:root {
    --bg-page: #f4f7fb;
    --bg-card: #ffffff;
    --accent-blue: #3b5bfd;
    --accent-blue-dark: #2a46e0;
    --accent-green: #16a34a;
    --text-dark: #1a2233;
    --text-muted: #6b7684;
    --border-light: #e6eaf0;
}

* { box-sizing: border-box; margin: 0; padding: 0; }

body {
    background: linear-gradient(180deg, #eef2ff 0%, #f4f7fb 40%, #eefcf5 100%);
    color: var(--text-dark);
    font-family: 'Segoe UI', sans-serif;
}

header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 14px 26px;
    background: #ffffff;
    border-radius: 40px;
    margin: 16px 20px;
    box-shadow: 0 6px 20px rgba(20,30,60,0.08);
}

.site-logo { height: 30px; width: auto; display: block; }

.menu-icon {
    font-size: 24px;
    cursor: pointer;
    color: var(--text-dark);
    background: #f0f3fa;
    border: none;
    width: 42px;
    height: 42px;
    border-radius: 50%;
}

.side-menu {
    position: fixed;
    top: 0; right: -280px;
    width: 260px; height: 100%;
    background: #ffffff;
    transition: right 0.3s ease;
    padding: 60px 20px;
    z-index: 999;
    box-shadow: -8px 0 30px rgba(20,30,60,0.15);
}

.side-menu.open { right: 0; }

.side-menu a {
    display: block;
    color: var(--text-dark);
    text-decoration: none;
    padding: 12px 0;
    border-bottom: 1px solid var(--border-light);
    font-weight: 600;
    transition: color 0.2s, padding-left 0.2s;
}

.side-menu a:hover { color: var(--accent-blue); padding-left: 6px; }

.close-btn {
    position: absolute; top: 15px; right: 20px;
    font-size: 26px; cursor: pointer; color: var(--text-dark);
}

.hero { text-align: center; padding: 50px 20px 40px; animation: fadeSlideUp 0.6s ease-out; }

.hero-badges { display: flex; justify-content: center; flex-wrap: wrap; gap: 10px; margin-bottom: 25px; }

.badge {
    background: #ffffff;
    border-radius: 30px;
    padding: 8px 18px;
    font-size: 13px;
    font-weight: 600;
    color: var(--text-dark);
    box-shadow: 0 4px 14px rgba(20,30,60,0.06);
    display: flex;
    align-items: center;
    gap: 8px;
}

.badge .dot { width: 8px; height: 8px; border-radius: 50%; background: var(--accent-green); }
.badge.blue .dot { background: var(--accent-blue); }
.badge.purple .dot { background: #9333ea; }

.hero h1 { font-size: 34px; font-weight: 800; line-height: 1.3; margin-bottom: 14px; color: var(--text-dark); }

.hero h1 .highlight {
    background: linear-gradient(90deg, var(--accent-blue), #7c3aed);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
}

.hero p { max-width: 600px; margin: 0 auto 28px; color: var(--text-muted); line-height: 1.7; font-size: 15px; }

.hero-cta {
    display: inline-flex;
    align-items: center;
    gap: 10px;
    background: linear-gradient(135deg, var(--accent-blue), #5b3df0);
    color: #fff;
    padding: 15px 32px;
    border-radius: 30px;
    text-decoration: none;
    font-weight: 700;
    font-size: 15px;
    box-shadow: 0 10px 25px rgba(59,91,253,0.35);
    transition: transform 0.15s, box-shadow 0.15s;
}

.hero-cta:hover { transform: translateY(-3px); box-shadow: 0 14px 30px rgba(59,91,253,0.45); }

.filter-bar { display: flex; gap: 10px; flex-wrap: wrap; justify-content: center; padding: 10px 30px 0; }

.filter-btn {
    background: #ffffff;
    color: var(--text-dark);
    border: 1px solid var(--border-light);
    padding: 9px 20px;
    border-radius: 20px;
    cursor: pointer;
    font-size: 14px;
    font-weight: 600;
    text-decoration: none;
    transition: all 0.2s;
    box-shadow: 0 3px 10px rgba(20,30,60,0.05);
}

.filter-btn.active, .filter-btn:hover { background: var(--accent-blue); color: #fff; border-color: var(--accent-blue); }

.course-grid { display: grid; grid-template-columns: repeat(auto-fill, minmax(280px, 1fr)); gap: 25px; padding: 35px 30px; }

.course-card {
    background: var(--bg-card);
    border-radius: 16px;
    overflow: hidden;
    transition: transform 0.25s, box-shadow 0.25s;
    border: 1px solid var(--border-light);
    box-shadow: 0 6px 18px rgba(20,30,60,0.06);
    animation: fadeSlideUp 0.5s ease-out;
    animation-fill-mode: both;
}

.course-card:hover { transform: translateY(-6px); box-shadow: 0 16px 30px rgba(20,30,60,0.14); }

.course-card img { width: 100%; height: 170px; object-fit: cover; }

.course-card-body { padding: 18px; }

.course-card h3 { color: var(--text-dark); margin-bottom: 5px; font-size: 18px; }

.course-card .instructor { color: var(--text-muted); font-size: 13px; margin-bottom: 8px; }

.course-card .desc { color: var(--text-muted); font-size: 13px; line-height: 1.5; margin-bottom: 10px; }

.course-card .price { color: var(--accent-blue); font-weight: 800; font-size: 17px; margin-top: 5px; }

.btn {
    display: inline-block;
    background: linear-gradient(135deg, var(--accent-blue), #5b3df0);
    color: #fff;
    padding: 10px 22px;
    border-radius: 20px;
    text-decoration: none;
    font-weight: 700;
    border: none;
    cursor: pointer;
    margin-top: 10px;
    transition: opacity 0.2s, transform 0.2s;
    box-shadow: 0 6px 16px rgba(59,91,253,0.3);
}

.btn:hover { opacity: 0.92; transform: translateY(-2px); }

.balance-pill {
    display: flex;
    align-items: center;
    gap: 6px;
    background: #eef2ff;
    border: 1px solid #d6ddff;
    color: var(--accent-blue-dark);
    padding: 7px 16px;
    border-radius: 20px;
    font-size: 14px;
    font-weight: 700;
    text-decoration: none;
    transition: transform 0.15s;
}

.balance-pill::before {
    content: '৳';
    display: flex;
    align-items: center;
    justify-content: center;
    width: 20px;
    height: 20px;
    border-radius: 50%;
    background: var(--accent-blue);
    color: #fff;
    font-size: 12px;
    font-weight: 800;
}

.balance-pill:hover { transform: translateY(-2px); }

.auth-wrapper { min-height: 75vh; display: flex; align-items: center; justify-content: center; padding: 40px 20px; }

.auth-card {
    width: 100%;
    max-width: 420px;
    background: #ffffff;
    border-radius: 20px;
    padding: 40px 35px;
    border: 1px solid var(--border-light);
    box-shadow: 0 20px 50px rgba(20,30,60,0.1);
    position: relative;
    overflow: hidden;
    animation: fadeSlideUp 0.6s ease-out;
}

.auth-subtitle { text-align: center; color: var(--text-muted); font-size: 13px; margin-bottom: 28px; }

.input-group { margin-bottom: 16px; animation: fadeSlideUp 0.6s ease-out; animation-fill-mode: both; }

.input-group:nth-child(1) { animation-delay: 0.05s; }
.input-group:nth-child(2) { animation-delay: 0.1s; }
.input-group:nth-child(3) { animation-delay: 0.15s; }
.input-group:nth-child(4) { animation-delay: 0.2s; }

.input-group label {
    display: block;
    font-size: 12px;
    color: var(--text-muted);
    margin-bottom: 6px;
    text-transform: uppercase;
    letter-spacing: 0.5px;
    font-weight: 700;
}

.input-group input, .input-group select {
    width: 100%;
    padding: 13px 14px;
    border-radius: 10px;
    border: 1.5px solid var(--border-light);
    background: #f9fafc;
    color: var(--text-dark);
    font-size: 14px;
    transition: border-color 0.2s, box-shadow 0.2s;
}

.input-group input:focus, .input-group select:focus {
    outline: none;
    border-color: var(--accent-blue);
    box-shadow: 0 0 0 3px rgba(59,91,253,0.15);
}

.input-group input:disabled { opacity: 0.6; }

.check-row { display: flex; align-items: center; gap: 8px; margin: 18px 0; font-size: 13px; color: var(--text-muted); }

.check-row input { width: auto; margin: 0; }

.btn-premium {
    width: 100%;
    padding: 14px;
    border: none;
    border-radius: 12px;
    background: linear-gradient(135deg, var(--accent-blue), #5b3df0);
    color: #fff;
    font-weight: 700;
    font-size: 15px;
    cursor: pointer;
    box-shadow: 0 10px 25px rgba(59,91,253,0.3);
    transition: transform 0.15s, box-shadow 0.15s;
}

.btn-premium:hover { transform: translateY(-2px); box-shadow: 0 14px 30px rgba(59,91,253,0.4); }
.btn-premium:active { transform: scale(0.97); }

.auth-footer { text-align: center; margin-top: 22px; font-size: 13px; color: var(--text-muted); }

.auth-footer a { color: var(--accent-blue); text-decoration: none; font-weight: 700; }

.error-box {
    background: #fef2f2;
    border: 1px solid #fecaca;
    color: #dc2626;
    padding: 10px 14px;
    border-radius: 10px;
    font-size: 13px;
    margin-bottom: 18px;
}

.success-box {
    background: #eef2ff;
    border: 1px solid #c7d2fe;
    color: var(--accent-blue-dark);
    padding: 10px 14px;
    border-radius: 10px;
    font-size: 13px;
    margin-bottom: 18px;
}

.detail-card {
    max-width: 650px;
    margin: 40px auto;
    background: var(--bg-card);
    border-radius: 20px;
    padding: 30px;
    border: 1px solid var(--border-light);
    box-shadow: 0 10px 30px rgba(20,30,60,0.08);
}

.detail-card img { width: 100%; border-radius: 14px; margin-bottom: 15px; }

.site-footer {
    text-align: center;
    padding: 30px 20px;
    color: var(--text-muted);
    font-size: 13px;
    border-top: 1px solid var(--border-light);
    margin-top: 20px;
}

.site-footer p { margin: 4px 0; }

.site-footer a { color: var(--accent-blue); text-decoration: none; font-weight: 700; }

.site-footer a:hover { text-decoration: underline; }

@keyframes fadeSlideUp {
    from { opacity: 0; transform: translateY(25px); }
    to { opacity: 1; transform: translateY(0); }
}