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

body {
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    min-height: 100vh;
    padding: 20px;
}

.page {
    display: block;
}

.page.hidden {
    display: none;
}

/* ログインページ */
.login-container {
    max-width: 400px;
    margin: 100px auto;
    background: white;
    padding: 40px;
    border-radius: 10px;
    box-shadow: 0 10px 30px rgba(0, 0, 0, 0.3);
}

.login-container h1 {
    text-align: center;
    color: #333;
    margin-bottom: 30px;
    font-size: 28px;
}

.form-group {
    margin-bottom: 20px;
}

.form-group label {
    display: block;
    margin-bottom: 8px;
    color: #555;
    font-weight: 500;
}

.form-group input {
    width: 100%;
    padding: 12px;
    border: 2px solid #ddd;
    border-radius: 5px;
    font-size: 16px;
    transition: border-color 0.3s;
}

.form-group input:focus {
    outline: none;
    border-color: #667eea;
}

.error-message {
    color: #e74c3c;
    font-size: 14px;
    margin-bottom: 15px;
    min-height: 20px;
    display: none;
}

.error-message.show {
    display: block;
}

/* ボタン */
.btn {
    padding: 12px 24px;
    border: none;
    border-radius: 5px;
    font-size: 16px;
    cursor: pointer;
    transition: all 0.3s;
    font-weight: 500;
}

.btn-primary {
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    color: white;
    width: 100%;
}

.btn-primary:hover {
    transform: translateY(-2px);
    box-shadow: 0 5px 15px rgba(102, 126, 234, 0.4);
}

.btn-secondary {
    background: #6c757d;
    color: white;
}

.btn-secondary:hover {
    background: #5a6268;
}

.btn-danger {
    background: #e74c3c;
    color: white;
    padding: 8px 16px;
    font-size: 14px;
}

.btn-danger:hover {
    background: #c0392b;
}

.btn-success {
    background: #27ae60;
    color: white;
    padding: 8px 16px;
    font-size: 14px;
}

.btn-success:hover {
    background: #229954;
}

/* メインページ */
header {
    background: white;
    padding: 20px 40px;
    border-radius: 10px;
    margin-bottom: 30px;
    display: flex;
    justify-content: space-between;
    align-items: center;
    box-shadow: 0 5px 15px rgba(0, 0, 0, 0.1);
}

header h1 {
    color: #333;
    font-size: 24px;
}

main {
    max-width: 1200px;
    margin: 0 auto;
}

.upload-section {
    background: white;
    padding: 30px;
    border-radius: 10px;
    margin-bottom: 30px;
    box-shadow: 0 5px 15px rgba(0, 0, 0, 0.1);
}

.upload-section h2 {
    color: #333;
    margin-bottom: 20px;
    font-size: 20px;
}

.upload-area {
    border: 3px dashed #667eea;
    border-radius: 10px;
    padding: 40px;
    text-align: center;
    transition: all 0.3s;
    background: #f8f9fa;
}

.upload-area:hover {
    border-color: #764ba2;
    background: #f0f0f0;
}

.upload-area.drag-over {
    border-color: #27ae60;
    background: #e8f5e9;
}

.upload-area p {
    color: #666;
    margin: 10px 0;
}

#fileInput {
    display: none;
}

.files-section {
    background: white;
    padding: 30px;
    border-radius: 10px;
    box-shadow: 0 5px 15px rgba(0, 0, 0, 0.1);
}

.files-section h2 {
    color: #333;
    margin-bottom: 20px;
    font-size: 20px;
}

.file-list {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(300px, 1fr));
    gap: 20px;
}

.file-item {
    background: #f8f9fa;
    padding: 20px;
    border-radius: 8px;
    border: 2px solid #e9ecef;
    transition: all 0.3s;
}

.file-item:hover {
    border-color: #667eea;
    transform: translateY(-2px);
    box-shadow: 0 5px 15px rgba(0, 0, 0, 0.1);
}

.file-name {
    font-weight: 600;
    color: #333;
    margin-bottom: 10px;
    word-break: break-all;
    font-size: 16px;
}

.file-info {
    color: #666;
    font-size: 14px;
    margin-bottom: 15px;
}

.file-actions {
    display: flex;
    gap: 10px;
}

.empty-message {
    text-align: center;
    color: #999;
    padding: 40px;
    font-size: 18px;
}

/* レスポンシブ */
@media (max-width: 768px) {
    .login-container {
        margin: 50px 20px;
        padding: 30px 20px;
    }

    header {
        flex-direction: column;
        gap: 15px;
        padding: 20px;
    }

    .file-list {
        grid-template-columns: 1fr;
    }
}