.guestbook-container {
    max-width: 700px;
    margin: 3rem auto;
    padding: 0 2rem;
}
.guestbook-title {
    font-size: 1.8rem;
    font-weight: 700;
    margin-bottom: 1.5rem;
}
.guestbook-form {
    margin-bottom: 2rem;
}
.guestbook-form textarea {
    width: 100%;
    padding: 0.8rem;
    border: 1px solid var(--color-gray-400);
    border-radius: var(--radius-lg);
    resize: vertical;
    min-height: 80px;
    font-family: inherit;
    font-size: 0.95rem;
    background: var(--color-bg-secondary, #fff);
    color: var(--color-text);
}
.guestbook-form textarea:focus {
    outline: none;
    border-color: var(--color-primary);
}
.guestbook-form-footer {
    display: flex;
    justify-content: flex-end;
    margin-top: 0.5rem;
}
.guestbook-form button {
    background: var(--color-primary);
    color: var(--color-white);
    border: none;
    padding: 0.5rem 1.2rem;
    border-radius: var(--radius-md);
    cursor: pointer;
    font-weight: 500;
}
.guestbook-form button:hover {
    opacity: 0.9;
}
.guestbook-login {
    text-align: center;
    padding: 1.5rem;
    background: var(--color-bg-secondary, #f5f5f5);
    border-radius: var(--radius-lg);
    margin-bottom: 2rem;
}
.guestbook-login a {
    color: var(--color-primary);
    font-weight: 500;
}
.entry-list {
    display: flex;
    flex-direction: column;
    gap: 1rem;
}
.entry-item {
    background: var(--color-bg-secondary, #f9f9f9);
    padding: 1rem;
    border-radius: var(--radius-lg);
    border-left: 3px solid var(--color-primary);
}
.entry-header {
    display: flex;
    justify-content: space-between;
    margin-bottom: 0.5rem;
    font-size: 0.85rem;
}
.entry-author {
    font-weight: 600;
    color: var(--color-primary);
}
.entry-date {
    color: var(--color-gray-600);
}
.entry-content {
    line-height: 1.6;
    white-space: pre-wrap;
}
.no-entries {
    text-align: center;
    color: var(--color-gray-600);
    padding: 2rem;
}

body.dark-mode .guestbook-form textarea {
    background: var(--color-bg-tertiary);
    border-color: var(--color-gray-400);
}
body.dark-mode .entry-item {
    background: var(--color-bg-tertiary);
}
body.dark-mode .guestbook-login {
    background: var(--color-bg-tertiary);
}

/* ===== Responsive: 768px (Small Tablet) ===== */
@media (max-width: 768px) {
    .guestbook-container {
        margin: 2rem auto;
        padding: 0 1.5rem;
    }

    .guestbook-title {
        font-size: 1.5rem;
    }
}

/* ===== Responsive: 600px (Large Phone) ===== */
@media (max-width: 600px) {
    .guestbook-container {
        margin: 1.5rem auto;
        padding: 0 1rem;
    }

    .guestbook-title {
        font-size: 1.3rem;
        margin-bottom: 1rem;
    }

    .guestbook-form textarea {
        padding: 0.7rem;
        font-size: 0.9rem;
        min-height: 70px;
    }

    .guestbook-form button {
        padding: 0.45rem 1rem;
        font-size: 0.9rem;
    }

    .guestbook-login {
        padding: 1.25rem;
        font-size: 0.9rem;
    }

    .entry-item {
        padding: 0.85rem;
    }

    .entry-header {
        font-size: 0.8rem;
    }

    .entry-content {
        font-size: 0.9rem;
    }
}

/* ===== Responsive: 480px (Small Phone) ===== */
@media (max-width: 480px) {
    .guestbook-container {
        margin: 1rem auto;
        padding: 0 0.75rem;
    }

    .guestbook-title {
        font-size: 1.2rem;
    }

    .guestbook-form textarea {
        padding: 0.6rem;
        font-size: 0.85rem;
    }

    .entry-item {
        padding: 0.75rem;
    }

    .entry-header {
        flex-direction: column;
        gap: 0.25rem;
        align-items: flex-start;
    }

    .entry-content {
        font-size: 0.85rem;
    }
}