/* HND Study Hub — Premium Theme (Apple/Google inspired) */
:root {
    --premium-blue: #0A73FF;
    --premium-blue-dark: #0556C7;
    --premium-blue-soft: #EAF3FF;
    --premium-blue-glow: rgba(10, 115, 255, 0.18);
    --premium-ink: #111827;
    --premium-muted: #667085;
    --premium-border: #E7ECF3;
    --premium-bg: #F7FAFF;
    --premium-card: #FFFFFF;
    --premium-radius: 22px;
    --premium-radius-lg: 28px;
    --premium-shadow: 0 14px 40px rgba(17, 24, 39, 0.06);
    --premium-shadow-hover: 0 24px 56px rgba(10, 115, 255, 0.14);
    --header-height: 72px;
    --sh-primary: var(--premium-blue);
    --sh-primary-hover: var(--premium-blue-dark);
    --sh-dark: var(--premium-ink);
    --sh-gray: var(--premium-muted);
    --sh-light: var(--premium-bg);
    --sh-glass: rgba(255, 255, 255, 0.88);
    --apple-blue: var(--premium-blue);
    --apple-bg: #fbfcfe;
    --apple-card: #ffffff;
    --apple-text: #1d1d1f;
    --apple-muted: #86868b;
    --card-radius: var(--premium-radius-lg);
    --google-shadow: var(--premium-shadow);
}

.premium-body {
    padding-top: var(--header-height);
    min-height: 100vh;
    background: linear-gradient(180deg, #fff 0%, var(--premium-bg) 45%, #fff 100%) fixed;
}

.premium-main {
    min-height: calc(100vh - var(--header-height) - 80px);
}

/* Header */
#sh-header-wrapper .sh-navbar {
    background: var(--sh-glass);
    backdrop-filter: blur(22px) saturate(180%);
    -webkit-backdrop-filter: blur(22px) saturate(180%);
    border-bottom: 1px solid var(--premium-border);
    height: var(--header-height);
    box-shadow: 0 8px 32px rgba(17, 24, 39, 0.04);
}

.sh-brand { display: flex; align-items: center; gap: 12px; text-decoration: none; }
.sh-brand-icon {
    width: 40px; height: 40px;
    background: linear-gradient(135deg, var(--premium-blue), #56A2FF);
    color: #fff; border-radius: 14px;
    display: flex; align-items: center; justify-content: center;
    font-size: 1.1rem;
    box-shadow: 0 10px 24px var(--premium-blue-glow);
}
.sh-brand-text h1 {
    font-size: 1.08rem; font-weight: 850; color: var(--premium-ink);
    margin: 0; line-height: 1.1; letter-spacing: -0.04em;
}
.sh-brand-text h1 .brand-dot { color: var(--premium-blue); }
.sh-brand-text span {
    font-size: 0.62rem; color: var(--premium-muted); font-weight: 700;
    text-transform: uppercase; letter-spacing: 0.14em;
}

.sh-nav-list { display: flex; align-items: center; gap: 4px; list-style: none; margin: 0; padding: 0; }
.sh-nav-link {
    font-size: 0.86rem; font-weight: 680; color: var(--premium-ink);
    padding: 8px 12px; border-radius: 999px; text-decoration: none;
    transition: 0.2s ease; display: inline-flex; align-items: center; gap: 6px;
}
.sh-nav-link:hover, .sh-nav-link.active { color: var(--premium-blue); background: var(--premium-blue-soft); }

.sh-premium-dropdown {
    border: 1px solid var(--premium-border) !important;
    border-radius: 20px !important;
    padding: 10px !important;
    box-shadow: var(--premium-shadow-hover) !important;
    min-width: 270px;
}
.sh-premium-dropdown .dropdown-item {
    border-radius: 14px; padding: 10px 12px; display: flex; align-items: center; gap: 12px;
}
.sh-premium-dropdown .dropdown-item strong { display: block; font-size: 0.92rem; }
.sh-premium-dropdown .dropdown-item small { color: var(--premium-muted); font-size: 0.72rem; }
.dd-icon {
    width: 40px; height: 40px; border-radius: 12px;
    display: flex; align-items: center; justify-content: center; flex-shrink: 0;
}
.dd-blue { background: var(--premium-blue-soft); color: var(--premium-blue); }
.dd-green { background: #ecfdf5; color: #059669; }
.dd-gray { background: #f3f4f6; color: #6b7280; }

.sh-search-btn {
    width: 40px; height: 40px; border-radius: 14px; border: 1px solid var(--premium-border);
    background: #fff; color: var(--premium-ink); display: flex; align-items: center; justify-content: center;
    text-decoration: none; transition: 0.2s;
}
.sh-search-btn:hover { background: var(--premium-blue-soft); color: var(--premium-blue); }

.sh-btn-login {
    color: var(--premium-ink); font-weight: 700; text-decoration: none;
    padding: 9px 18px; border-radius: 999px; transition: 0.2s;
}
.sh-btn-login:hover { background: #f1f5f9; color: var(--premium-blue); }
.sh-btn-join, .btn-premium {
    background: linear-gradient(135deg, var(--premium-blue), #48A1FF);
    color: #fff !important; padding: 9px 22px; border-radius: 999px;
    font-weight: 700; text-decoration: none;
    box-shadow: 0 12px 28px var(--premium-blue-glow); transition: 0.25s ease; border: 0;
}
.sh-btn-join:hover, .btn-premium:hover { transform: translateY(-2px); color: #fff !important; }

.sh-badge-hot {
    background: #ef4444; color: #fff; font-size: 0.58rem; font-weight: 800;
    padding: 2px 7px; border-radius: 999px; margin-left: 4px;
}

.sh-dropdown { position: relative; }
.sh-dropdown-menu {
    display: none; position: absolute; top: calc(100% + 8px); right: 0;
    background: #fff; border-radius: 18px; padding: 10px;
    box-shadow: var(--premium-shadow-hover); border: 1px solid var(--premium-border);
    min-width: 210px; z-index: 1050;
}
.sh-dropdown:hover .sh-dropdown-menu { display: block; }
.sh-drop-item {
    display: flex; align-items: center; gap: 10px; padding: 10px 12px;
    text-decoration: none; color: var(--premium-ink); font-size: 0.88rem;
    font-weight: 600; border-radius: 12px;
}
.sh-drop-item:hover { background: var(--premium-blue-soft); color: var(--premium-blue); }
.sh-user-profile {
    display: flex; align-items: center; gap: 8px; cursor: pointer;
    padding: 5px 12px 5px 5px; border-radius: 999px;
    background: #fff; border: 1px solid var(--premium-border);
}
.sh-avatar { width: 34px; height: 34px; border-radius: 50%; object-fit: cover; }

.sh-mobile-toggle {
    display: none; background: var(--premium-blue-soft); border: 0;
    color: var(--premium-blue); width: 42px; height: 42px; border-radius: 14px;
    align-items: center; justify-content: center; font-size: 1.1rem;
}
.sh-mobile-drawer { border-left: none !important; box-shadow: -12px 0 40px rgba(0,0,0,0.08) !important; }
.sh-mobile-user {
    display: flex; align-items: center; gap: 12px; padding: 14px;
    background: var(--premium-blue-soft); border-radius: 18px;
}
.sh-mobile-user img { width: 46px; height: 46px; border-radius: 50%; object-fit: cover; }
.sh-mobile-links { display: flex; flex-direction: column; gap: 4px; }
.sh-mobile-links .sh-nav-link { display: flex; align-items: center; gap: 12px; padding: 12px 14px; }

@media (max-width: 991px) {
    .sh-nav-list, .sh-auth-buttons { display: none !important; }
    .sh-mobile-toggle { display: flex; }
}

/* Hero & sections — body already offsets the fixed header */
.hero-section, .library-hero, .notice-hero, .search-hero {
    padding: 28px 0 32px;
    text-align: center;
    position: relative;
}
.hero-section {
    background: radial-gradient(circle at 50% -10%, #fff 0%, var(--premium-bg) 75%);
}
.hero-badge {
    display: inline-flex; align-items: center; gap: 8px;
    background: var(--premium-blue-soft); color: var(--premium-blue);
    border: 1px solid rgba(10, 115, 255, 0.15);
    padding: 7px 18px; border-radius: 999px;
    font-size: 0.74rem; font-weight: 800; letter-spacing: 0.06em;
    text-transform: uppercase; margin-bottom: 22px;
}
.hero-title {
    font-size: clamp(2.2rem, 5.5vw, 3.6rem);
    font-weight: 900; letter-spacing: -0.05em; line-height: 1.08;
    color: var(--premium-ink); margin-bottom: 16px;
}
.hero-subtitle {
    font-size: 1.05rem; color: var(--premium-muted);
    max-width: 640px; margin: 0 auto 32px; line-height: 1.7;
}
.hero-cta-row { display: flex; flex-wrap: wrap; gap: 12px; justify-content: center; }
.btn-ghost {
    background: #fff; color: var(--premium-ink); border: 1px solid var(--premium-border);
    padding: 12px 24px; border-radius: 999px; font-weight: 700; text-decoration: none;
    transition: 0.2s;
}
.btn-ghost:hover { border-color: var(--premium-blue); color: var(--premium-blue); }

.apple-hero-search, .premium-search-bar {
    max-width: 620px; margin: 0 auto 28px;
    background: rgba(255,255,255,0.95);
    border: 1px solid var(--premium-border);
    border-radius: 999px;
    box-shadow: var(--premium-shadow);
    display: flex; align-items: center; padding: 6px 6px 6px 18px;
    transition: 0.25s;
}
.apple-hero-search:focus-within, .premium-search-bar:focus-within {
    border-color: rgba(10,115,255,0.35);
    box-shadow: var(--premium-shadow-hover);
}
.apple-hero-search input, .premium-search-bar input {
    border: 0; background: transparent; flex: 1; outline: 0;
    font-size: 0.95rem; padding: 10px 8px;
}
.apple-hero-search button, .premium-search-bar button {
    border: 0; background: linear-gradient(135deg, var(--premium-blue), #48A1FF);
    color: #fff; border-radius: 999px; padding: 10px 20px; font-weight: 750;
}

/* Cards */
.section-title {
    text-align: center; font-size: clamp(1.6rem, 3vw, 2.3rem);
    font-weight: 850; letter-spacing: -0.04em; margin-bottom: 36px;
}
.topic-grid {
    display: grid;
    grid-template-columns: repeat(4, minmax(0, 1fr));
    gap: 20px;
}
.topic-card {
    background: var(--premium-card);
    border: 1px solid var(--premium-border);
    border-radius: var(--premium-radius-lg);
    overflow: hidden;
    text-decoration: none; color: inherit;
    box-shadow: var(--premium-shadow);
    transition: 0.3s cubic-bezier(0.2, 0.8, 0.2, 1);
}
.topic-card:hover {
    transform: translateY(-6px);
    box-shadow: var(--premium-shadow-hover);
    border-color: rgba(10,115,255,0.25);
    color: inherit;
}
.topic-card-img {
    height: 150px; background: linear-gradient(135deg, var(--premium-blue-soft), #fff);
    display: flex; align-items: center; justify-content: center;
    font-size: 2.8rem; color: var(--premium-blue);
}
.topic-card-body { padding: 18px 20px 22px; }
.topic-card-body h3 { font-size: 1.05rem; font-weight: 800; margin: 0 0 4px; }
.topic-card-body p { margin: 0; font-size: 0.82rem; color: var(--premium-muted); font-weight: 600; }

.articles-split {
    display: grid; grid-template-columns: 1fr 1.2fr; gap: 40px; align-items: start;
}
.article-list-item {
    display: block; padding: 18px 0;
    border-bottom: 1px solid var(--premium-border);
    text-decoration: none; color: inherit;
    transition: 0.2s;
}
.article-list-item:hover { color: var(--premium-blue); padding-left: 6px; }
.article-list-item h4 { font-size: 1rem; font-weight: 780; margin: 0 0 6px; }
.article-list-item .meta { font-size: 0.78rem; color: var(--premium-muted); }
.article-tag {
    display: inline-block; margin-top: 8px;
    background: var(--premium-blue-soft); color: var(--premium-blue);
    font-size: 0.7rem; font-weight: 800; padding: 4px 10px; border-radius: 999px;
}

/* Library wizard */
.library-shell {
    max-width: 900px; margin: -40px auto 40px; padding: 0 16px; position: relative; z-index: 5;
}
.wizard-card {
    background: #fff; border: 1px solid var(--premium-border);
    border-radius: var(--premium-radius-lg); box-shadow: var(--premium-shadow-hover);
    padding: 28px;
}
.wizard-steps { display: flex; flex-wrap: wrap; gap: 8px; margin-bottom: 20px; }
.wizard-step-pill {
    padding: 8px 14px; border-radius: 999px; font-size: 0.78rem; font-weight: 750;
    background: #f3f4f6; color: var(--premium-muted);
}
.wizard-step-pill.active { background: var(--premium-blue-soft); color: var(--premium-blue); }
.wizard-step-pill.done { background: #ecfdf5; color: #059669; }
.filter-toolbar {
    display: flex; flex-wrap: wrap; gap: 10px; margin-bottom: 18px;
}
.filter-chip {
    border: 1px solid var(--premium-border); background: #fff;
    border-radius: 999px; padding: 8px 14px; font-size: 0.8rem; font-weight: 700;
    cursor: pointer; transition: 0.2s;
}
.filter-chip:hover, .filter-chip.active {
    background: var(--premium-blue-soft); border-color: rgba(10,115,255,0.3); color: var(--premium-blue);
}
.option-grid { display: grid; grid-template-columns: repeat(auto-fill, minmax(140px, 1fr)); gap: 10px; }
.option-btn {
    border: 1px solid var(--premium-border); background: #fff; border-radius: 16px;
    padding: 14px 12px; text-align: center; font-weight: 700; font-size: 0.86rem;
    cursor: pointer; transition: 0.2s;
}
.option-btn:hover, .option-btn.selected {
    border-color: var(--premium-blue); background: var(--premium-blue-soft); color: var(--premium-blue);
}

/* Notices */
.notice-hero { background: radial-gradient(circle at top, #fff, var(--premium-bg)); }
.notice-filters {
    display: flex; flex-wrap: wrap; gap: 10px; justify-content: center; margin-bottom: 28px;
}
.notice-card-premium {
    background: #fff; border: 1px solid var(--premium-border);
    border-radius: var(--premium-radius); overflow: hidden;
    box-shadow: var(--premium-shadow); transition: 0.3s;
    height: 100%; display: flex; flex-direction: column;
}
.notice-card-premium:hover { transform: translateY(-4px); box-shadow: var(--premium-shadow-hover); }
.notice-card-premium .nc-img { height: 180px; object-fit: cover; width: 100%; background: var(--premium-blue-soft); }
.notice-card-premium .nc-body { padding: 20px; flex: 1; display: flex; flex-direction: column; }
.priority-pill {
    font-size: 0.68rem; font-weight: 800; text-transform: uppercase;
    padding: 4px 10px; border-radius: 999px; display: inline-block;
}
.priority-urgent { background: #fee2e2; color: #b91c1c; }
.priority-high { background: #ffedd5; color: #c2410c; }
.priority-medium { background: var(--premium-blue-soft); color: var(--premium-blue); }
.priority-low { background: #f3f4f6; color: #6b7280; }
.pin-badge { color: #f59e0b; margin-right: 4px; }

.scroll-hint {
    width: 42px; height: 42px; border-radius: 50%;
    border: 1px solid var(--premium-border); color: var(--premium-muted);
    display: flex; align-items: center; justify-content: center;
    margin: 20px auto 0; animation: bounceY 2s infinite;
}
@keyframes bounceY {
    0%, 100% { transform: translateY(0); }
    50% { transform: translateY(6px); }
}

@media (max-width: 991px) {
    .topic-grid { grid-template-columns: repeat(2, minmax(0, 1fr)); }
    .articles-split { grid-template-columns: 1fr; }
    .hero-section, .library-hero, .notice-hero, .search-hero {
        padding: 16px 0 20px;
    }
    .hero-subtitle { margin-bottom: 18px; }
    .apple-hero-search, .premium-search-bar { margin-bottom: 16px; }
    .scroll-hint { display: none; }
}
@media (max-width: 576px) {
    .topic-grid { grid-template-columns: 1fr; }
    .hero-section, .library-hero, .notice-hero, .search-hero {
        padding: 12px 0 16px;
    }
}