body {
    margin: 0;
    background: #18191a;
    color: #f1f1f1;
    font-family: 'Segoe UI', Arial, sans-serif;
    min-height: 100vh;
    display: flex;
    flex-direction: column;
}
a {
    color: #63b3ed;
    text-decoration: none;
    transition: color .2s;
}
a:hover {
    color: #ffd166;
}
.navbar {
    background: #23272f;
    padding: 0.5em 2em;
    display: flex;
    align-items: center;
    justify-content: space-between;
    box-shadow: 0 2px 8px rgba(0,0,0,.25);
    position: sticky;
    top: 0;
    z-index: 10;
}
.navbar .logo {
    font-size: 1.6em;
    font-weight: bold;
    letter-spacing: 2px;
    color: #ffd166;
}
.navbar ul {
    display: flex;
    gap: 1.5em;
    list-style: none;
    margin: 0;
    padding: 0;
}
.navbar li {
    display: flex;
    align-items: center;
}
.navbar li a {
    font-size: 1em;
    padding: .5em 1em;
    border-radius: 5px;
    transition: background .2s;
}
.navbar li a.active,
.navbar li a:hover {
    background: #343a40;
}
.container {
    max-width: 500px;
    margin: 3em auto 1.5em;
    background: #23272f;
    padding: 2em 2em 1.5em 2em;
    border-radius: 15px;
    box-shadow: 0 4px 24px rgba(0,0,0,0.55);
    min-width: 320px;
}
h1, h2 {
    color: #ffd166;
    margin-bottom: .8em;
    text-align: center;
}
form {
    display: flex;
    flex-direction: column;
    gap: 1.1em;
}
input[type="text"], input[type="password"] {
    background: #18191a;
    color: #eee;
    border: 1px solid #444;
    border-radius: 7px;
    padding: 0.8em 1em;
    font-size: 1em;
    transition: border-color 0.2s;
}
input[type="text"]:focus, input[type="password"]:focus {
    border-color: #ffd166;
    outline: none;
}
button {
    background: #ffd166;
    color: #23272f;
    border: none;
    border-radius: 7px;
    padding: 0.8em;
    font-size: 1.05em;
    font-weight: bold;
    cursor: pointer;
    transition: background 0.2s;
}
button:hover {
    background: #ffbb33;
}
.error, .success {
    padding: .7em 1em;
    border-radius: 6px;
    margin-bottom: .5em;
    font-weight: bold;
}
.error { background: #ff7171; color: #23272f; }
.success { background: #63e69e; color: #23272f; }
footer {
    background: #23272f;
    color: #999;
    text-align: center;
    font-size: .98em;
    padding: 1.2em 0 .9em 0;
    margin-top: auto;
    letter-spacing: 1px;
    border-top: 1px solid #222;
}
@media (max-width: 650px) {
    .container { margin: 1em .5em; padding: 1.2em 0.5em; }
    .navbar { flex-direction: column; align-items: flex-start; padding: 1em; }
    .navbar ul { flex-direction: column; gap: 0.5em; margin-top: .7em; }
}