* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

body {
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    background: linear-gradient(135deg, #0f172a 0%, #1e293b 50%, #334155 100%);
    min-height: 100vh;
    color: #e2e8f0;
    line-height: 1.6;
}

.container {
    max-width: 500px;
    margin: 0 auto;
    padding: 20px;
    min-height: 100vh;
    display: flex;
    flex-direction: column;
    justify-content: center;
}

.header {
    text-align: center;
    margin-bottom: 40px;
}

.logo {
    font-size: 2.5rem;
    font-weight: 700;
    background: linear-gradient(135deg, #60a5fa, #3b82f6, #1d4ed8);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
    margin-bottom: 10px;
}

.subtitle {
    color: #94a3b8;
    font-size: 1.1rem;
    font-weight: 300;
}

.form-container {
    background: rgba(30, 41, 59, 0.8);
    backdrop-filter: blur(20px);
    border: 1px solid rgba(148, 163, 184, 0.1);
    border-radius: 20px;
    padding: 40px;
    box-shadow: 0 25px 50px -12px rgba(0, 0, 0, 0.5);
}

.form-group {
    margin-bottom: 25px;
}

.form-group label {
    display: block;
    margin-bottom: 8px;
    color: #f1f5f9;
    font-weight: 500;
    font-size: 0.95rem;
}

.form-group input {
    width: 100%;
    padding: 15px 20px;
    background: rgba(15, 23, 42, 0.6);
    border: 2px solid rgba(148, 163, 184, 0.2);
    border-radius: 12px;
    color: #e2e8f0;
    font-size: 1rem;
    transition: all 0.3s ease;
}

.form-group input:focus {
    outline: none;
    border-color: #3b82f6;
    background: rgba(15, 23, 42, 0.8);
    box-shadow: 0 0 0 3px rgba(59, 130, 246, 0.1);
}

.form-group input::placeholder {
    color: #64748b;
}

.checkbox-group {
    margin: 30px 0;
    padding: 20px;
    background: rgba(15, 23, 42, 0.4);
    border-radius: 12px;
    border: 1px solid rgba(148, 163, 184, 0.1);
}

.checkbox-item {
    display: flex;
    align-items: flex-start;
    margin-bottom: 15px;
}

.checkbox-item:last-child {
    margin-bottom: 0;
}

.checkbox-item input[type="checkbox"] {
    width: 20px;
    height: 20px;
    margin-right: 12px;
    margin-top: 2px;
    accent-color: #3b82f6;
    flex-shrink: 0;
}

.checkbox-item label {
    color: #cbd5e1;
    font-size: 0.9rem;
    line-height: 1.5;
    cursor: pointer;
}

.checkbox-item a {
    color: #60a5fa;
    text-decoration: none;
    transition: color 0.3s ease;
}

.checkbox-item a:hover {
    color: #93c5fd;
    text-decoration: underline;
}

.button-group {
    display: flex;
    gap: 15px;
    margin-top: 30px;
}

.btn {
    flex: 1;
    padding: 15px 30px;
    border: none;
    border-radius: 12px;
    font-size: 1rem;
    font-weight: 600;
    cursor: pointer;
    transition: all 0.3s ease;
    text-decoration: none;
    text-align: center;
    display: inline-block;
}

.btn-primary {
    background: linear-gradient(135deg, #3b82f6, #1d4ed8);
    color: white;
    box-shadow: 0 10px 25px -5px rgba(59, 130, 246, 0.3);
}

.btn-primary:hover {
    background: linear-gradient(135deg, #2563eb, #1e40af);
    transform: translateY(-2px);
    box-shadow: 0 15px 35px -5px rgba(59, 130, 246, 0.4);
}

.btn-primary:disabled {
    background: #374151;
    color: #6b7280;
    cursor: not-allowed;
    transform: none;
    box-shadow: none;
}

.btn-secondary {
    background: rgba(148, 163, 184, 0.1);
    color: #cbd5e1;
    border: 2px solid rgba(148, 163, 184, 0.2);
}

.btn-secondary:hover {
    background: rgba(148, 163, 184, 0.2);
    border-color: rgba(148, 163, 184, 0.3);
    transform: translateY(-1px);
}

.footer {
    text-align: center;
    margin-top: 40px;
    padding-top: 20px;
    border-top: 1px solid rgba(148, 163, 184, 0.1);
    color: #64748b;
    font-size: 0.85rem;
}

/* レスポンシブデザイン */
@media (max-width: 768px) {
    .container {
        padding: 15px;
        justify-content: flex-start;
        padding-top: 40px;
    }

    .logo {
        font-size: 2rem;
    }

    .form-container {
        padding: 30px 25px;
        border-radius: 15px;
    }

    .button-group {
        flex-direction: column;
    }

    .btn {
        padding: 18px 30px;
    }
}

@media (max-width: 480px) {
    .container {
        padding: 10px;
        padding-top: 30px;
    }

    .form-container {
        padding: 25px 20px;
    }

    .logo {
        font-size: 1.8rem;
    }

    .subtitle {
        font-size: 1rem;
    }
}

/* アニメーション */
.form-container {
    animation: fadeInUp 0.6s ease-out;
}

@keyframes fadeInUp {
    from {
        opacity: 0;
        transform: translateY(30px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

.form-group input {
    animation: fadeInUp 0.6s ease-out;
    animation-fill-mode: both;
}

.message {
    padding: 12px;
    margin-bottom: 20px;
    border-radius: 6px;
    font-weight: 500;
}
.message.success {
    background-color: #d1fae5;
    color: #065f46;
    border: 1px solid #a7f3d0;
}
.message.error {
    background-color: #fee2e2;
    color: #991b1b;
    border: 1px solid #fca5a5;
}

.form-group:nth-child(1) input { animation-delay: 0.1s; }
.form-group:nth-child(2) input { animation-delay: 0.2s; }
.form-group:nth-child(3) input { animation-delay: 0.3s; }
.form-group:nth-child(4) input { animation-delay: 0.4s; }