.btn-selected,
.btn {
    display: inline-block;
    width: 120px;
    height: 36px;
    line-height: 36px;
    font-size: 14px;
    font-family: inherit;
    border: none;
    border-radius: 10px;
    background: #64829b;
    color: white;
    cursor: pointer;
    text-decoration: none;
    text-align: center;
    box-sizing: border-box;
    appearance: none;
    -webkit-appearance: none;
    margin: 0;
}

.btn-selected {
    background: linear-gradient(180deg, #c7deec 0%, #a0c4db 100%);
    color: #2a2a2a;
    cursor: default;
    box-shadow: 0 0 3px rgba(0, 0, 0, 0.5);
}

.btn:hover,
.btn:active {
    background: linear-gradient(180deg, #98bcd3 0%, #92b6cc 100%);
    color: #2a2a2a;
}

.btn:focus {
    outline: 2px solid #888;
    outline-offset: 1px;
}

.btn:disabled,
.btn.disabled {
    opacity: 0.5;
    cursor: not-allowed;
}

.btn-primary {
    width: 220px;
}

.btn-primary:hover {
    background: #a0c4db;
}

.btn-danger {
    background: #e8e8e8;
    color: #8a3a39;
    border-color: #b8b8b8;
}

.btn-danger:hover {
    background: #d4d4d4;
    border-color: #8a3a39;
}

.btn-small {
    width: auto;
    height: auto;
    padding: 5px 10px;
    font-size: 13px;
    line-height: 1.3;
    border-radius: 10px;
    background: #64829b;
    color: white;
}

.btn-small:hover {
    background: linear-gradient(180deg, #a0c4db 0%, #a0c4db 100%);
    color: #2a2a2a;
}

.btn-link {
    width: auto;
    height: auto;
    background: transparent;
    border: none;
    color: #555;
    text-decoration: underline;
    padding: 0;
    cursor: pointer;
    font-size: 14px;
    line-height: 1.3;
}

.btn-link:hover {
    color: #222;
    background: transparent;
}

.back::before {
    content: "❮";
    padding-right: 16px;
}

.back-to-top {
    position: fixed;
    bottom: 30px;
    right: 30px;
    width: 48px;
    height: 48px;
    border: none;
    border-radius: 10px;
    background: #64829b;
    color: white;
    cursor: pointer;
    font-size: 28px;
    line-height: 1;
    display: flex;
    align-items: center;
    justify-content: center;
    box-shadow: 0 0 12px rgba(0, 0, 0, 0.25);
    opacity: 0;
    visibility: hidden;
    z-index: 1000;
    -webkit-tap-highlight-color: transparent;
    user-select: none;
    -webkit-user-select: none;
    transform: rotate(0deg);
}

.back-to-top .arrow {
    display: inline-block;
    transform: rotate(90deg);
    line-height: 1;
}

.back-to-top.visible {
    opacity: 1;
    visibility: visible;
}

.back-to-top:hover {
    background: linear-gradient(180deg, #d0dee7 0%, #d2e3ee 100%);
    color: #2a2a2a;
    box-shadow: 0 0 12px rgba(0, 0, 0, 0.55);
}

.back-to-top:active {
    background: linear-gradient(180deg, #98bcd3 0%, #92b6cc 100%);
    color: #2a2a2a;
}

.back-to-top:focus {
    outline: 2px solid #888;
    outline-offset: 1px;
}

@media (pointer: coarse) {
    .back-to-top {
        width: 52px;
        height: 52px;
        font-size: 30px;
        bottom: 20px;
        right: 20px;
    }
}

@media (max-width: 480px) {
    .back-to-top {
        bottom: 20px;
        right: 20px;
    }
}