/* =============================================================================
 * AiProfessor — global design system
 * Blue corporate theme, light + dark. Pages use semantic HTML, so styling the
 * base elements here restyles the whole app; utility/component classes layer on
 * top. No external assets (CSP-safe): system font stack, inline SVG icons.
 * ========================================================================== */

/* ---- Design tokens ------------------------------------------------------- */
:root {
    color-scheme: light;

    /* Brand — vivid blue */
    --brand-50: #eff6ff;
    --brand-100: #dbeafe;
    --brand-200: #bfdbfe;
    --brand-500: #3b82f6;
    --brand-600: #2563eb;
    --brand-700: #1d4ed8;
    --brand-800: #1e40af;

    --accent: var(--brand-600);
    --accent-hover: var(--brand-700);
    --accent-contrast: #ffffff;
    --accent-soft: var(--brand-50);
    --ring: rgba(37, 99, 235, 0.35);

    /* Neutrals — light */
    --bg: #f4f7fb;
    --bg-elevated: #ffffff;
    --surface: #ffffff;
    --surface-2: #f8fafc;
    --sidebar-bg: #0c1a30;
    --sidebar-fg: #c7d2e3;
    --sidebar-fg-strong: #ffffff;
    --sidebar-active: #2563eb;
    --sidebar-hover: rgba(255, 255, 255, 0.08);

    --text: #0f172a;
    --text-muted: #5b6b82;
    --border: #e4e9f2;
    --border-strong: #cdd6e4;

    /* Status */
    --ok: #16a34a;
    --ok-soft: #dcfce7;
    --warn: #d97706;
    --warn-soft: #fef3c7;
    --danger: #dc2626;
    --danger-soft: #fee2e2;
    --info: #2563eb;
    --info-soft: #dbeafe;

    /* Shape & depth */
    --radius-sm: 8px;
    --radius: 12px;
    --radius-lg: 18px;
    --shadow-sm: 0 1px 2px rgba(15, 23, 42, 0.06), 0 1px 3px rgba(15, 23, 42, 0.05);
    --shadow: 0 4px 12px rgba(15, 23, 42, 0.08), 0 2px 4px rgba(15, 23, 42, 0.04);
    --shadow-lg: 0 12px 32px rgba(15, 23, 42, 0.14);

    /* Metrics */
    --sidebar-w: 256px;
    --topbar-h: 60px;
    --content-max: 1160px;

    --font: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial,
        "Apple Color Emoji", "Segoe UI Emoji", sans-serif;
    --mono: ui-monospace, SFMono-Regular, "SF Mono", Menlo, Consolas, monospace;
}

@media (prefers-color-scheme: dark) {
    :root:not([data-theme="light"]) {
        color-scheme: dark;
        --accent: var(--brand-500);
        --accent-hover: #60a5fa;
        --accent-soft: rgba(59, 130, 246, 0.14);
        --ring: rgba(59, 130, 246, 0.45);

        --bg: #0a1120;
        --bg-elevated: #101a2e;
        --surface: #101a2e;
        --surface-2: #0d1526;
        --sidebar-bg: #070e1c;
        --sidebar-fg: #9fb0c9;
        --sidebar-fg-strong: #ffffff;
        --sidebar-hover: rgba(255, 255, 255, 0.06);

        --text: #e6edf7;
        --text-muted: #93a3bd;
        --border: #1e2b44;
        --border-strong: #2a3a58;

        --ok-soft: rgba(22, 163, 74, 0.16);
        --warn-soft: rgba(217, 119, 6, 0.18);
        --danger-soft: rgba(220, 38, 38, 0.18);
        --info-soft: rgba(37, 99, 235, 0.2);
        --shadow-sm: 0 1px 2px rgba(0, 0, 0, 0.4);
        --shadow: 0 6px 18px rgba(0, 0, 0, 0.45);
        --shadow-lg: 0 16px 40px rgba(0, 0, 0, 0.55);
    }
}

/* Manual dark toggle wins over the media query in both directions. */
:root[data-theme="dark"] {
    color-scheme: dark;
    --accent: var(--brand-500);
    --accent-hover: #60a5fa;
    --accent-soft: rgba(59, 130, 246, 0.14);
    --ring: rgba(59, 130, 246, 0.45);
    --bg: #0a1120;
    --bg-elevated: #101a2e;
    --surface: #101a2e;
    --surface-2: #0d1526;
    --sidebar-bg: #070e1c;
    --sidebar-fg: #9fb0c9;
    --sidebar-fg-strong: #ffffff;
    --sidebar-hover: rgba(255, 255, 255, 0.06);
    --text: #e6edf7;
    --text-muted: #93a3bd;
    --border: #1e2b44;
    --border-strong: #2a3a58;
    --ok-soft: rgba(22, 163, 74, 0.16);
    --warn-soft: rgba(217, 119, 6, 0.18);
    --danger-soft: rgba(220, 38, 38, 0.18);
    --info-soft: rgba(37, 99, 235, 0.2);
    --shadow-sm: 0 1px 2px rgba(0, 0, 0, 0.4);
    --shadow: 0 6px 18px rgba(0, 0, 0, 0.45);
    --shadow-lg: 0 16px 40px rgba(0, 0, 0, 0.55);
}

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

html {
    -webkit-text-size-adjust: 100%;
    text-size-adjust: 100%;
}

body {
    margin: 0;
    font-family: var(--font);
    font-size: 15px;
    line-height: 1.6;
    color: var(--text);
    background: var(--bg);
    -webkit-font-smoothing: antialiased;
    text-rendering: optimizeLegibility;
}

h1, h2, h3, h4 {
    color: var(--text);
    line-height: 1.25;
    font-weight: 700;
    letter-spacing: -0.01em;
    margin: 0 0 0.6em;
}

h1 { font-size: 1.7rem; }
h2 { font-size: 1.3rem; margin-top: 1.6rem; }
h3 { font-size: 1.08rem; }

h1:focus { outline: none; }

p { margin: 0 0 1rem; }

a {
    color: var(--accent);
    text-decoration: none;
    font-weight: 500;
    transition: color 0.15s ease;
}

a:hover { color: var(--accent-hover); text-decoration: underline; }

hr {
    border: none;
    border-top: 1px solid var(--border);
    margin: 1.5rem 0;
}

code, kbd, samp { font-family: var(--mono); font-size: 0.9em; }

strong { font-weight: 650; }

::selection { background: var(--accent-soft); }

:focus-visible {
    outline: 2px solid var(--accent);
    outline-offset: 2px;
    border-radius: 4px;
}

/* ---- Content wrappers ---------------------------------------------------- */
.page {
    max-width: var(--content-max);
    margin: 0 auto;
    padding: 2rem 1.75rem 3rem;
}

.page-header {
    display: flex;
    flex-wrap: wrap;
    align-items: center;
    justify-content: space-between;
    gap: 1rem;
    margin-bottom: 1.5rem;
}

.page-header h1 { margin: 0; }

.muted { color: var(--text-muted); }
.text-sm { font-size: 0.875rem; }

/* ---- Cards & panels ------------------------------------------------------ */
.card,
.panel {
    background: var(--surface);
    border: 1px solid var(--border);
    border-radius: var(--radius);
    box-shadow: var(--shadow-sm);
}

.card { padding: 1.25rem 1.4rem; }
.card + .card,
.card + .panel { margin-top: 1.15rem; }

.card-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(230px, 1fr));
    gap: 1.1rem;
}

/* Stat tile */
.stat {
    background: var(--surface);
    border: 1px solid var(--border);
    border-radius: var(--radius);
    padding: 1.1rem 1.25rem;
    box-shadow: var(--shadow-sm);
}

.stat .stat-label {
    font-size: 0.78rem;
    text-transform: uppercase;
    letter-spacing: 0.04em;
    color: var(--text-muted);
    font-weight: 600;
}

.stat .stat-value {
    font-size: 1.8rem;
    font-weight: 750;
    letter-spacing: -0.02em;
    margin-top: 0.15rem;
}

/* ---- Tables -------------------------------------------------------------- */
table {
    width: 100%;
    border-collapse: separate;
    border-spacing: 0;
    background: var(--surface);
    border: 1px solid var(--border);
    border-radius: var(--radius);
    overflow: hidden;
    box-shadow: var(--shadow-sm);
    margin: 0 0 1.25rem;
    font-size: 0.925rem;
}

thead th {
    text-align: left;
    font-size: 0.74rem;
    letter-spacing: 0.05em;
    text-transform: uppercase;
    color: var(--text-muted);
    font-weight: 650;
    background: var(--surface-2);
    padding: 0.7rem 1rem;
    border-bottom: 1px solid var(--border);
    white-space: nowrap;
}

tbody td {
    padding: 0.8rem 1rem;
    border-bottom: 1px solid var(--border);
    vertical-align: middle;
}

tbody tr:last-child td { border-bottom: none; }
tbody tr { transition: background 0.12s ease; }
tbody tr:hover { background: var(--surface-2); }

/* ---- Buttons ------------------------------------------------------------- */
button,
.btn,
input[type="submit"],
input[type="button"] {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: 0.45rem;
    font-family: inherit;
    font-size: 0.9rem;
    font-weight: 600;
    line-height: 1.2;
    padding: 0.55rem 1rem;
    border-radius: var(--radius-sm);
    border: 1px solid var(--accent);
    background: var(--accent);
    color: var(--accent-contrast);
    cursor: pointer;
    transition: background 0.15s ease, border-color 0.15s ease, transform 0.05s ease, box-shadow 0.15s ease;
    text-decoration: none;
}

button:hover,
.btn:hover,
input[type="submit"]:hover {
    background: var(--accent-hover);
    border-color: var(--accent-hover);
    color: var(--accent-contrast);
    text-decoration: none;
}

button:active,
.btn:active { transform: translateY(1px); }

button:disabled,
.btn:disabled,
button[disabled] {
    opacity: 0.55;
    cursor: not-allowed;
    transform: none;
}

/* Secondary / ghost / danger variants */
.btn-secondary,
button.secondary {
    background: var(--surface);
    color: var(--text);
    border-color: var(--border-strong);
}

.btn-secondary:hover,
button.secondary:hover {
    background: var(--surface-2);
    color: var(--text);
    border-color: var(--accent);
}

.btn-ghost {
    background: transparent;
    color: var(--accent);
    border-color: transparent;
}

.btn-ghost:hover { background: var(--accent-soft); color: var(--accent-hover); }

.btn-danger,
button.danger {
    background: var(--danger);
    border-color: var(--danger);
}

.btn-danger:hover,
button.danger:hover { background: #b91c1c; border-color: #b91c1c; }

.btn-sm { padding: 0.35rem 0.7rem; font-size: 0.82rem; }

/* ---- Forms --------------------------------------------------------------- */
label {
    display: inline-block;
    font-weight: 600;
    font-size: 0.85rem;
    color: var(--text);
    margin-bottom: 0.35rem;
}

input:not([type="checkbox"]):not([type="radio"]):not([type="submit"]):not([type="button"]),
select,
textarea,
.form-control {
    width: 100%;
    max-width: 100%;
    font-family: inherit;
    font-size: 0.92rem;
    color: var(--text);
    background: var(--bg-elevated);
    border: 1px solid var(--border-strong);
    border-radius: var(--radius-sm);
    padding: 0.55rem 0.7rem;
    transition: border-color 0.15s ease, box-shadow 0.15s ease;
}

input:focus,
select:focus,
textarea:focus,
.form-control:focus {
    outline: none;
    border-color: var(--accent);
    box-shadow: 0 0 0 3px var(--ring);
}

textarea { min-height: 6rem; resize: vertical; }

.field { margin-bottom: 1rem; }

.form-narrow { max-width: 440px; }

/* Blazor validation */
.valid.modified:not([type=checkbox]) { border-color: var(--ok); }
.invalid { border-color: var(--danger); }
.validation-message { color: var(--danger); font-size: 0.82rem; margin-top: 0.25rem; }

/* ---- Badges / pills ------------------------------------------------------ */
.badge {
    display: inline-flex;
    align-items: center;
    gap: 0.3rem;
    font-size: 0.74rem;
    font-weight: 650;
    letter-spacing: 0.02em;
    padding: 0.18rem 0.55rem;
    border-radius: 999px;
    background: var(--surface-2);
    color: var(--text-muted);
    border: 1px solid var(--border);
    text-transform: capitalize;
}

.badge-ok { background: var(--ok-soft); color: var(--ok); border-color: transparent; }
.badge-warn { background: var(--warn-soft); color: var(--warn); border-color: transparent; }
.badge-danger { background: var(--danger-soft); color: var(--danger); border-color: transparent; }
.badge-info { background: var(--info-soft); color: var(--info); border-color: transparent; }

/* ---- Alerts -------------------------------------------------------------- */
.alert {
    border: 1px solid var(--border);
    border-left-width: 4px;
    border-radius: var(--radius-sm);
    padding: 0.8rem 1rem;
    margin: 0 0 1rem;
    background: var(--surface);
}

.alert-info { border-left-color: var(--info); background: var(--info-soft); }
.alert-success { border-left-color: var(--ok); background: var(--ok-soft); }
.alert-warning { border-left-color: var(--warn); background: var(--warn-soft); }
.alert-danger { border-left-color: var(--danger); background: var(--danger-soft); }

/* ---- Quick-links (home) -------------------------------------------------- */
.quick-links {
    display: flex;
    flex-wrap: wrap;
    gap: 0.75rem;
    margin-top: 1rem;
}

.quick-links a {
    display: inline-flex;
    align-items: center;
    gap: 0.5rem;
    padding: 0.7rem 1.1rem;
    background: var(--surface);
    border: 1px solid var(--border);
    border-radius: var(--radius);
    font-weight: 600;
    color: var(--text);
    box-shadow: var(--shadow-sm);
    transition: border-color 0.15s ease, box-shadow 0.15s ease, transform 0.08s ease;
}

.quick-links a:hover {
    text-decoration: none;
    border-color: var(--accent);
    color: var(--accent);
    box-shadow: var(--shadow);
    transform: translateY(-1px);
}

/* ---- Empty state --------------------------------------------------------- */
.empty {
    text-align: center;
    color: var(--text-muted);
    padding: 2.5rem 1rem;
    border: 1px dashed var(--border-strong);
    border-radius: var(--radius);
    background: var(--surface-2);
}

/* ---- Blazor error UI ----------------------------------------------------- */
.blazor-error-boundary {
    background: var(--danger);
    padding: 1rem 1rem 1rem 1rem;
    color: white;
    border-radius: var(--radius-sm);
}

.blazor-error-boundary::after { content: "An error has occurred."; }

/* =============================================================================
 * App shell — sidebar + topbar
 * ========================================================================== */
.app-shell { min-height: 100vh; }
.nav-toggle { position: absolute; opacity: 0; pointer-events: none; }
.nav-scrim { display: none; }

/* ---- Sidebar ------------------------------------------------------------- */
.sidebar {
    position: fixed;
    inset: 0 auto 0 0;
    width: var(--sidebar-w);
    background: var(--sidebar-bg);
    color: var(--sidebar-fg);
    display: flex;
    flex-direction: column;
    gap: 0.35rem;
    padding: 1rem 0.85rem 1.5rem;
    z-index: 40;
    overflow-y: auto;
}

.sidebar .brand {
    display: flex;
    align-items: center;
    gap: 0.65rem;
    padding: 0.55rem 0.5rem 1.1rem;
    color: var(--sidebar-fg-strong);
    font-weight: 600;
}

.sidebar .brand:hover { text-decoration: none; color: var(--sidebar-fg-strong); }

.brand-mark {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    width: 34px;
    height: 34px;
    border-radius: 10px;
    background: linear-gradient(135deg, var(--brand-500), var(--brand-700));
    color: #fff;
    box-shadow: 0 4px 12px rgba(37, 99, 235, 0.45);
    flex: none;
}

.brand-name { font-size: 1.12rem; letter-spacing: -0.01em; }
.brand-name strong { font-weight: 750; }

.side-nav { display: flex; flex-direction: column; gap: 0.15rem; }

.nav-section {
    font-size: 0.68rem;
    text-transform: uppercase;
    letter-spacing: 0.08em;
    color: color-mix(in srgb, var(--sidebar-fg) 65%, transparent);
    font-weight: 700;
    margin: 1rem 0.65rem 0.35rem;
}

.nav-link {
    display: flex;
    align-items: center;
    gap: 0.7rem;
    padding: 0.6rem 0.7rem;
    border-radius: 9px;
    color: var(--sidebar-fg);
    font-weight: 550;
    font-size: 0.92rem;
    transition: background 0.14s ease, color 0.14s ease;
}

.nav-link:hover {
    background: var(--sidebar-hover);
    color: var(--sidebar-fg-strong);
    text-decoration: none;
}

.nav-link.active {
    background: linear-gradient(135deg, var(--brand-600), var(--brand-500));
    color: #fff;
    box-shadow: 0 4px 14px rgba(37, 99, 235, 0.4);
}

.nav-link .ico { display: inline-flex; opacity: 0.9; }
.nav-link.active .ico { opacity: 1; }

/* ---- Main column & topbar ------------------------------------------------ */
.app-main {
    margin-left: var(--sidebar-w);
    display: flex;
    flex-direction: column;
    min-height: 100vh;
}

.topbar {
    position: sticky;
    top: 0;
    z-index: 30;
    display: flex;
    align-items: center;
    gap: 0.6rem;
    height: var(--topbar-h);
    padding: 0 1.25rem;
    background: color-mix(in srgb, var(--bg-elevated) 88%, transparent);
    -webkit-backdrop-filter: blur(8px);
    backdrop-filter: blur(8px);
    border-bottom: 1px solid var(--border);
}

.topbar-spacer { flex: 1; }
.topbar-brand { display: none; font-size: 1.05rem; color: var(--text); }
.nav-burger { display: none; }

.icon-btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    width: 38px;
    height: 38px;
    padding: 0;
    border-radius: 10px;
    background: transparent;
    color: var(--text-muted);
    border: 1px solid transparent;
    cursor: pointer;
}

.icon-btn:hover {
    background: var(--surface-2);
    color: var(--text);
    border-color: var(--border);
}

/* Theme toggle icon swap */
.theme-toggle .ico-sun { display: none; }
.theme-toggle .ico-moon { display: inline-flex; }
@media (prefers-color-scheme: dark) {
    :root:not([data-theme="light"]) .theme-toggle .ico-sun { display: inline-flex; }
    :root:not([data-theme="light"]) .theme-toggle .ico-moon { display: none; }
}
:root[data-theme="dark"] .theme-toggle .ico-sun { display: inline-flex; }
:root[data-theme="dark"] .theme-toggle .ico-moon { display: none; }
:root[data-theme="light"] .theme-toggle .ico-sun { display: none; }
:root[data-theme="light"] .theme-toggle .ico-moon { display: inline-flex; }

/* ---- User menu ----------------------------------------------------------- */
.user-menu { position: relative; }
.user-menu > summary {
    list-style: none;
    display: inline-flex;
    align-items: center;
    gap: 0.55rem;
    padding: 0.3rem 0.55rem 0.3rem 0.35rem;
    border-radius: 999px;
    border: 1px solid var(--border);
    background: var(--surface);
    cursor: pointer;
    color: var(--text);
    max-width: 220px;
}

.user-menu > summary::-webkit-details-marker { display: none; }
.user-menu > summary:hover { border-color: var(--accent); }

.avatar {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    width: 30px;
    height: 30px;
    border-radius: 50%;
    background: linear-gradient(135deg, var(--brand-500), var(--brand-700));
    color: #fff;
    font-size: 0.75rem;
    font-weight: 700;
    flex: none;
}

.user-menu .user-name {
    font-size: 0.88rem;
    font-weight: 600;
    max-width: 130px;
    overflow: hidden;
    text-overflow: ellipsis;
    white-space: nowrap;
}

.user-menu .chev { color: var(--text-muted); }

.menu-pop {
    position: absolute;
    right: 0;
    top: calc(100% + 8px);
    min-width: 180px;
    background: var(--surface);
    border: 1px solid var(--border);
    border-radius: var(--radius);
    box-shadow: var(--shadow-lg);
    padding: 0.35rem;
    display: flex;
    flex-direction: column;
}

.menu-pop a {
    padding: 0.5rem 0.7rem;
    border-radius: 8px;
    color: var(--text);
    font-weight: 500;
    font-size: 0.9rem;
}

.menu-pop a:hover { background: var(--surface-2); color: var(--accent); text-decoration: none; }

/* ---- Content ------------------------------------------------------------- */
.content {
    flex: 1;
    width: 100%;
    max-width: var(--content-max);
    margin: 0 auto;
    padding: 1.9rem 1.75rem 3.5rem;
}

/* ---- Responsive ---------------------------------------------------------- */
@media (max-width: 960px) {
    .sidebar {
        transform: translateX(-100%);
        transition: transform 0.22s ease;
        box-shadow: var(--shadow-lg);
    }
    .nav-toggle:checked ~ .sidebar { transform: none; }
    .nav-toggle:checked ~ .nav-scrim {
        display: block;
        position: fixed;
        inset: 0;
        background: rgba(4, 10, 22, 0.5);
        z-index: 35;
    }
    .app-main { margin-left: 0; }
    .nav-burger { display: inline-flex; }
    .topbar-brand { display: inline-flex; }
}

@media (max-width: 720px) {
    .content { padding: 1.25rem 1rem 2.5rem; }
    table { display: block; overflow-x: auto; white-space: nowrap; }
    h1 { font-size: 1.45rem; }
    .user-menu .user-name { display: none; }
}