/* Campus Circle Design System
 * Token layer -> base primitives -> motion -> material -> responsive
 * Loaded after style.css as the authoritative visual layer.
 */
:root {
    color-scheme: light;

    /* Core palette: neutral-first, single JLU blue accent */
    --c-paper: #f4f6f9;
    --c-paper-deep: #e9edf2;
    --c-surface: #ffffff;
    --c-surface-2: #f2f5f8;
    --c-surface-3: #e9eef4;
    --c-ink: #15212e;
    --c-ink-2: #2b3948;
    --c-muted: #667585;
    --c-faint: #8b98a6;
    --c-line: #dfe5ec;
    --c-line-strong: #c7d0da;
    --c-accent: #0033a0;
    --c-accent-hover: #002a85;
    --c-accent-ink: #002566;
    --c-accent-soft: #e8eef9;
    --c-accent-bright: #0033a0;
    --c-danger: #b33a3a;
    --c-danger-soft: #fae7e6;
    --c-success: #2f7a50;
    --c-success-soft: #e6f3ea;
    --c-warning: #8a6116;
    --c-warning-soft: #f7efdc;
    --c-info: #35677a;
    --c-info-soft: #e5eff2;

    /* Legacy aliases so existing component rules keep working */
    --paper: var(--c-paper);
    --paper-deep: var(--c-paper-deep);
    --surface: var(--c-surface);
    --surface-2: var(--c-surface-2);
    --ink: var(--c-ink);
    --ink-2: var(--c-ink-2);
    --muted: var(--c-muted);
    --faint: var(--c-faint);
    --line: var(--c-line);
    --line-strong: var(--c-line-strong);
    --primary: var(--c-accent);
    --primary-hover: var(--c-accent-hover);
    --primary-ink: var(--c-accent-ink);
    --primary-soft: var(--c-accent-soft);
    --primary-bright: var(--c-accent-bright);
    --danger: var(--c-danger);
    --danger-soft: var(--c-danger-soft);
    --success: var(--c-success);
    --success-soft: var(--c-success-soft);
    --amber: var(--c-warning);
    --amber-soft: var(--c-warning-soft);
    --info: var(--c-info);
    --info-soft: var(--c-info-soft);

    /* Spacing scale */
    --sp-1: 4px;
    --sp-2: 8px;
    --sp-3: 12px;
    --sp-4: 16px;
    --sp-5: 20px;
    --sp-6: 24px;
    --sp-8: 32px;
    --sp-10: 40px;
    --sp-12: 48px;

    /* Radius scale */
    --r-xs: 4px;
    --r-sm: 6px;
    --r-md: 8px;
    --r-lg: 12px;
    --r-xl: 16px;
    --r-pill: 999px;

    /* Diffused layered shadows */
    --sh-xs: 0 1px 2px rgba(21, 33, 46, 0.04), 0 1px 1px rgba(21, 33, 46, 0.02);
    --sh-sm: 0 2px 8px rgba(21, 33, 46, 0.05), 0 1px 2px rgba(21, 33, 46, 0.04);
    --sh-md: 0 10px 30px rgba(21, 33, 46, 0.08), 0 2px 8px rgba(21, 33, 46, 0.04);
    --sh-lg: 0 24px 64px rgba(21, 33, 46, 0.12), 0 4px 12px rgba(21, 33, 46, 0.06);

    /* Motion timing and easing */
    --dur-fast: 140ms;
    --dur-base: 220ms;
    --dur-slow: 420ms;
    --ease-out: cubic-bezier(0.16, 1, 0.3, 1);
    --ease-in-out: cubic-bezier(0.77, 0, 0.175, 1);
    --ease-spring: cubic-bezier(0.34, 1.56, 0.64, 1);

    /* Layer order */
    --z-header: 40;
    --z-dropdown: 50;
    --z-modal: 60;
    --z-lightbox: 70;
    --z-toast: 80;

    /* Liquid glass */
    --glass-bg: rgba(255, 255, 255, 0.72);
    --glass-strong: rgba(255, 255, 255, 0.9);
    --glass-border: rgba(255, 255, 255, 0.55);
    --glass-blur: 18px;

    --font-sans: "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", "Noto Sans SC", system-ui, -apple-system, sans-serif;
    --font-mono: ui-monospace, "Cascadia Mono", Consolas, "Courier New", monospace;
}

/* Base primitives */
html {
    scroll-behavior: smooth;
    scroll-padding-top: calc(var(--header-h, 72px) + 24px);
}

body {
    background: var(--c-paper);
    color: var(--c-ink);
    -webkit-font-smoothing: antialiased;
    text-rendering: optimizeLegibility;
}

::selection {
    background: var(--c-accent);
    color: #fff;
}

button,
a,
input,
textarea,
select,
[role="button"] {
    touch-action: manipulation;
    -webkit-tap-highlight-color: transparent;
}

:focus-visible {
    outline: 3px solid rgba(0, 51, 160, 0.28);
    outline-offset: 2px;
}

/* Page enter: calm, one-time, transform + opacity only */
@media (prefers-reduced-motion: no-preference) {
    .page-main {
        animation: dsPageEnter var(--dur-slow) var(--ease-out) both;
    }
    .auth-shell {
        animation: dsPageEnter var(--dur-slow) var(--ease-out) both;
    }
    @keyframes dsPageEnter {
        from { opacity: 0; transform: translateY(12px); }
        to { opacity: 1; transform: none; }
    }
}

/* Card depth: restrained Z lift, excluded on form/chat surfaces */
@media (hover: hover) and (pointer: fine) {
    .card:hover:not(.people-card):not(.side-card):not(.chat-card):not(.modal) {
        transform: translateY(-2px);
        box-shadow: var(--sh-md);
    }
    .people-card:hover {
        box-shadow: var(--sh-md);
    }
    .btn:hover,
    .quick-action:hover,
    .nav-link:hover {
        transform: translateY(-1px);
    }
    .btn:active {
        transform: translateY(0) scale(0.98);
    }
}
@media (hover: none), (pointer: coarse) {
    .card:hover,
    .card:hover::before,
    .card:hover::after,
    .btn:hover,
    .quick-action:hover,
    .nav-link:hover {
        transform: none;
    }
    .card:hover::before,
    .card:hover::after {
        opacity: 0;
    }
}


/* Liquid glass */
.site-header {
    background: linear-gradient(135deg, var(--glass-strong), var(--glass-bg));
    -webkit-backdrop-filter: blur(var(--glass-blur)) saturate(1.2);
    backdrop-filter: blur(var(--glass-blur)) saturate(1.2);
    box-shadow: inset 0 1px 0 rgba(255, 255, 255, 0.7), inset 0 -1px 0 rgba(255, 255, 255, 0.1), var(--sh-sm);
}
.site-header.is-scrolled {
    box-shadow: inset 0 1px 0 rgba(255, 255, 255, 0.7), inset 0 -1px 0 rgba(255, 255, 255, 0.08), var(--sh-md);
}
@supports not ((backdrop-filter: blur(1px)) or (-webkit-backdrop-filter: blur(1px))) {
    .site-header { background: var(--c-surface); }
}
.mention-dropdown,
.site-nav.is-open {
    background: rgba(255, 255, 255, 0.92);
    -webkit-backdrop-filter: blur(16px) saturate(1.2);
    backdrop-filter: blur(16px) saturate(1.2);
}
.modal {
    background: linear-gradient(145deg, rgba(255, 255, 255, 0.96), rgba(255, 255, 255, 0.84));
    border-color: rgba(255, 255, 255, 0.62);
    box-shadow: inset 0 1px 0 rgba(255, 255, 255, 0.86), inset 0 -1px 0 rgba(255, 255, 255, 0.08), var(--sh-lg);
}
.modal-backdrop .modal {
    transition: transform var(--dur-slow) var(--ease-spring), opacity var(--dur-base) var(--ease-out);
}
/* Skeleton and pagination loading */
.skeleton {
    position: relative;
    overflow: hidden;
    background: var(--c-surface-2);
    border-radius: var(--r-md);
}
.skeleton::after {
    content: "";
    position: absolute;
    inset: 0;
    transform: translateX(-100%);
    background: linear-gradient(90deg, transparent, rgba(255, 255, 255, 0.5), transparent);
    animation: dsSkeleton 1.4s var(--ease-in-out) infinite;
}
[data-paginate].is-paginating {
    position: relative;
}
[data-paginate].is-paginating::after {
    content: "";
    position: absolute;
    inset: 0;
    z-index: 5;
    pointer-events: none;
    border-radius: var(--r-lg);
    background: linear-gradient(100deg, transparent 20%, rgba(255, 255, 255, 0.32) 50%, transparent 80%);
    background-size: 220% 100%;
    animation: dsSkeletonSweep 1.1s var(--ease-in-out) infinite;
}
@keyframes dsSkeleton {
    100% { transform: translateX(100%); }
}
@keyframes dsSkeletonSweep {
    from { background-position: 220% 0; }
    to { background-position: -220% 0; }
}
/* Container queries: people list adapts without page-level media */
.people-list {
    container-type: inline-size;
}
@container (max-width: 560px) {
    .people-card {
        flex-wrap: wrap;
        align-items: flex-start;
    }
    .people-card .people-side {
        max-width: 100%;
        flex-basis: 100%;
        justify-content: flex-start;
        margin-top: var(--sp-2);
    }
    .people-tags {
        justify-content: flex-start;
    }
}

/* Touch feel and scroll ergonomics */
.chat-body {
    overscroll-behavior: contain;
}
* {
    scrollbar-width: thin;
    scrollbar-color: var(--c-line-strong) transparent;
}
::-webkit-scrollbar {
    width: 10px;
    height: 10px;
}
::-webkit-scrollbar-thumb {
    background: var(--c-line-strong);
    border: 2px solid var(--c-surface);
    border-radius: var(--r-pill);
}
::-webkit-scrollbar-thumb:hover {
    background: var(--c-faint);
}
::-webkit-scrollbar-track {
    background: transparent;
}
/* Dark theme: token swap, no layout change */
@media (prefers-color-scheme: dark) {
    :root {
        color-scheme: dark;
        --c-paper: #0d131b;
        --c-paper-deep: #141c26;
        --c-surface: #161f2a;
        --c-surface-2: #1b2531;
        --c-surface-3: #202c3a;
        --c-ink: #e7edf4;
        --c-ink-2: #c2cdda;
        --c-muted: #8d9cad;
        --c-faint: #68788a;
        --c-line: #253240;
        --c-line-strong: #34445a;
        --c-accent-ink: #b8ccf0;
        --c-accent-soft: #142440;
        --c-accent-bright: #7ba4ff;
        --c-danger: #ef8b87;
        --c-danger-soft: #3a2024;
        --c-success: #7cc59a;
        --c-success-soft: #1d3528;
        --c-warning: #e0b36a;
        --c-warning-soft: #3a2e1a;
        --c-info: #8bc4d8;
        --c-info-soft: #1c2f3a;
        --sh-xs: 0 1px 2px rgba(0, 0, 0, 0.24), 0 1px 1px rgba(0, 0, 0, 0.16);
        --sh-sm: 0 2px 8px rgba(0, 0, 0, 0.28), 0 1px 2px rgba(0, 0, 0, 0.18);
        --sh-md: 0 10px 30px rgba(0, 0, 0, 0.36), 0 2px 8px rgba(0, 0, 0, 0.22);
        --sh-lg: 0 24px 64px rgba(0, 0, 0, 0.44), 0 4px 12px rgba(0, 0, 0, 0.28);
        --glass-bg: rgba(22, 31, 42, 0.72);
        --glass-strong: rgba(27, 37, 49, 0.92);
    }
    body {
        background: var(--c-paper);
        color: var(--c-ink);
    }
    .site-header {
        background: linear-gradient(135deg, var(--glass-strong), var(--glass-bg));
        box-shadow: inset 0 1px 0 rgba(255, 255, 255, 0.08), inset 0 -1px 0 rgba(255, 255, 255, 0.03), var(--sh-sm);
    }
    .mention-dropdown,
    .site-nav.is-open {
        background: rgba(22, 31, 42, 0.92);
    }
    .modal {
        background: linear-gradient(145deg, rgba(27, 37, 49, 0.96), rgba(22, 31, 42, 0.86));
        border-color: rgba(255, 255, 255, 0.1);
        box-shadow: inset 0 1px 0 rgba(255, 255, 255, 0.08), var(--sh-lg);
    }
    .auth-panel {
        background: linear-gradient(180deg, rgba(27, 37, 49, 0.72), rgba(22, 31, 42, 0) 240px), var(--c-surface);
    }
}

/* Reduced motion: collapse all decorative animation */
@media (prefers-reduced-motion: reduce) {
    .page-main,
    .auth-shell,
    .skeleton::after,
    [data-paginate].is-paginating::after {
        animation: none !important;
    }
    .site-header,
    .modal,
    .mention-dropdown,
    .site-nav.is-open {
        -webkit-backdrop-filter: none;
        backdrop-filter: none;
    }
}
/* App UI refactor: user-facing pages */
.dashboard-grid {
    display: grid;
    grid-template-columns: minmax(0, 1.5fr) minmax(320px, 1fr);
    gap: 24px;
    align-items: stretch;
}
.dashboard-grid > .card {
    min-width: 0;
    height: 100%;
}
.dashboard-grid > .card + .card {
    margin-top: 0;
}
@media (max-width: 900px) {
    .dashboard-grid {
        grid-template-columns: 1fr;
    }
}

.feed-layout {
    grid-template-columns: minmax(0, 1fr) 340px;
    gap: 26px;
}
.feed-side {
    display: grid;
    gap: 18px;
    align-content: start;
}
.rail-card {
    position: relative;
}
.rail-card .section-head {
    margin-bottom: 14px;
}

.directory .filter-bar {
    border-radius: 12px;
}
.directory .list-meta {
    margin-top: 18px;
}

.profile-cover {
    background: linear-gradient(120deg, var(--c-surface), var(--c-accent-soft));
}
.profile-cover .avatar-xl {
    box-shadow: var(--sh-md);
}

.chat-page .chat-card {
    min-height: calc(100dvh - 190px);
    display: flex;
    flex-direction: column;
}
.chat-page .chat-body {
    flex: 1;
}
.chat-page .chat-composer {
    margin-top: auto;
}

.messages-page .conversation-list {
    gap: 12px;
}
.conversation-group-title {
    margin: 18px 0 8px;
    color: var(--c-muted);
    font-size: 13px;
    font-weight: 700;
}
.conversation-group-title:first-child {
    margin-top: 0;
}