html,
body,
#app {
    min-height: 100%;
}

body {
    margin: 0;
    background: #f4f7fb;
    color: #172335;
    font-family: Inter, "Segoe UI", Arial, sans-serif;
}

a {
    color: inherit;
}

.app-shell {
    display: grid;
    min-height: 100vh;
    grid-template-columns: 280px minmax(0, 1fr);
}

.sidebar {
    display: flex;
    flex-direction: column;
    background: #002d4f;
    color: #fff;
    padding: 22px 18px;
}

.brand {
    display: grid;
    gap: 8px;
    margin-bottom: 26px;
}

.brand img {
    width: 170px;
    height: auto;
}

.slogan {
    color: rgba(255, 255, 255, 0.72);
    font-size: 0.82rem;
}

.sidebar nav {
    display: grid;
    gap: 4px;
}

.sidebar nav a {
    border-radius: 6px;
    color: rgba(255, 255, 255, 0.82);
    padding: 10px 12px;
    text-decoration: none;
}

.sidebar nav a.active,
.sidebar nav a:hover {
    background: rgba(118, 188, 33, 0.18);
    color: #fff;
}

.nav-separator {
    height: 1px;
    margin: 12px 0;
    background: rgba(255, 255, 255, 0.16);
}

.user-card {
    display: grid;
    gap: 8px;
    margin-top: auto;
    border-top: 1px solid rgba(255, 255, 255, 0.14);
    padding-top: 16px;
    font-size: 0.9rem;
}

.user-card span {
    color: rgba(255, 255, 255, 0.7);
}

.app-content {
    min-width: 0;
    padding: 30px;
}

.page-header {
    display: flex;
    align-items: flex-end;
    justify-content: space-between;
    gap: 16px;
    margin-bottom: 20px;
}

.page-header h1 {
    margin: 0;
    color: #002d4f;
    font-size: 1.7rem;
    font-weight: 700;
}

.page-header p {
    max-width: 820px;
    margin: 6px 0 0;
    color: #526274;
}

.toolbar-row {
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 12px;
    margin-bottom: 14px;
}

.grid-panel,
.content-panel {
    background: #fff;
    border: 1px solid #dbe3ee;
    border-radius: 8px;
    padding: 18px;
    box-shadow: 0 8px 24px rgba(16, 42, 67, 0.06);
}

.course-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(260px, 1fr));
    gap: 16px;
}

.course-card {
    display: grid;
    overflow: hidden;
    min-height: 330px;
    border: 1px solid #dbe3ee;
    border-radius: 8px;
    background: #fff;
}

.course-card img {
    width: 100%;
    aspect-ratio: 16 / 9;
    object-fit: cover;
    background: #e8edf5;
}

.course-card-body {
    display: grid;
    gap: 10px;
    padding: 16px;
}

.course-code {
    color: #76bc21;
    font-size: 0.78rem;
    font-weight: 700;
    letter-spacing: 0;
    text-transform: uppercase;
}

.course-card h2 {
    margin: 0;
    color: #002d4f;
    font-size: 1.06rem;
}

.course-card p {
    margin: 0;
    color: #526274;
}

.login-page {
    display: grid;
    min-height: 100vh;
    place-items: center;
    background: linear-gradient(135deg, #002d4f 0%, #17496d 54%, #76bc21 100%);
    padding: 24px;
}

.login-panel {
    width: min(420px, 100%);
    border-radius: 8px;
    background: #fff;
    padding: 28px;
    box-shadow: 0 20px 60px rgba(0, 45, 79, 0.28);
}

.login-panel img {
    width: 180px;
    margin-bottom: 22px;
}

.login-panel h1 {
    margin: 0 0 18px;
    color: #002d4f;
    font-size: 1.5rem;
}

.form-grid {
    display: grid;
    gap: 16px;
}

.error-text {
    color: #b42318;
}

@media (max-width: 820px) {
    .app-shell {
        grid-template-columns: 1fr;
    }

    .sidebar {
        position: static;
    }

    .app-content {
        padding: 18px;
    }
}