:root {
    --nav-bg: #002c52;
    --primary-blue: #002c52;
    --active-teal: #00b0b9;
    --text-dark: #001e38;
    --text-gray: #4a5568;
    --border-color: #e2e8f0;
    --bg-white: #ffffff;
}

body {
    font-family: 'Segoe UI', Roboto, Helvetica, Arial, sans-serif;
    margin: 0;
    padding: 0;
    color: var(--text-dark);
    line-height: 1.5;
    background-color: var(--bg-white);
}

/* Top Nav */
.top-nav {
    background-color: var(--nav-bg);
    padding: 1rem 2rem;
    height: 60px;
    display: flex;
    align-items: center;
}

.nav-content {
    display: flex;
    gap: 30px;
    align-items: center;
}

.logo {
    height: 24px;
    filter: brightness(0) invert(1);
}

.brand-name {
    color: white;
    font-size: 20px;
    font-weight: 500;
    margin-right: 15px;
}

/* Layout */
.main-layout {
    display: flex;
    max-width: 1200px;
    margin: 60px auto;
    padding: 0 40px;
}

/* Sidebar */
.sidebar {
    width: 200px;
    flex-shrink: 0;
}

.stepper-vertical {
    display: flex;
    flex-direction: column;
    gap: 40px;
    position: relative;
}

.stepper-vertical::before {
    content: '';
    position: absolute;
    left: 4px;
    top: 10px;
    bottom: 10px;
    width: 1px;
    background-color: #cbd5e0;
    z-index: 0;
}

.step-item {
    display: flex;
    gap: 15px;
    position: relative;
    z-index: 1;
}

.step-indicator {
    width: 10px;
    height: 10px;
    border-radius: 50%;
    background-color: #cbd5e0;
    margin-top: 6px;
    flex-shrink: 0;
}

.step-item.active .step-indicator {
    background-color: var(--active-teal);
    box-shadow: 0 0 0 3px rgba(0, 176, 185, 0.2);
}

.step-item.completed .step-indicator {
    background-color: var(--active-teal);
}

.step-txt {
    display: flex;
    flex-direction: column;
}

.step-label {
    font-size: 13px;
    font-weight: 700;
    color: #a0aec0;
}

.step-item.active .step-label {
    color: var(--active-teal);
}

.step-title {
    font-size: 12px;
    color: #a0aec0;
}

.step-item.active .step-title {
    color: var(--active-teal);
}

/* Main Content */
.content-area {
    flex-grow: 1;
    padding-left: 100px;
}

.form-wrapper {
    max-width: 700px;
}

.main-title {
    font-size: 48px;
    font-weight: 700;
    margin: 0 0 20px 0;
    color: var(--text-dark);
}

.description {
    font-size: 14px;
    color: var(--text-gray);
    margin-bottom: 60px;
    line-height: 1.6;
}

.section-title {
    font-size: 42px;
    font-weight: 700;
    margin-bottom: 40px;
}

/* Form Styles */
.form-group {
    margin-bottom: 25px;
}

.form-row {
    display: flex;
    gap: 20px;
}

.form-group.half {
    flex: 1;
}

label {
    display: block;
    font-size: 14px;
    font-weight: 600;
    margin-bottom: 8px;
}

label.required::before {
    content: '* ';
    color: #e53e3e;
}

input,
select {
    width: 100%;
    padding: 12px 16px;
    border: 1px solid #dcdfe6;
    border-radius: 4px;
    font-size: 14px;
    box-sizing: border-box;
}

input::placeholder {
    color: #c0c4cc;
}

.input-hint {
    display: block;
    font-size: 12px;
    color: #718096;
    margin-top: 8px;
}

/* Actions */
.footer-actions {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-top: 60px;
}

.back-link {
    color: var(--text-dark);
    font-weight: 600;
    text-decoration: underline;
    font-size: 16px;
}

.btn-next {
    background-color: var(--primary-blue);
    color: white;
    padding: 12px 30px;
    border-radius: 30px;
    font-size: 16px;
    font-weight: 600;
    border: none;
    cursor: pointer;
    display: flex;
    align-items: center;
    gap: 10px;
    margin-left: auto;
}

.btn-next:hover {
    opacity: 0.9;
}

.summary {
    background: #f7fafc;
    padding: 20px;
    border-radius: 8px;
}

/* --- Mobile Responsive Rules --- */
@media (max-width: 768px) {
    .main-layout {
        flex-direction: column;
        margin: 20px auto;
        padding: 0 20px;
    }

    .sidebar {
        width: 100%;
        margin-bottom: 30px;
    }

    .stepper-vertical {
        flex-direction: row;
        justify-content: space-between;
        gap: 0;
    }

    .stepper-vertical::before {
        height: 1px;
        width: 100%;
        top: 10px;
        left: 0;
    }

    .step-item {
        flex-direction: column;
        align-items: center;
        gap: 5px;
        flex: 1;
    }

    .step-indicator {
        margin-top: 5px;
    }

    .step-txt {
        align-items: center;
    }

    .step-title {
        display: none;
        /* 移动端隐藏小标题，仅保留 Step 1/2... */
    }

    .content-area {
        padding-left: 0;
    }

    .main-title {
        font-size: 32px;
    }

    .section-title {
        font-size: 28px;
        margin-bottom: 30px;
    }

    .form-row {
        flex-direction: column;
        gap: 0;
    }
}