar-backdrop.show{display:block}

/* ---------- Responsive ---------- */
@media(max-width:768px){
  body{font-size:14.5px}
  .menu-toggle{display:inline-flex}
  .sidebar{position:fixed;left:0;top:0;height:100dvh;z-index:60;width:80vw;max-width:300px;
    transform:translateX(-100%);transition:transform .25s ease;box-shadow:var(--shadow-lg)}
  .sidebar.open{transform:none}
  .content{padding:16px}
  .topbar{padding:11px 14px;gap:10px}
  .topbar strong{font-size:.95rem;overflow:hidden;text-overflow:ellipsis;white-space:nowrap}
  .user-menu span{display:none}            /* keep avatar, hide long name */
  .page-head h1{font-size:1.25rem}
  .public-header{padding:11px 14px;flex-wrap:wrap;gap:8px}
  .public-header .brand{font-size:1.05rem}
  .public-header .btn{padding:7px 11px;font-size:.82rem}
  .modal-backdrop{padding:16px 10px}
  .modal-foot{flex-direction:column-reverse}
  .modal-foot .btn{width:100%;justify-content:center}
  .card{padding:16px}
  .stat .num{font-size:1.4rem}
  .iconpicker-pop{width:calc(100vw - 24px)}
  .iconpicker-grid{grid-template-columns:repeat(6,1fr)}
}
@media(max-width:420px){
  .public-header .btn .ic{margin:0}
  .row-actions .btn-sm{padding:6px 9px}
}