:root {
  --bg: #f4f9fa; --card: #fff; --text: #231f20; --muted: #6b7280; --border: #e1e9eb;
  --accent: #49c3d6; --accent-dark: #2fb0c5; --accent-soft: #e4f6f9; --accent-ink: #0f3d45;
  --link: #1789a0; --ink: #231f20; --green-soft: #ecfdf3; --red: #dc2626;
}
* { box-sizing: border-box; }
body { margin: 0; font: 16px/1.5 -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif; background: var(--bg); color: var(--text); }
a { color: var(--link); text-decoration: none; }
a:hover { text-decoration: underline; }
h1 { font-size: 1.8rem; margin: 0 0 .5rem; letter-spacing: -.01em; }
h2 { font-size: 1.2rem; margin: 0 0 .75rem; }
h3 { font-size: 1.05rem; margin: 1.25rem 0 .5rem; }
p { margin: 0 0 .75rem; }
code { background: #eef3f4; padding: .1em .4em; border-radius: 4px; font-size: .95em; }
.muted { color: var(--muted); }
.small { font-size: .85rem; }
.eyebrow { text-transform: uppercase; letter-spacing: .08em; font-size: .75rem; color: var(--link); font-weight: 700; margin-bottom: .25rem; }
.inline { display: inline; }

/* top bar */
.topbar { display: flex; align-items: center; justify-content: space-between; gap: 1rem; padding: .6rem 1.25rem; background: var(--ink); color: #fff; border-bottom: 4px solid var(--accent); flex-wrap: wrap; }
.brand { display: flex; align-items: center; gap: .6rem; color: #fff; font-weight: 700; line-height: 1.15; }
.brand:hover { text-decoration: none; }
.brand img { width: 34px; height: 34px; }
.brand small { display: block; font-weight: 500; font-size: .72rem; color: var(--accent); letter-spacing: .08em; text-transform: uppercase; }
.topbar nav { display: flex; gap: 1.1rem; align-items: center; flex-wrap: wrap; }
.topbar nav a { color: #e5e7eb; font-size: .95rem; }
.topbar nav a:hover { color: var(--accent); text-decoration: none; }
button.link { background: none; border: 0; color: #9ca3af; cursor: pointer; font: inherit; padding: 0; }
button.link:hover { color: var(--accent); }

.page { max-width: 880px; margin: 0 auto; padding: 1.5rem 1.25rem 4rem; }
.card { background: var(--card); border: 1px solid var(--border); border-radius: 12px; padding: 1.25rem; margin-bottom: 1.25rem; }
.card.narrow { max-width: 420px; margin: 1.5rem auto 3rem; }
.card.highlight { border-color: var(--accent); background: var(--accent-soft); }
.cred { display: flex; gap: 1rem; align-items: center; margin: .35rem 0; }
.cred span { width: 90px; color: var(--muted); }
.cred code { font-size: 1.1rem; background: #fff; }

label { display: block; margin-bottom: .9rem; font-weight: 500; }
input:not([type=file]), textarea, select { display: block; width: 100%; margin-top: .3rem; padding: .55rem .7rem; font: inherit; border: 1px solid #cfd8da; border-radius: 8px; background: #fff; color: var(--text); }
input:focus, textarea:focus, select:focus { outline: none; border-color: var(--accent); box-shadow: 0 0 0 3px rgba(73, 195, 214, .3); }
input[type=file] { display: block; margin-top: .3rem; }
textarea { resize: vertical; font-family: inherit; }
.row-form { display: grid; grid-template-columns: 1fr 1fr 1fr auto; gap: .75rem; align-items: end; }
.row-form label { margin-bottom: 0; }
@media (max-width: 720px) { .row-form { grid-template-columns: 1fr; } }

.btn { display: inline-block; padding: .5rem .9rem; border-radius: 8px; border: 1px solid #cfd8da; background: #fff; color: var(--text); font: inherit; cursor: pointer; line-height: 1.3; }
.btn:hover { background: #f1f5f6; border-color: var(--accent); text-decoration: none; }
.btn.primary { background: var(--accent); border-color: var(--accent); color: var(--ink); font-weight: 600; }
.btn.primary:hover { background: var(--accent-dark); border-color: var(--accent-dark); }
.btn.danger { color: var(--red); }
.btn.danger:hover { background: #fef2f2; border-color: #fecaca; }
.btn.small { padding: .25rem .6rem; font-size: .85rem; }
.btn.big { padding: .75rem 1.3rem; font-size: 1.05rem; font-weight: 600; }
.btn:disabled { opacity: .4; cursor: default; }

.flash { padding: .7rem 1rem; border-radius: 8px; margin-bottom: 1rem; }
.flash-success { background: var(--green-soft); color: #166534; border: 1px solid #bbf7d0; }
.flash-error { background: #fef2f2; color: #991b1b; border: 1px solid #fecaca; }

/* login */
.login-hero { text-align: center; margin-top: 1.5rem; }
.login-hero img.house { width: min(420px, 80%); display: block; margin: 0 auto .75rem; }
.login-hero img.logo { width: 56px; height: 56px; margin-bottom: .25rem; }
.login-hero h1 { margin: 0; font-size: 1.4rem; }
.login-hero p { color: var(--muted); }

/* progress */
.bar { height: 14px; background: #e3ecee; border-radius: 99px; overflow: hidden; }
.bar.slim { height: 8px; margin-bottom: .3rem; }
.fill { height: 100%; background: linear-gradient(90deg, var(--accent-dark), var(--accent) 60%, #8fdce8); border-radius: 99px; transition: width .4s ease; }
.progress-card { background: var(--card); border: 1px solid var(--border); border-radius: 12px; padding: 1rem 1.25rem; margin-bottom: 1.5rem; border-left: 5px solid var(--accent); }
.progress-card.done { border-color: var(--accent); background: var(--accent-soft); }
.progress-label { display: flex; justify-content: space-between; margin-bottom: .5rem; }
.progress-label span { color: var(--link); font-weight: 700; }
.course-header { display: flex; justify-content: space-between; align-items: center; gap: 1rem; flex-wrap: wrap; margin-bottom: 1rem; }
.course-hero { display: flex; align-items: flex-end; justify-content: space-between; gap: 1.5rem; margin-bottom: 1.25rem; }
.course-hero img { width: 260px; max-width: 40%; flex-shrink: 0; }
@media (max-width: 600px) { .course-hero img { display: none; } }
.done-art { width: 220px; display: block; margin: .5rem auto 0; }

/* course outline */
.section-block { margin-bottom: 1.5rem; }
.section-block h2 { display: flex; align-items: center; gap: .6rem; }
.num { display: inline-flex; width: 26px; height: 26px; border-radius: 50%; background: var(--ink); color: #fff; font-size: .8rem; align-items: center; justify-content: center; flex-shrink: 0; }
.section-done .num { background: var(--accent); color: var(--ink); }
.lesson-list { list-style: none; margin: 0; padding: 0; background: var(--card); border: 1px solid var(--border); border-radius: 12px; overflow: hidden; }
.lesson-list li { border-top: 1px solid var(--border); }
.lesson-list li:first-child { border-top: 0; }
.lesson-list a, .lesson-list .row { display: flex; align-items: center; gap: .75rem; padding: .7rem 1rem; color: var(--text); }
.lesson-list a:hover { background: var(--accent-soft); text-decoration: none; }
.lesson-title { flex: 1; }
.check { width: 24px; height: 24px; border-radius: 50%; border: 2px solid #c5d3d6; display: inline-flex; align-items: center; justify-content: center; font-size: .8rem; flex-shrink: 0; font-weight: 700; }
.completed .check { background: var(--accent); border-color: var(--accent); color: var(--ink); }
.completed .lesson-title { color: var(--muted); }
.pill { font-size: .72rem; background: var(--accent-soft); color: var(--accent-ink); border: 1px solid #b6e6ee; padding: .1rem .5rem; border-radius: 99px; font-weight: 700; }
.pill.next { background: var(--accent); color: var(--ink); border-color: var(--accent); }

/* lesson page */
.lesson-nav-top { display: flex; justify-content: space-between; margin-bottom: .5rem; flex-wrap: wrap; gap: .5rem; }
.lesson { background: var(--card); border: 1px solid var(--border); border-radius: 12px; padding: 1.5rem; margin-top: 1rem; }
.lesson h1 { display: flex; align-items: center; gap: .6rem; flex-wrap: wrap; }
.video-wrap { margin: 1rem 0 1.25rem; }
.video-wrap video { width: 100%; max-height: 70vh; background: #000; border-radius: 10px; }
.video-wrap.embed { position: relative; padding-top: 56.25%; }
.video-wrap.embed iframe { position: absolute; inset: 0; width: 100%; height: 100%; border: 0; border-radius: 10px; }
.instructions { margin: 1rem 0; }
.instructions h3 { color: var(--accent-ink); }
.instructions ul, .instructions ol { padding-left: 1.4rem; }
.instructions li { margin-bottom: .3rem; }
.file-list { list-style: none; padding: 0; margin: 0 0 1rem; }
.file-list li { padding: .45rem 0; border-bottom: 1px solid var(--border); display: flex; gap: .6rem; align-items: center; flex-wrap: wrap; }
.file-list li:last-child { border-bottom: 0; }
.complete-box { margin-top: 1.5rem; padding: 1rem; background: var(--accent-soft); border-radius: 10px; display: flex; align-items: center; gap: 1rem; }
.complete-box form { display: flex; align-items: center; gap: 1rem; flex-wrap: wrap; }
.complete-box.admin-note { color: var(--muted); background: var(--bg); }
.lesson-nav { display: flex; justify-content: space-between; margin-top: 1.25rem; gap: 1rem; }

/* admin */
.table-wrap { overflow-x: auto; }
table { width: 100%; border-collapse: collapse; }
th, td { text-align: left; padding: .6rem .5rem; border-bottom: 1px solid var(--border); vertical-align: middle; }
th { font-size: .8rem; color: var(--muted); text-transform: uppercase; letter-spacing: .04em; }
.actions { display: inline-flex; gap: .35rem; flex-wrap: wrap; align-items: center; }
.section-admin { border-left: 5px solid var(--accent); }
.section-admin-head { display: flex; justify-content: space-between; align-items: center; gap: 1rem; flex-wrap: wrap; margin-bottom: .75rem; }
.title-form { display: flex; align-items: center; gap: .5rem; flex: 1; }
.title-form input { margin: 0; font-weight: 600; max-width: 380px; }
.lesson-list.admin .row { padding: .55rem .9rem; }
.add-lesson { display: flex; gap: .5rem; margin-top: .75rem; }
.add-lesson input { margin: 0; max-width: 360px; }
.empty-state { text-align: center; padding: 1rem 0; }
.empty-state img { width: 220px; display: block; margin: 0 auto .5rem; }