@import url('https://fonts.googleapis.com/css2?family=Poppins:wght@400;500;600;700&display=swap');

:root {
    --primary-color: #0d6efd;
    --light-gray: #f8f9fa;
    --dark-gray: #343a40;
    --text-color: #212529;
    --body-bg: #f0f2f5;
}

body {
    font-family: 'Poppins', sans-serif;
    background-color: var(--body-bg);
    color: var(--text-color);
    /* Add padding at the bottom to prevent content from being hidden by the bottom nav */
    padding-bottom: 80px; 
}

.top-header {
    background: white;
    padding: 0.75rem 1rem;
    box-shadow: 0 2px 4px rgba(0,0,0,0.05);
    display: flex;
    justify-content: space-between;
    align-items: center;
    position: sticky;
    top: 0;
    z-index: 1030;
}

.logo {
    font-weight: 700;
    font-size: 1.25rem;
    color: var(--dark-gray);
}

.card {
    border: none;
    border-radius: 1rem;
    box-shadow: 0 8px 25px rgba(0,0,0,0.07);
    margin-bottom: 1.5rem;
}

.form-card .card-body {
    padding: 2rem;
}

.class-list-card .list-group-item {
    padding: 1rem 1.25rem;
    border-bottom: 1px solid #eee !important;
}
.class-list-card .list-group-item:last-child {
    border-bottom: none !important;
}

.lesson-list-item {
    font-size: 1.1rem;
    font-weight: 500;
}
.lesson-list-item i {
    color: var(--primary-color);
    font-size: 1.5rem;
}

/* --- Sticky Bottom Navigation --- */
.bottom-nav {
    position: fixed;
    bottom: 0;
    left: 0;
    right: 0;
    background: white;
    box-shadow: 0 -4px 15px rgba(0,0,0,0.08);
    display: flex;
    justify-content: space-around;
    padding: 0.5rem 0;
    border-top: 1px solid #e9ecef;
    z-index: 1020;
}
.bottom-nav .nav-link {
    display: flex;
    flex-direction: column;
    align-items: center;
    color: #6c757d;
    font-size: 0.75rem;
    font-weight: 500;
}
.bottom-nav .nav-link i {
    font-size: 1.5rem;
    margin-bottom: 2px;
}
.bottom-nav .nav-link.active {
    color: var(--primary-color);
}


/* --- Custom Audio Player --- */
.audio-player {
    display: flex;
    align-items: center;
    gap: 15px;
    background-color: var(--light-gray);
    padding: 1rem;
    border-radius: 0.75rem;
}
.audio-controls button {
    background-color: var(--primary-color);
    color: white;
    width: 50px;
    height: 50px;
    border: none;
    border-radius: 50%;
    font-size: 1.75rem;
    display: flex;
    align-items: center;
    justify-content: center;
}
.time-display {
    font-size: 1.75rem;
    font-weight: 600;
    color: var(--dark-gray);
}