:root {
    --primary-color: #6366f1;
    --primary-hover: #4f46e5;
    --bg-dark: #0f172a;
    --card-bg: #1e293b;
    --text-main: #f8fafc;
    --text-muted: #94a3b8;
    --border-color: #334155;
    --accent-glow: rgba(99, 102, 241, 0.15);
}

* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
    font-family: 'Inter', -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif;
}

body {
    background-color: var(--bg-dark);
    color: var(--text-main);
    line-height: 1.6;
    padding: 2rem 1rem;
    min-height: 100vh;
    display: flex;
    justify-content: center;
}

.container {
    width: 100%;
    max-width: 800px;
}

header {
    text-align: center;
    margin-bottom: 3rem;
}

header h1 {
    font-size: 2.5rem;
    font-weight: 800;
    background: linear-gradient(to right, #818cf8, #c084fc);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    margin-bottom: 0.5rem;
}

header p {
    color: var(--text-muted);
}

/* 表单样式 */
.form-card {
    background: var(--card-bg);
    border: 1px solid var(--border-color);
    border-radius: 1rem;
    padding: 2rem;
    margin-bottom: 3rem;
    box-shadow: 0 10px 25px -5px rgba(0, 0, 0, 0.3);
}

.form-group {
    margin-bottom: 1.5rem;
}

label {
    display: block;
    margin-bottom: 0.5rem;
    font-size: 0.875rem;
    font-weight: 500;
    color: var(--text-muted);
}

input[type="text"],
textarea {
    width: 100%;
    background: #0f172a;
    border: 1px solid var(--border-color);
    border-radius: 0.5rem;
    padding: 0.75rem 1rem;
    color: white;
    font-size: 1rem;
    transition: all 0.2s;
}

input[type="text"]:focus,
textarea:focus {
    outline: none;
    border-color: var(--primary-color);
    box-shadow: 0 0 0 4px var(--accent-glow);
}

button {
    background: var(--primary-color);
    color: white;
    border: none;
    padding: 0.75rem 1.5rem;
    border-radius: 0.5rem;
    font-weight: 600;
    cursor: pointer;
    transition: all 0.2s;
    width: 100%;
}

button:hover {
    background: var(--primary-hover);
    transform: translateY(-1px);
}

/* 留言列表样式 */
.message-list {
    display: flex;
    flex-direction: column;
    gap: 1.5rem;
}

.message-card {
    background: var(--card-bg);
    border-left: 4px solid var(--primary-color);
    border-radius: 0.75rem;
    padding: 1.5rem;
    animation: fadeIn 0.5s ease-out forwards;
}

.message-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 1rem;
}

.username {
    font-weight: 700;
    color: #818cf8;
}

.timestamp {
    font-size: 0.8rem;
    color: var(--text-muted);
}

.content {
    white-space: pre-wrap;
    word-break: break-word;
}

@keyframes fadeIn {
    from { opacity: 0; transform: translateY(10px); }
    to { opacity: 1; transform: translateY(0); }
}

footer {
    text-align: center;
    margin-top: 4rem;
    color: var(--text-muted);
    font-size: 0.875rem;
}