/* Header */
header {
    background-color: #FFDB4D;
    height: 56px;
    padding: 0;
    text-align: center;
    box-shadow: 0 2px 5px rgba(0,0,0,0.1);
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    z-index: 1000;
    display: flex;
    align-items: center;
    justify-content: center;
    box-sizing: border-box;
}

header h1 {
    font-size: 1.55rem;
    color: #4B3D00;
    padding: 0 50px;
    margin: 0;
    line-height: 56px;
    font-weight: 800;
    white-space: nowrap;
}

/* Menu Button */
.menu-toggle {
    font-size: 19px;
    cursor: pointer;
    position: fixed;
    top: 10px;
    left: 14px;
    height: 36px;
    width: 38px;
    display: flex;
    align-items: center;
    justify-content: center;
    background-color: #FFD466;
    color: #4B3D00;
    border-radius: 8px;
    z-index: 1006;
    box-shadow: 0 2px 6px rgba(0,0,0,0.18);
    user-select: none;
    box-sizing: border-box;
    transition: background 0.2s ease, transform 0.1s ease;
}

.menu-toggle:active {
    background-color: #f7ca50;
    transform: scale(0.96);
}

/* Share Button */
.share-button {
    position: fixed;
    top: 13px;
    right: 14px;
    height: 30px;
    width: 30px;
    display: flex;
    align-items: center;
    justify-content: center;
    z-index: 1006;
    cursor: pointer;
    color: #221f0f;
    box-sizing: border-box;
}

.share-button svg {
    display: block;
    width: 26px;
    height: 26px;
}

/* Sidebar */
.sidebar {
    width: 260px;
    box-sizing: border-box;
    background-color: #fff;
    padding: 15px;
    position: fixed;
    top: 56px;
    left: -290px;
    height: calc(100% - 56px);
    box-shadow: 3px 0 15px rgba(0,0,0,0.18);
    transition: left 0.3s ease;
    z-index: 1005;
    overflow-y: auto;
}

.sidebar.open {
    left: 0;
}

.sidebar ul {
    list-style: none;
    padding: 6px 0;
    margin: 0;
}

.sidebar ul li {
    margin-bottom: 10px;
}

.sidebar a {
    display: block;
    text-decoration: none;
    color: #161201;
    font-size: 16px;
    font-weight: 500;
    padding: 8px 12px;
    border-radius: 6px;
    transition: background 0.2s ease;
}

.sidebar a:hover {
    background-color: #f5f4ef;
}

.subjects {
    display: none;
    margin-left: 15px;
    margin-top: 5px;
}

.subjects li a {
    font-size: 15px;
    color: #333;
}

.subjects li a:hover {
    background-color: #ffe680;
}

/* Mobile */
@media (max-width: 768px) {
    header {
        height: 52px;
    }
    header h1 {
        font-size: 1.35rem;
        line-height: 52px;
    }
    .menu-toggle {
        top: 8px;
        left: 10px;
        height: 36px;
        width: 36px;
        font-size: 18px;
    }
    .share-button {
        top: 12px;
        right: 10px;
    }
    .sidebar {
        width: 240px;
        top: 52px;
        left: -270px;
        height: calc(100% - 52px);
    }
    .sidebar.open {
        left: 0;
    }
}

/* Floating WhatsApp Share Button */
.whatsapp-share {
    position: fixed;
    bottom: 22px;
    right: 22px;
    width: 58px;
    height: 58px;
    border-radius: 50%;
    background: #25D366;
    display: flex;
    align-items: center;
    justify-content: center;
    box-shadow: 0 4px 14px rgba(0, 0, 0, 0.28);
    z-index: 99999;
    cursor: pointer;
    text-decoration: none;
    transition: transform 0.2s ease, box-shadow 0.2s ease, background 0.2s ease;
    -webkit-tap-highlight-color: transparent;
}

.whatsapp-share:hover {
    background: #20ba5a;
    transform: scale(1.06);
    box-shadow: 0 6px 20px rgba(37, 211, 102, 0.45);
}

.whatsapp-share:active {
    transform: scale(0.93);
}

.whatsapp-share svg {
    width: 30px;
    height: 30px;
    fill: #ffffff;
    display: block;
}

@media (max-width: 768px) {
    .whatsapp-share {
        bottom: 18px;
        right: 18px;
        width: 52px;
        height: 52px;
        box-shadow: 0 3px 12px rgba(0, 0, 0, 0.32);
    }
    .whatsapp-share svg {
        width: 27px;
        height: 27px;
    }
}