:root {
    --primary-bg: #0f172a;
    --card-bg: rgba(255, 255, 255, 0.05);
    --glass-border: rgba(255, 255, 255, 0.1);
    --accent-blue: #38bdf8;
    --accent-green: #10b981;
    --accent-orange: #f59e0b;
    --text-main: #f8fafc;
    --text-dim: #94a3b8;
}

* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
    font-family: 'Inter', system-ui, -apple-system, sans-serif;
}

body {
    background: var(--primary-bg);
    background: radial-gradient(circle at top left, #1e293b, #0f172a);
    color: var(--text-main);
    min-height: 100vh;
    display: flex;
    flex-direction: column;
}

.glass {
    background: var(--card-bg);
    backdrop-filter: blur(12px);
    -webkit-backdrop-filter: blur(12px);
    border: 1px solid var(--glass-border);
    border-radius: 16px;
    box-shadow: 0 8px 32px 0 rgba(0, 0, 0, 0.37);
}

/* Login Page */
.login-container {
    display: flex;
    justify-content: center;
    align-items: center;
    height: 100vh;
}

.login-card {
    width: 400px;
    padding: 2.5rem;
    animation: fadeIn 0.8s ease-out;
}

.login-card h1 {
    font-size: 1.8rem;
    margin-bottom: 0.5rem;
    text-align: center;
    background: linear-gradient(to right, #38bdf8, #818cf8);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
}

.login-card p {
    color: var(--text-dim);
    text-align: center;
    margin-bottom: 2rem;
    font-size: 0.9rem;
}

/* Form Styles */
.form-group {
    margin-bottom: 1.5rem;
}

.form-group label {
    display: block;
    margin-bottom: 0.5rem;
    font-size: 0.85rem;
    color: var(--text-dim);
}

input[type="text"], input[type="password"] {
    width: 100%;
    padding: 0.75rem 1rem;
    background: rgba(255, 255, 255, 0.05);
    border: 1px solid var(--glass-border);
    border-radius: 8px;
    color: white;
    outline: none;
    transition: all 0.3s;
}

input[type="text"]:focus, input[type="password"]:focus {
    border-color: var(--accent-blue);
    background: rgba(255, 255, 255, 0.08);
}

.btn {
    width: 100%;
    padding: 0.75rem;
    border: none;
    border-radius: 8px;
    font-weight: 600;
    cursor: pointer;
    transition: all 0.3s;
}

.btn-primary {
    background: linear-gradient(135deg, #38bdf8, #2563eb);
    color: white;
}

.btn-primary:hover {
    transform: translateY(-2px);
    box-shadow: 0 4px 12px rgba(37, 99, 235, 0.4);
}

/* Dashboard */
.nav {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 1.5rem 2rem;
}

.logo {
    font-size: 1.5rem;
    font-weight: 800;
    background: linear-gradient(to right, #38bdf8, #818cf8);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
}

.user-info {
    display: flex;
    align-items: center;
    gap: 1rem;
    color: var(--text-dim);
}

.logout-link {
    color: var(--text-dim);
    text-decoration: none;
    font-size: 0.9rem;
}

.logout-link:hover {
    color: white;
}

main {
    flex: 1;
    padding: 2rem;
    max-width: 1000px;
    margin: 0 auto;
    width: 100%;
}

.input-section {
    margin-bottom: 3rem;
    text-align: center;
}

.input-box {
    display: flex;
    gap: 0.5rem;
    max-width: 600px;
    margin: 1.5rem auto 0;
}

.input-box input {
    flex: 1;
    font-size: 1rem;
}

.input-box .btn {
    width: 120px;
}

.list-section h2 {
    margin-bottom: 1.5rem;
    font-size: 1.4rem;
}

.submission-list {
    width: 100%;
    border-collapse: separate;
    border-spacing: 0 0.75rem;
}

.submission-list th {
    text-align: left;
    padding: 0.5rem 1rem;
    color: var(--text-dim);
    font-weight: 400;
    font-size: 0.85rem;
}

.submission-row {
    transition: transform 0.2s;
}

.submission-row td {
    background: var(--card-bg);
    padding: 1rem;
    border-top: 1px solid var(--glass-border);
    border-bottom: 1px solid var(--glass-border);
}

.submission-row td:first-child {
    border-left: 1px solid var(--glass-border);
    border-radius: 12px 0 0 12px;
}

.submission-row td:last-child {
    border-right: 1px solid var(--glass-border);
    border-radius: 0 12px 12px 0;
    text-align: right;
}

.badge {
    padding: 0.25rem 0.75rem;
    border-radius: 20px;
    font-size: 0.75rem;
    font-weight: 600;
}

.badge-pending {
    background: rgba(245, 158, 11, 0.1);
    color: var(--accent-orange);
    border: 1px solid rgba(245, 158, 11, 0.2);
}

.badge-completed {
    background: rgba(16, 185, 129, 0.1);
    color: var(--accent-green);
    border: 1px solid rgba(16, 185, 129, 0.2);
}

.btn-download {
    background: var(--accent-green);
    color: white;
    padding: 0.4rem 1rem;
    border-radius: 6px;
    text-decoration: none;
    font-size: 0.8rem;
    display: inline-block;
}

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

.error-msg {
    background: rgba(239, 68, 68, 0.1);
    color: #ef4444;
    padding: 0.75rem;
    border-radius: 8px;
    margin-bottom: 1.5rem;
    font-size: 0.85rem;
    text-align: center;
    border: 1px solid rgba(239, 68, 68, 0.2);
}
/* Media Queries for Mobile Responsiveness */
@media (max-width: 768px) {
    .login-card {
        width: 90%;
        padding: 2rem 1.5rem;
    }

    .nav {
        padding: 1rem;
        flex-direction: row; /* 保持水平但优化间距 */
    }

    .user-info {
        gap: 0.5rem;
    }

    .user-info span {
        display: none; /* 在手机端隐藏欢迎语 */
    }

    .logo {
        font-size: 1.2rem;
    }

    main {
        padding: 1rem;
    }

    .input-box {
        flex-direction: column;
        gap: 0.75rem;
    }

    .input-box input {
        width: 100%;
    }

    .input-box .btn {
        width: 100%;
        padding: 0.8rem;
    }

    /* Mobile Table: Convert to Cards */
    .submission-list thead {
        display: none; /* 隐藏表头 */
    }

    .submission-list, .submission-list tbody, .submission-row, .submission-row td {
        display: block;
        width: 100%;
    }

    .submission-row {
        margin-bottom: 1rem;
        border: 1px solid var(--glass-border);
        border-radius: 12px;
        background: var(--card-bg);
        overflow: hidden;
    }

    .submission-row td {
        background: transparent;
        border: none;
        padding: 0.75rem 1rem;
        display: flex;
        justify-content: space-between;
        align-items: center;
        text-align: right;
        border-bottom: 1px solid rgba(255, 255, 255, 0.05);
    }

    .submission-row td:last-child {
        border-bottom: none;
    }

    .submission-row td:before {
        content: attr(data-label);
        float: left;
        font-weight: 600;
        color: var(--text-dim);
        font-size: 0.8rem;
    }

    .submission-row td:first-child, .submission-row td:last-child {
        border-radius: 0;
    }
}