* {
    box-sizing: border-box;
}

body {
    margin: 0;
    font-family: Arial, Helvetica, sans-serif;
    background: #f4f6f8;
    color: #1f2933;
}

a {
    color: #0056b3;
    text-decoration: none;
}

a:hover {
    text-decoration: underline;
}

.page {
    max-width: 1100px;
    margin: 40px auto;
    padding: 0 20px;
}

.card {
    background: #ffffff;
    border-radius: 12px;
    padding: 24px;
    margin-bottom: 24px;
    box-shadow: 0 4px 18px rgba(0, 0, 0, 0.08);
}

.header {
    background: #ffffff;
    border-bottom: 1px solid #e5e7eb;
    padding: 18px 30px;
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.header-title {
    font-size: 20px;
    font-weight: bold;
}

.nav a {
    margin-left: 18px;
}

h1 {
    margin-top: 0;
    color: #111827;
}

h2 {
    color: #1f2937;
    margin-top: 28px;
}

input,
textarea,
select {
    width: 100%;
    max-width: 520px;
    padding: 10px;
    border: 1px solid #cbd5e1;
    border-radius: 8px;
    font-size: 15px;
}

button,
.button {
    display: inline-block;
    background: #0056b3;
    color: white;
    border: none;
    border-radius: 8px;
    padding: 10px 16px;
    font-size: 15px;
    cursor: pointer;
}

button:hover,
.button:hover {
    background: #003f86;
    text-decoration: none;
}

table {
    width: 100%;
    border-collapse: collapse;
    background: white;
}

th {
    background: #eef2f7;
    text-align: left;
}

th,
td {
    padding: 10px;
    border: 1px solid #d9e2ec;
}

.message-success {
    background: #e6f4ea;
    color: #1e7e34;
    padding: 12px;
    border-radius: 8px;
}

.message-error {
    background: #fdecea;
    color: #b00020;
    padding: 12px;
    border-radius: 8px;
}

.video-player {
    width: 100%;
    max-width: 960px;
    border-radius: 12px;
    background: #000;
}

.grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
    gap: 18px;
}

.stat {
    background: #f8fafc;
    padding: 18px;
    border-radius: 10px;
    border: 1px solid #e5e7eb;
}

.stat-number {
    font-size: 32px;
    font-weight: bold;
    color: #0056b3;
}

.small {
    color: #64748b;
    font-size: 14px;
}

.progress-bar {
    width: 100%;
    max-width: 420px;
    height: 14px;
    background: #e5e7eb;
    border-radius: 999px;
    overflow: hidden;
    margin: 8px 0 12px 0;
}

.progress-fill {
    height: 100%;
    background: #0056b3;
    border-radius: 999px;
}

.logo-link {
    display: flex;
    align-items: center;
    gap: 12px;
    color: inherit;
    text-decoration: none;
}

.logo {
    height: 42px;
    width: auto;
    display: block;
}

.header-title {
    display: flex;
    align-items: center;
}

@media (max-width: 768px) {
    .header {
        flex-direction: column;
        align-items: flex-start;
        gap: 12px;
        padding: 16px 20px;
    }

    .nav {
        display: flex;
        flex-wrap: wrap;
        gap: 10px;
    }

    .nav a {
        margin-left: 0;
    }

    .page {
        margin: 20px auto;
        padding: 0 12px;
    }

    .card {
        padding: 18px;
        border-radius: 10px;
    }

    .logo {
        height: 36px;
    }

    h1 {
        font-size: 24px;
    }

    h2 {
        font-size: 20px;
    }

    input,
    textarea,
    select {
        max-width: 100%;
    }

    .button,
    button {
        width: 100%;
        margin-bottom: 8px;
        text-align: center;
    }

    table {
        display: block;
        width: 100%;
        overflow-x: auto;
        white-space: nowrap;
    }

    th,
    td {
        font-size: 14px;
        padding: 8px;
    }

    .video-player {
        width: 100%;
        max-width: 100%;
    }

    .progress-bar {
        max-width: 100%;
    }
}