*, *::before, *::after { box-sizing: border-box; }

html, body { height: 100%; margin: 0; }

body {
    display: flex;
    flex-direction: column;
    background: var(--c-bg);
    color: var(--c-text);
    font-family: system-ui, -apple-system, "Segoe UI", Roboto, sans-serif;
    line-height: 1.5;
}

:root {
    --c-bg: #f8fafc;
    --c-surface: #ffffff;
    --c-text: #0f172a;
    --c-text-muted: #64748b;
    --c-text-link: #6366f1;
    --c-text-link-hover: #4f46e5;
    --c-border: #e2e8f0;
    --c-accent: #6366f1;
    --c-badge-ok-bg: #dcfce7;
    --c-badge-ok-text: #166534;
    --c-badge-warn-bg: #fef3c7;
    --c-badge-warn-text: #92400e;
}

[data-theme="dark"] {
    --c-bg: #0f1115;
    --c-surface: #171a21;
    --c-text: #e7e9ee;
    --c-text-muted: #9aa3b2;
    --c-text-link: #6ea8fe;
    --c-text-link-hover: #8bb9fe;
    --c-border: #262b36;
    --c-accent: #6ea8fe;
    --c-badge-ok-bg: rgba(16, 185, 129, 0.15);
    --c-badge-ok-text: #6ee7b7;
    --c-badge-warn-bg: rgba(251, 191, 36, 0.15);
    --c-badge-warn-text: #fcd34d;
}

a { color: var(--c-text-link); }
a:hover { color: var(--c-text-link-hover); }

/* Layout */
.page { display: flex; flex-direction: column; min-height: 100vh; }
.page-header { position: sticky; top: 0; z-index: 10; border-bottom: 1px solid var(--c-border); background: var(--c-surface); }
.page-header-inner { max-width: 1152px; margin: 0 auto; display: flex; align-items: center; justify-content: space-between; padding: 0.75rem 1.5rem; }
.page-main { flex: 1; width: 100%; max-width: 1152px; margin: 0 auto; padding: 2rem 1.5rem; }
.page-footer { border-top: 1px solid var(--c-border); padding: 1rem; text-align: center; font-size: 0.75rem; color: var(--c-text-muted); }

/* Nav */
.nav { display: flex; align-items: center; gap: 1rem; font-size: 0.875rem; }
.nav-link { color: var(--c-text-link); text-decoration: none; }
.nav-link:hover { color: var(--c-text-link-hover); }
.nav-sep { color: var(--c-text-muted); }
.logo { font-size: 1.125rem; font-weight: 600; color: var(--c-text); text-decoration: none; }

/* Buttons */
.btn {
    display: inline-flex; align-items: center; justify-content: center; gap: 0.5rem;
    border-radius: 0.5rem; padding: 0.5rem 1rem; font-size: 0.875rem; font-weight: 500;
    border: none; cursor: pointer; transition: opacity 0.15s;
}
.btn:active { opacity: 0.8; }
.btn-sm { padding: 0.25rem 0.5rem; font-size: 0.75rem; }
.btn-primary { background: var(--c-accent); color: white; text-decoration: none; }
.btn-primary:hover { opacity: 0.9; }
.btn-secondary {
    background: var(--c-surface); color: var(--c-text); text-decoration: none;
    box-shadow: inset 0 0 0 1px var(--c-border);
}
.btn-secondary:hover { background: var(--c-border); }

/* Forms */
.input {
    width: 100%; border-radius: 0.5rem; background: var(--c-bg); color: var(--c-text);
    padding: 0.5rem 0.75rem; font-size: 0.875rem; border: 1px solid var(--c-border);
    outline: none;
}
.input:focus { border-color: var(--c-accent); box-shadow: 0 0 0 2px rgba(99, 102, 241, 0.2); }
.input::placeholder { color: var(--c-text-muted); }
.label { display: block; margin-bottom: 0.25rem; font-size: 0.875rem; font-weight: 500; }
.hint { margin-top: 0.25rem; font-size: 0.75rem; color: var(--c-text-muted); }

/* Cards */
.card { border-radius: 0.75rem; background: var(--c-surface); border: 1px solid var(--c-border); }
.card-flush { border-radius: 0.75rem; background: var(--c-surface); border: 1px solid var(--c-border); padding: 0; }
.card-body { padding: 1.5rem; }

/* Grid */
.grid { display: grid; gap: 1rem; }
.grid-2 { grid-template-columns: repeat(auto-fill, minmax(22rem, 1fr)); }
.grid-stats { grid-template-columns: repeat(auto-fill, minmax(12rem, 1fr)); }

/* Typography */
.page-title { margin: 0 0 1.5rem; font-size: 1.5rem; font-weight: 600; }
.section-title { margin: 0 0 0.75rem; font-size: 1.125rem; font-weight: 500; }
.stat-value { margin: 0.5rem 0 0; font-size: 1.875rem; font-weight: 600; }
.stat-title { font-size: 0.875rem; color: var(--c-text-muted); margin: 0; }
.text-muted { color: var(--c-text-muted); }
.opacity-30 { opacity: 0.3; }
.text-center { text-align: center; }
.text-sm { font-size: 0.875rem; }
.font-mono { font-family: monospace; }

/* Spacing */
.mt-1 { margin-top: 0.25rem; }
.mt-2 { margin-top: 0.5rem; }
.mt-4 { margin-top: 1rem; }
.mt-6 { margin-top: 1.5rem; }
.mt-8 { margin-top: 2rem; }
.mb-2 { margin-bottom: 0.5rem; }
.mb-4 { margin-bottom: 1rem; }
.mb-6 { margin-bottom: 1.5rem; }
.ml-2 { margin-left: 0.5rem; }
.p-0 { padding: 0; }
.p-4 { padding: 1rem; }
.p-6 { padding: 1.5rem; }
.px-6 { padding-left: 1.5rem; padding-right: 1.5rem; }
.py-3 { padding-top: 0.75rem; padding-bottom: 0.75rem; }
.gap-2 { gap: 0.5rem; }
.gap-4 { gap: 1rem; }

/* Flex */
.flex { display: flex; }
.flex-wrap { flex-wrap: wrap; }
.items-center { align-items: center; }
.justify-between { justify-content: space-between; }
.w-full { width: 100%; }
.overflow-x-auto { overflow-x: auto; }

/* Badges */
.badge { display: inline-flex; align-items: center; border-radius: 9999px; padding: 0.125rem 0.625rem; font-size: 0.75rem; font-weight: 500; }
.badge-ok { background: var(--c-badge-ok-bg); color: var(--c-badge-ok-text); }
.badge-warn { background: var(--c-badge-warn-bg); color: var(--c-badge-warn-text); }

/* Tables */
table { width: 100%; font-size: 0.875rem; border-collapse: collapse; }
th { text-align: left; font-weight: 500; color: var(--c-text-muted); padding: 0.75rem 1.5rem; border-bottom: 1px solid var(--c-border); }
td { padding: 0.75rem 1.5rem; border-bottom: 1px solid var(--c-border); }
tr:last-child td { border-bottom: none; }

/* Alerts */
.alert { padding: 0.75rem 1rem; border-radius: 0.5rem; font-size: 0.875rem; margin-bottom: 1rem; }
.alert-error { background: #fef2f2; color: #991b1b; }
.alert-success { background: #dcfce7; color: #166534; }
.alert-warning { background: #fef3c7; color: #92400e; }

.ml-2 { margin-left: 0.5rem; }
.list-pad { padding-left: 1.25rem; }
.import-card { border-color: rgba(16,185,129,0.4); }
.mini-alert { padding: 0.5rem 0.75rem; border-radius: 0.25rem; margin-bottom: 0.5rem; }
.font-semibold { font-weight: 600; }

/* Theme toggle */
.theme-btn { padding: 0.25rem 0.5rem; font-size: 0.75rem; }

/* Group assignment page */
.group-title { margin: 0 0 0.5rem; font-size: 1rem; font-weight: 600; }
.inline-form { display: inline-flex; align-items: center; gap: 0.375rem; margin: 0; }
.inline-form .input-sm { width: auto; min-width: 10rem; }
.input-sm { padding: 0.25rem 0.5rem; font-size: 0.8125rem; }
.input-score { width: 4.5rem; }
.filter-select { width: auto; }
.hidden { display: none !important; }

/* Markdown body */
.md-body { font-size: 0.9375rem; }
.md-body h1, .md-body h2, .md-body h3 { margin: 1rem 0 0.5rem; line-height: 1.3; }
.md-body h1 { font-size: 1.25rem; }
.md-body h2 { font-size: 1.125rem; }
.md-body p, .md-body ul, .md-body ol { margin: 0.5rem 0; }
.md-body ul, .md-body ol { padding-left: 1.5rem; }
.md-body pre { background: var(--c-bg); border: 1px solid var(--c-border); border-radius: 0.5rem; padding: 0.75rem 1rem; overflow-x: auto; font-size: 0.8125rem; }
.md-body code { font-family: monospace; }
.md-body details.spoiler { border: 1px solid var(--c-border); border-radius: 0.5rem; padding: 0.5rem 0.75rem; margin: 0.5rem 0; }
.md-body details.spoiler summary { cursor: pointer; font-weight: 500; color: var(--c-text-link); }
.md-body img { max-width: 100%; }
.md-body table { margin: 0.5rem 0; }

/* Empty state */
.empty { text-align: center; color: var(--c-text-muted); padding: 1.5rem; }

/* Mono inline code */
code.code { padding: 0.125rem 0.5rem; border-radius: 0.25rem; font-family: monospace; background: var(--c-bg); }

/* Containers */
.container-sm { max-width: 28rem; margin: 0 auto; }
.form-stack { display: flex; flex-direction: column; gap: 1rem; }
.form-card { padding: 1.5rem; }

/* Header logo */
.link-inherit { font-size: 0.875rem; }