/* ============================================
   基本スタイル
   ============================================ */

body {
    font-family: "Helvetica Neue", Arial, sans-serif;
    background-color: #f5f5f5;
    color: #333;
    margin: 0;
    padding: 0;
}

/* ナビゲーションバー */
nav {
    background-color: #2c3e50;
    padding: 10px 20px;
}

nav a {
    color: white;
    text-decoration: none;
    margin-right: 15px;
}

nav a:hover {
    text-decoration: underline;
}

.user-info {
    color: #bdc3c7;
    float: right;
}

/* コンテナ */
.container {
    max-width: 800px;
    margin: 20px auto;
    padding: 20px;
    background-color: white;
    border-radius: 5px;
    box-shadow: 0 2px 5px rgba(0, 0, 0, 0.1);
}

/* 見出し */
h1 {
    color: #2c3e50;
    border-bottom: 2px solid #3498db;
    padding-bottom: 10px;
}

/* フォーム */
label {
    display: block;
    margin-top: 15px;
    margin-bottom: 5px;
    font-weight: bold;
}

input[type="text"],
input[type="password"],
input[type="date"],
select {
    width: 100%;
    padding: 8px;
    margin-bottom: 10px;
    border: 1px solid #ddd;
    border-radius: 4px;
    box-sizing: border-box;
}

button[type="submit"] {
    background-color: #3498db;
    color: white;
    padding: 10px 20px;
    border: none;
    border-radius: 4px;
    cursor: pointer;
    margin-top: 10px;
}

button[type="submit"]:hover {
    background-color: #2980b9;
}

/* テーブル */
table {
    width: 100%;
    border-collapse: collapse;
    margin-top: 15px;
}

th, td {
    border: 1px solid #ddd;
    padding: 10px;
    text-align: left;
}

th {
    background-color: #3498db;
    color: white;
}

tr:nth-child(even) {
    background-color: #f2f2f2;
}

/* リンク */
a {
    color: #3498db;
    text-decoration: none;
}

a:hover {
    text-decoration: underline;
}

/* フラッシュメッセージ */
.flash {
    padding: 10px;
    margin: 10px 20px;
    border-radius: 4px;
}

.flash.success {
    background-color: #d4edda;
    color: #155724;
    border: 1px solid #c3e6cb;
}

.flash.danger {
    background-color: #f8d7da;
    color: #721c24;
    border: 1px solid #f5c6cb;
}

.flash.warning {
    background-color: #fff3cd;
    color: #856404;
    border: 1px solid #ffeeba;
}

.flash.info {
    background-color: #d1ecf1;
    color: #0c5460;
    border: 1px solid #bee5eb;
}

/* 課題状態 */
.status-done {
    color: green;
    font-weight: bold;
}

.status-pending {
    color: red;
    font-weight: bold;
}