* {
    box-sizing: border-box;
}

body {
    margin: 0;
    font-family: "Segoe UI", Arial, sans-serif;
    color: #1a1a2e;
    background: #f5f6fa;
}

.hero {
    background: linear-gradient(135deg, #1a1a2e, #4361ee);
    color: #fff;
    padding: 1.5rem 2rem 4rem;
}

nav {
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.logo {
    font-weight: bold;
    font-size: 1.3rem;
}

.nav-links a {
    color: #fff;
    text-decoration: none;
    margin-left: 1rem;
    border: 1px solid rgba(255, 255, 255, 0.6);
    padding: 0.4rem 0.9rem;
    border-radius: 6px;
}

.nav-links a:hover {
    background: rgba(255, 255, 255, 0.15);
}

.hero-content {
    max-width: 800px;
    margin: 3rem auto 0;
    text-align: center;
}

.hero-content h1 {
    font-size: 3rem;
    margin-bottom: 0.5rem;
}

.tagline {
    font-size: 1.3rem;
    opacity: 0.9;
}

.meta {
    list-style: none;
    padding: 0;
    display: flex;
    justify-content: center;
    gap: 2rem;
    margin-top: 1.5rem;
}

main {
    max-width: 800px;
    margin: -2rem auto 3rem;
    background: #fff;
    padding: 2rem;
    border-radius: 10px;
    box-shadow: 0 10px 30px rgba(0, 0, 0, 0.08);
}

.api-info code {
    background: #eef1f8;
    padding: 0.2rem 0.5rem;
    border-radius: 4px;
}

footer {
    text-align: center;
    padding: 1.5rem;
    color: #666;
}

.login-container {
    max-width: 380px;
    margin: 4rem auto;
    background: #fff;
    padding: 2rem;
    border-radius: 10px;
    box-shadow: 0 10px 30px rgba(0, 0, 0, 0.08);
    text-align: center;
}

.login-container form {
    display: flex;
    flex-direction: column;
    text-align: left;
    margin-top: 1.5rem;
}

.login-container label {
    margin-top: 0.8rem;
    font-weight: 600;
    font-size: 0.9rem;
}

.login-container input {
    padding: 0.6rem;
    margin-top: 0.3rem;
    border: 1px solid #ccc;
    border-radius: 6px;
}

.login-container button {
    margin-top: 1.5rem;
    padding: 0.7rem;
    background: #4361ee;
    color: #fff;
    border: none;
    border-radius: 6px;
    cursor: pointer;
    font-weight: 600;
}

.login-container button:hover {
    background: #324ac9;
}

.demo-hint {
    font-size: 0.85rem;
    color: #555;
}

.error {
    color: #d64545;
    font-weight: 600;
}

.back-link {
    display: inline-block;
    margin-top: 1.2rem;
    color: #4361ee;
    text-decoration: none;
}