:root {
    --bg-dark: #0f172a;       /* 深空蓝背景 */
    --card-bg: #1e293b;       /* 卡片背景 */
    --primary: #06b6d4;       /* 科技青 */
    --primary-hover: #0891b2;
    --text-main: #f8fafc;     /* 亮白文字 */
    --text-sub: #94a3b8;      /* 灰色副标题 */
    --border: #334155;
}

* { box-sizing: border-box; margin: 0; padding: 0; }

body {
    font-family: 'Inter', -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif;
    background-color: var(--bg-dark);
    color: var(--text-main);
    line-height: 1.6;
}

/* 导航栏 */
.navbar {
    background: rgba(15, 23, 42, 0.9);
    backdrop-filter: blur(10px);
    border-bottom: 1px solid var(--border);
    padding: 1rem 0;
    position: sticky;
    top: 0;
    z-index: 100;
}
.nav-container {
    max-width: 1100px;
    margin: 0 auto;
    padding: 0 1.5rem;
    display: flex;
    justify-content: space-between;
    align-items: center;
}
.logo {
    font-size: 1.25rem;
    font-weight: 700;
    color: var(--primary);
    text-decoration: none;
    letter-spacing: 1px;
}
.nav-links a {
    color: var(--text-sub);
    text-decoration: none;
    margin-left: 2rem;
    font-size: 0.95rem;
    transition: color 0.3s;
}
.nav-links a:hover, .nav-links a.active {
    color: var(--primary);
}

/* 通用容器 */
.container {
    max-width: 1100px;
    margin: 0 auto;
    padding: 4rem 1.5rem;
}

/* Hero 区域 */
.hero {
    text-align: center;
    padding: 6rem 1rem;
    background: radial-gradient(circle at center, #1e293b 0%, #0f172a 70%);
}
.hero h1 {
    font-size: 3rem;
    margin-bottom: 1rem;
    background: linear-gradient(to right, #fff, #94a3b8);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
}
.hero p {
    color: var(--text-sub);
    font-size: 1.2rem;
    max-width: 600px;
    margin: 0 auto 2rem;
}
.btn-primary {
    display: inline-block;
    background: var(--primary);
    color: #000;
    padding: 0.8rem 2rem;
    border-radius: 4px;
    text-decoration: none;
    font-weight: 600;
    transition: all 0.3s;
}
.btn-primary:hover {
    background: var(--primary-hover);
    transform: translateY(-2px);
    box-shadow: 0 4px 12px rgba(6, 182, 212, 0.3);
}

/* 卡片网格 */
.grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 2rem;
    margin-top: 2rem;
}
.card {
    background: var(--card-bg);
    border: 1px solid var(--border);
    border-radius: 8px;
    padding: 2rem;
    transition: transform 0.3s, border-color 0.3s;
}
.card:hover {
    transform: translateY(-5px);
    border-color: var(--primary);
}
.card-tag {
    display: inline-block;
    font-size: 0.75rem;
    padding: 0.25rem 0.75rem;
    border-radius: 20px;
    background: rgba(6, 182, 212, 0.1);
    color: var(--primary);
    margin-bottom: 1rem;
}
.card h3 {
    font-size: 1.25rem;
    margin-bottom: 0.5rem;
}
.card p {
    color: var(--text-sub);
    font-size: 0.95rem;
    margin-bottom: 1.5rem;
}
.card-meta {
    font-size: 0.85rem;
    color: #64748b;
    border-top: 1px solid var(--border);
    padding-top: 1rem;
    display: flex;
    justify-content: space-between;
}

/* 表单样式 */
.form-group {
    margin-bottom: 1.5rem;
}
.form-label {
    display: block;
    margin-bottom: 0.5rem;
    color: var(--text-sub);
    font-size: 0.9rem;
}
.form-input, .form-textarea {
    width: 100%;
    padding: 0.8rem;
    background: #020617;
    border: 1px solid var(--border);
    border-radius: 4px;
    color: white;
    font-family: inherit;
}
.form-input:focus, .form-textarea:focus {
    outline: none;
    border-color: var(--primary);
}
.flash-message {
    background: rgba(6, 182, 212, 0.1);
    border: 1px solid var(--primary);
    color: var(--primary);
    padding: 1rem;
    border-radius: 4px;
    margin-bottom: 2rem;
    text-align: center;
}

footer {
    text-align: center;
    padding: 3rem;
    color: #475569;
    font-size: 0.9rem;
    border-top: 1px solid var(--border);
    margin-top: 4rem;
}