/* ====================================================
   NEB Archive — Grade 12 Science Subjects Page Styles
   ==================================================== */

/* ---------- Design System / Variables ---------- */
:root {
    --bg: #FAFAFA;
    --bg-alt: #FFFFFF;
    --text: #1A1A1A;
    --text-muted: #6B7280;
    --accent: #4F46E5;
    --accent-hover: #4338CA;
    --accent-light: #EEF2FF;
    --border: #E5E7EB;
    --navbar-bg: rgba(250, 250, 250, 0.85);
    --card-shadow: 0 1px 3px rgba(0, 0, 0, 0.06), 0 1px 2px rgba(0, 0, 0, 0.04);
    --card-shadow-hover: 0 12px 28px rgba(0, 0, 0, 0.08), 0 4px 10px rgba(0, 0, 0, 0.04);
    --font: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
    --container: 1140px;
    --radius: 12px;
    --radius-sm: 8px;
    --transition: 0.25s cubic-bezier(0.4, 0, 0.2, 1);
}

[data-theme="dark"] {
    --bg: #0F172A;
    --bg-alt: #1E293B;
    --text: #F1F5F9;
    --text-muted: #94A3B8;
    --accent: #818CF8;
    --accent-hover: #6366F1;
    --accent-light: #312E81;
    --border: #334155;
    --navbar-bg: rgba(15, 23, 42, 0.85);
    --card-shadow: 0 1px 3px rgba(0, 0, 0, 0.4), 0 1px 2px rgba(0, 0, 0, 0.2);
    --card-shadow-hover: 0 12px 28px rgba(0, 0, 0, 0.5), 0 4px 10px rgba(0, 0, 0, 0.3);
}

/* ---------- Reset ---------- */
* { margin: 0; padding: 0; box-sizing: border-box; }
body {
    font-family: var(--font);
    background: var(--bg);
    color: var(--text);
    line-height: 1.6;
    transition: background 0.3s ease, color 0.3s ease;
}
a { text-decoration: none; color: inherit; }
.container { width: 100%; max-width: var(--container); margin: 0 auto; padding: 0 24px; }

/* ---------- Buttons ---------- */
.btn { display: inline-flex; align-items: center; justify-content: center; gap: 8px; padding: 12px 24px; font-family: inherit; font-size: 15px; font-weight: 600; border-radius: var(--radius-sm); border: 2px solid transparent; cursor: pointer; transition: all var(--transition); }
.btn-primary { background: var(--accent); color: #fff; }
.btn-sm { padding: 8px 18px; font-size: 14px; }

/* ====================================================
   NAVBAR
   ==================================================== */
.navbar { position: sticky; top: 0; z-index: 1000; background: var(--navbar-bg); backdrop-filter: saturate(180%) blur(12px); -webkit-backdrop-filter: saturate(180%) blur(12px); border-bottom: 1px solid var(--border); }
.nav-container { max-width: var(--container); margin: 0 auto; padding: 0 24px; height: 68px; display: flex; align-items: center; justify-content: space-between; }
.logo { font-size: 20px; font-weight: 700; color: var(--text); display: flex; align-items: center; gap: 8px; }
.logo-mark { color: var(--accent); }
.logo-accent { color: var(--accent); }
.nav-links { display: flex; align-items: center; gap: 32px; }
.nav-link { font-size: 15px; font-weight: 500; color: var(--text-muted); transition: color var(--transition); position: relative; }
.nav-link:hover, .nav-link.active { color: var(--text); }
.nav-link.active::after { content: ''; position: absolute; bottom: -6px; left: 0; right: 0; height: 2px; background: var(--accent); border-radius: 2px; }
.hamburger { display: none; flex-direction: column; justify-content: space-between; width: 26px; height: 20px; background: transparent; border: none; cursor: pointer; padding: 0; }
.hamburger span { display: block; height: 2.5px; width: 100%; background: var(--text); border-radius: 2px; transition: all var(--transition); }
.hamburger.active span:nth-child(1) { transform: translateY(8.5px) rotate(45deg); }
.hamburger.active span:nth-child(2) { opacity: 0; }
.hamburger.active span:nth-child(3) { transform: translateY(-8.5px) rotate(-45deg); }
.theme-toggle { display: flex; align-items: center; justify-content: center; width: 40px; height: 40px; background: transparent; border: 1px solid var(--border); border-radius: var(--radius-sm); cursor: pointer; color: var(--text-muted); transition: all var(--transition); }
.theme-toggle:hover { color: var(--accent); border-color: var(--accent); background: var(--accent-light); }
.theme-toggle svg { width: 20px; height: 20px; }
.icon-sun { display: block; } .icon-moon { display: none; }
[data-theme="dark"] .icon-sun { display: none; } [data-theme="dark"] .icon-moon { display: block; }

/* ====================================================
   PAGE HEADER
   ==================================================== */
.page-header { padding: 64px 0 32px; text-align: center; background: linear-gradient(180deg, var(--bg) 0%, var(--accent-light) 100%); }
.badge { display: inline-block; background: var(--bg-alt); color: var(--accent); font-size: 13px; font-weight: 600; padding: 6px 14px; border-radius: 50px; border: 1px solid var(--border); margin-bottom: 20px; }
.back-link { 
    display: block; 
    text-align: left; 
    margin-bottom: 32px; 
    font-size: 14px; 
    font-weight: 600; 
    color: var(--text-muted); 
    transition: color var(--transition); 
}
.back-link:hover { color: var(--accent); }
.page-title { font-size: clamp(2rem, 4.5vw, 3rem); font-weight: 800; line-height: 1.1; letter-spacing: -1.5px; margin-bottom: 16px; }
.page-subtitle { font-size: 1.1rem; color: var(--text-muted); max-width: 560px; margin: 0 auto; }

/* ====================================================
   RESULTS GRID & CARDS
   ==================================================== */
.pyq-results-section { padding: 64px 0; }

.pyq-grid {
    display: flex;
    flex-wrap: wrap;
    justify-content: center;
    gap: 24px;
}

.pyq-card {
    background: var(--bg-alt);
    border: 1px solid var(--border);
    border-radius: var(--radius);
    padding: 28px 24px;
    display: flex;
    flex-direction: column;
    transition: all var(--transition);
    flex: 1 1 300px;
    max-width: 350px;
    box-sizing: border-box;
}
.pyq-card:hover { transform: translateY(-6px); box-shadow: var(--card-shadow-hover); border-color: transparent; }
.card-meta-top { display: flex; justify-content: space-between; align-items: center; margin-bottom: 16px; }

.tag { font-size: 12px; font-weight: 600; padding: 4px 10px; border-radius: 50px; text-transform: uppercase; letter-spacing: 0.5px; }
.tag.science { background: #ECFDF5; color: #059669; }
[data-theme="dark"] .tag.science { background: #064E3B; color: #34D399; }

.notes-icon { font-size: 28px; width: 52px; height: 52px; display: flex; align-items: center; justify-content: center; background: var(--accent-light); border-radius: 12px; margin-bottom: 20px; }
.pyq-card h3 { font-size: 1.3rem; font-weight: 700; margin-bottom: 8px; color: var(--text); }
.pyq-card p { font-size: 14px; color: var(--text-muted); margin-bottom: 18px; flex-grow: 1; }
.card-link { font-size: 14px; font-weight: 600; color: var(--accent); transition: gap var(--transition); display: inline-block; margin-top: auto; }

/* ====================================================
   FOOTER
   ==================================================== */
.footer { background: var(--bg); border-top: 1px solid var(--border); padding: 48px 0 24px; }
.footer-content { display: flex; justify-content: space-between; align-items: center; flex-wrap: wrap; gap: 24px; padding-bottom: 32px; border-bottom: 1px solid var(--border); }
.footer-tagline { color: var(--text-muted); font-size: 14px; margin-top: 8px; }
.footer-links { display: flex; gap: 28px; }
.footer-links a { color: var(--text-muted); font-size: 14px; font-weight: 500; transition: color var(--transition); }
.footer-links a:hover { color: var(--accent); }
.footer-bottom { text-align: center; padding-top: 24px; color: var(--text-muted); font-size: 13.5px; }

/* ====================================================
   RESPONSIVE
   ==================================================== */
@media (max-width: 640px) {
    .nav-links { position: fixed; top: 68px; left: 0; right: 0; flex-direction: column; background: var(--bg-alt); padding: 24px; gap: 8px; border-bottom: 1px solid var(--border); box-shadow: 0 10px 20px rgba(0, 0, 0, 0.06); transform: translateY(-120%); opacity: 0; visibility: hidden; transition: all 0.35s ease; align-items: stretch; }
    .nav-links.open { transform: translateY(0); opacity: 1; visibility: visible; }
    .nav-link { padding: 12px 8px; font-size: 16px; border-radius: var(--radius-sm); }
    .nav-link.active::after { display: none; }
    .nav-link.active { background: var(--accent-light); color: var(--accent); }
    .nav-cta { margin-top: 8px; text-align: center; }
    .hamburger { display: flex; }
    .footer-content { flex-direction: column; text-align: center; }
}