/* ======================== */
/*  Design Tokens           */
/* ======================== */
:root {
    --color-primary: #1877F2;
    --color-primary-hover: #1565C0;
    --color-bg: #F0F2F5;
    --color-surface: #FFFFFF;
    --color-text: #1C1E21;
    --color-text-secondary: #65676B;
    --color-border: #CED0D4;
    --color-shadow: rgba(0, 0, 0, 0.08);
    --radius-card: 12px;
    --radius-chip: 20px;
    --radius-input: 24px;
    --feed-max-width: 600px;
    --header-height: 60px;
    --filters-height: 52px;
    --font-family: 'DM Sans', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
    --transition-fast: 0.2s ease;
    --transition-normal: 0.3s ease;

    /* Document icon colors */
    --color-pdf: #E53935;
    --color-doc: #1565C0;
    --color-xls: #2E7D32;
    --color-ppt: #E65100;
}

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

html {
    scroll-behavior: smooth;
}

body {
    font-family: var(--font-family);
    background: var(--color-bg);
    color: var(--color-text);
    margin: 0;
    padding: 0;
    min-height: 100vh;
    -webkit-font-smoothing: antialiased;
}

/* ======================== */
/*  Header                  */
/* ======================== */
.site-header {
    position: sticky;
    top: 0;
    z-index: 1000;
    background: var(--color-surface);
    box-shadow: 0 1px 3px var(--color-shadow);
    height: var(--header-height);
}

.header-inner {
    max-width: 960px;
    margin: 0 auto;
    padding: 0 16px;
    height: 100%;
    display: flex;
    align-items: center;
    gap: 12px;
}

.site-logo {
    display: flex;
    align-items: center;
    gap: 6px;
    text-decoration: none;
    color: var(--color-primary);
    font-weight: 700;
    font-size: 1.25rem;
    flex-shrink: 0;
}

.site-logo i {
    font-size: 1.5rem;
}

/* Search */
.search-wrapper {
    flex: 1;
    max-width: 400px;
    position: relative;
}

.search-container {
    position: relative;
    display: flex;
    align-items: center;
}

.search-icon {
    position: absolute;
    left: 12px;
    color: var(--color-text-secondary);
    pointer-events: none;
    font-size: 0.875rem;
}

.search-input {
    width: 100%;
    border: none;
    background: var(--color-bg);
    border-radius: var(--radius-input);
    padding: 8px 36px 8px 36px;
    font-size: 0.9375rem;
    font-family: var(--font-family);
    color: var(--color-text);
    outline: none;
    transition: box-shadow var(--transition-fast);
}

.search-input:focus {
    box-shadow: 0 0 0 2px var(--color-primary);
}

.search-input::placeholder {
    color: var(--color-text-secondary);
}

.search-clear {
    position: absolute;
    right: 8px;
    background: none;
    border: none;
    cursor: pointer;
    color: var(--color-text-secondary);
    padding: 4px;
    display: flex;
    align-items: center;
    font-size: 0.75rem;
}

.search-toggle {
    background: none;
    border: none;
    cursor: pointer;
    color: var(--color-text-secondary);
    font-size: 1.25rem;
    padding: 8px;
}

/* Autocomplete */
.autocomplete-dropdown {
    position: absolute;
    top: 100%;
    left: 0;
    right: 0;
    background: var(--color-surface);
    border-radius: 8px;
    box-shadow: 0 4px 12px rgba(0,0,0,0.15);
    margin-top: 4px;
    overflow: hidden;
    z-index: 100;
}

.autocomplete-item {
    padding: 10px 16px;
    cursor: pointer;
    font-size: 0.9375rem;
    transition: background var(--transition-fast);
}

.autocomplete-item:hover,
.autocomplete-item.active {
    background: var(--color-bg);
}

/* Mobile: search hidden by default */
@media (max-width: 767.98px) {
    .search-wrapper {
        display: none;
        position: absolute;
        top: 0;
        left: 0;
        right: 0;
        height: var(--header-height);
        max-width: none;
        background: var(--color-surface);
        padding: 10px 16px;
        z-index: 10;
    }

    .search-wrapper.open {
        display: flex;
        align-items: center;
    }

    .search-wrapper.open .search-container {
        flex: 1;
    }
}

@media (min-width: 768px) {
    .search-toggle {
        display: none !important;
    }
}

/* ======================== */
/*  Filters Bar             */
/* ======================== */
.filters-bar {
    position: sticky;
    top: var(--header-height);
    z-index: 999;
    background: var(--color-surface);
    border-bottom: 1px solid var(--color-border);
}

.filters-inner {
    max-width: 960px;
    margin: 0 auto;
    padding: 8px 16px;
    display: flex;
    gap: 8px;
    overflow-x: auto;
    scrollbar-width: none;
}

.filters-inner::-webkit-scrollbar {
    display: none;
}

/* ======================== */
/*  Feed Container          */
/* ======================== */
.feed-container {
    max-width: var(--feed-max-width);
    margin: 16px auto;
    padding: 0 16px;
    display: flex;
    flex-direction: column;
    gap: 16px;
}

.feed-sentinel {
    height: 1px;
}

.feed-status {
    text-align: center;
    padding: 24px 16px;
    max-width: var(--feed-max-width);
    margin: 0 auto;
}

.feed-status-text {
    color: var(--color-text-secondary);
    font-size: 0.9375rem;
    margin: 0 0 12px;
}

/* ======================== */
/*  Responsive              */
/* ======================== */
@media (max-width: 575.98px) {
    .feed-container {
        padding: 0 8px;
        gap: 12px;
        margin: 12px auto;
    }
}