:root {
    --primary-color: #4361ee;
    --secondary-color: #3f37c9;
    --text-color: #2b2d42;
    --bg-color: #f8f9fa;
    --card-bg: #ffffff;
    --navbar-bg: rgba(255, 255, 255, 0.9);
    --shadow: 0 4px 6px rgba(0, 0, 0, 0.1);
    --transition: all 0.3s cubic-bezier(0.25, 0.8, 0.25, 1);
}

[data-theme="dark"] {
    --primary-color: #4895ef;
    --secondary-color: #4361ee;
    --text-color: #f8f9fa;
    --bg-color: #121212;
    --card-bg: #1e1e1e;
    --navbar-bg: rgba(30, 30, 30, 0.9);
    --shadow: 0 4px 6px rgba(0, 0, 0, 0.3);
}

* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
    transition: background-color 0.3s ease, color 0.3s ease;
}

body {
    background-color: var(--bg-color);
    color: var(--text-color);
    font-family: 'Segoe UI', system-ui, -apple-system, sans-serif;
    line-height: 1.6;
    min-height: 100vh;
}

.navbar {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    background-color: var(--navbar-bg);
    backdrop-filter: blur(10px);
    padding: 1rem 0;
    z-index: 1000;
    box-shadow: var(--shadow);
    transition: var(--transition);
}

.navbar nav ul {
    list-style: none;
    display: flex;
    justify-content: center;
    align-items: center;
    gap: 2rem;
    padding: 0 1rem;
}

.navbar nav ul li a {
    color: var(--text-color);
    text-decoration: none;
    font-size: 1rem;
    font-weight: 500;
    padding: 0.5rem 1rem;
    border-radius: 0.5rem;
    transition: var(--transition);
}

.navbar nav ul li a:hover {
    color: var(--primary-color);
    background-color: rgba(67, 97, 238, 0.1);
}

.theme-toggle {
    position: fixed;
    top: 1rem;
    right: 1rem;
    width: 3rem;
    height: 3rem;
    border-radius: 50%;
    background-color: var(--primary-color);
    color: white;
    border: none;
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    z-index: 1001;
    box-shadow: var(--shadow);
    transition: var(--transition);
}

.theme-toggle:hover {
    transform: scale(1.1);
}

.theme-toggle i {
    font-size: 1.2rem;
}

.message-section {
    margin-top: 6rem;
    width: 90%;
    max-width: 1200px;
    margin-left: auto;
    margin-right: auto;
    padding: 2rem;
    display: grid;
    gap: 2rem;
}

.message-block {
    background-color: var(--card-bg);
    padding: 2rem;
    border-radius: 1rem;
    box-shadow: var(--shadow);
    transition: var(--transition);
    border: 1px solid rgba(67, 97, 238, 0.1);
}

.message-block:hover {
    transform: translateY(-5px);
    box-shadow: 0 10px 20px rgba(0, 0, 0, 0.1);
    border-color: rgba(67, 97, 238, 0.3);
}

.message-block h2 {
    font-size: 1.5rem;
    color: var(--primary-color);
    margin-bottom: 1rem;
    font-weight: 600;
}

.message-block p {
    font-size: 1rem;
    line-height: 1.7;
    color: var(--text-color);
    margin-bottom: 1rem;
    opacity: 0.9;
}

.message-block a {
    color: var(--primary-color);
    text-decoration: none;
    font-weight: 500;
    transition: var(--transition);
}

.message-block a:hover {
    color: var(--secondary-color);
    text-decoration: underline;
}

.block-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    cursor: pointer;
}

.toggle-btn {
    background-color: var(--primary-color);
    color: white;
    border: none;
    padding: 0.5rem 1rem;
    border-radius: 0.5rem;
    cursor: pointer;
    font-weight: 500;
    transition: var(--transition);
}

.toggle-btn:hover {
    background-color: var(--secondary-color);
    transform: scale(1.05);
}

.block-content {
    overflow: hidden;
    transition: max-height 0.5s cubic-bezier(0.4, 0, 0.2, 1), opacity 0.3s ease, padding 0.3s ease;
    max-height: 1000px;
    opacity: 1;
    padding-top: 1rem;
}

.block-content.collapsed {
    max-height: 0;
    opacity: 0;
    padding: 0;
    margin: 0;
}

/* 表单样式 */
#messageForm {
    background-color: var(--card-bg);
    padding: 2rem;
    border-radius: 1rem;
    box-shadow: var(--shadow);
    margin-top: 6rem;
}

#messageForm label {
    display: block;
    margin-bottom: 0.5rem;
    font-weight: 500;
    color: var(--text-color);
}

#messageForm input,
#messageForm textarea {
    width: 100%;
    padding: 0.75rem;
    margin-bottom: 1rem;
    border: 1px solid rgba(67, 97, 238, 0.2);
    border-radius: 0.5rem;
    background-color: var(--card-bg);
    color: var(--text-color);
    transition: var(--transition);
}

#messageForm input:focus,
#messageForm textarea:focus {
    outline: none;
    border-color: var(--primary-color);
    box-shadow: 0 0 0 2px rgba(67, 97, 238, 0.2);
}

#messageForm button {
    padding: 0.75rem 1.5rem;
    background-color: var(--primary-color);
    color: white;
    border: none;
    border-radius: 0.5rem;
    cursor: pointer;
    font-weight: 500;
    transition: var(--transition);
}

#messageForm button:hover {
    background-color: var(--secondary-color);
    transform: translateY(-2px);
}

/* 响应式设计 */
@media (max-width: 768px) {
    .navbar nav ul {
        gap: 0.5rem;
    }

    .navbar nav ul li a {
        padding: 0.5rem;
        font-size: 0.9rem;
    }

    .message-section {
        padding: 1rem;
        width: 95%;
    }

    .message-block {
        padding: 1.5rem;
    }

    .theme-toggle {
        width: 2.5rem;
        height: 2.5rem;
        top: 0.75rem;
        right: 0.75rem;
    }
}