:root{
  --blue:#1F4E79; --blue2:#2E5C8A; --accent:#C00000;
  --bg:#f5f7fa; --card:#fff; --line:#dbe2ea; --text:#1c2733; --muted:#667;
}
*{box-sizing:border-box}
body{margin:0;font-family:"Noto Sans JP",system-ui,sans-serif;background:var(--bg);color:var(--text);line-height:1.7}
.wrap{max-width:1000px;margin:0 auto;padding:0 18px}
a{color:var(--blue2);text-decoration:none}
a:hover{text-decoration:underline}

/* Header */
.site-header{background:var(--blue);color:#fff}
.site-header .wrap{display:flex;align-items:center;justify-content:space-between;flex-wrap:wrap;gap:8px;padding:12px 18px}
.brand{color:#fff;font-weight:700;font-size:1.15rem}
.brand:hover{text-decoration:none;opacity:.9}
.site-header nav{display:flex;align-items:center;gap:14px;flex-wrap:wrap}
.site-header nav a{color:#e8f0f8}
.site-header nav .who{color:#b9cde0;font-size:.9rem}

main.wrap{padding-top:24px;padding-bottom:60px}
h1{color:var(--blue);font-size:1.6rem}
h2{color:var(--blue);font-size:1.25rem;margin-top:1.6em}
h3{color:var(--blue2)}

/* Hero */
.hero{background:linear-gradient(135deg,#1F4E79,#2E5C8A);color:#fff;padding:34px 24px;border-radius:12px;margin-bottom:8px}
.hero h1{color:#fff;margin:0 0 6px}
.hero p{margin:0;color:#dbe8f4}

/* Cards + grid */
.card{background:var(--card);border:1px solid var(--line);border-radius:10px;padding:18px;box-shadow:0 1px 3px rgba(20,40,70,.06)}
.grid{display:grid;grid-template-columns:repeat(auto-fill,minmax(260px,1fr));gap:16px;margin-top:12px}
.course-card{display:block;color:var(--text)}
.course-card:hover{text-decoration:none;box-shadow:0 4px 14px rgba(20,40,70,.12);transform:translateY(-2px);transition:.15s}
.course-card h3{margin:.1em 0 .3em;color:var(--blue)}
.muted{color:var(--muted);font-size:.9rem}

/* Forms */
.form{max-width:520px;display:flex;flex-direction:column;gap:12px}
.form label{display:flex;flex-direction:column;gap:5px;font-weight:500}
.form input[type=text],.form input[type=email],.form input[type=password],
.form input[type=number],.form textarea,.form select{
  font:inherit;padding:9px 11px;border:1px solid var(--line);border-radius:7px;background:#fff}
.form .check{flex-direction:row;align-items:center;gap:8px;font-weight:400}
button,.btn{background:var(--blue);color:#fff;border:0;border-radius:7px;padding:10px 16px;font:inherit;font-weight:500;cursor:pointer;display:inline-block}
button:hover,.btn:hover{background:#163a5c;text-decoration:none}
.btn.ghost{background:#eef2f7;color:var(--blue)}
.link-danger{background:none;color:var(--accent);padding:0}
.link-danger:hover{background:none;text-decoration:underline}

/* Messages */
.error{background:#fdecea;border-left:4px solid var(--accent);padding:10px 12px;border-radius:6px;color:#8a1f1f}
.notice{background:#e8f4ea;border-left:4px solid #2e7d32;padding:10px 12px;border-radius:6px;color:#1b5e20}

/* Tables */
table.data{width:100%;border-collapse:collapse;background:#fff;border:1px solid var(--line);border-radius:8px;overflow:hidden}
table.data th{background:var(--blue);color:#fff;text-align:left;padding:9px 11px;font-size:.9rem}
table.data td{padding:9px 11px;border-top:1px solid var(--line);font-size:.92rem}
.pill{font-size:.78rem;padding:2px 8px;border-radius:20px}
.pill.on{background:#e2f0e4;color:#1b5e20}
.pill.off{background:#f3e3e3;color:#8a1f1f}

/* Course layout + video */
.course-layout{display:grid;grid-template-columns:1fr 280px;gap:22px;margin-top:16px}
.video-frame{position:relative;padding-bottom:56.25%;height:0;border-radius:10px;overflow:hidden;background:#000}
.video-frame iframe{position:absolute;inset:0;width:100%;height:100%}
.lesson-list ol{list-style:decimal;padding-left:22px}
.lesson-list li{margin:6px 0}
.lesson-list li.current a{font-weight:700;color:var(--blue)}
.locked{text-align:center}

@media(max-width:760px){
  .course-layout{grid-template-columns:1fr}
  .site-header .wrap{flex-direction:column;align-items:flex-start}
}