:root {
    --primary: #0D47A1;
    --primary-dark: #002171;
    --primary-light: #5472D3;
    --accent: #E53935;
    --bg: #F0F4F9;
    --card-bg: #FFFFFF;
    --text-primary: #1A1A2E;
    --text-secondary: #5A5A7A;
    --text-muted: #8E8EA0;
    --border: #E0E5EC;
    --shadow: 0 12px 40px rgba(0,0,0,0.08);
    --radius: 22px;
}

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

body {
    font-family: 'Noto Sans KR', -apple-system, BlinkMacSystemFont, sans-serif;
    background: linear-gradient(145deg, #E8EDF5 0%, #DCE3EC 100%);
    display: flex;
    justify-content: center;
    align-items: center;
    min-height: 100vh;
    color: var(--text-primary);
    -webkit-tap-highlight-color: transparent;
}

.app-container {
    width: 100%;
    max-width: 400px;
    min-height: 100vh;
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    padding: 24px 20px;
    position: relative;
}

/* 배경 장식 */
.bg-decor {
    position: absolute;
    top: -80px;
    left: -40px;
    width: 200px;
    height: 200px;
    background: radial-gradient(circle, rgba(13,71,161,0.15) 0%, transparent 70%);
    border-radius: 50%;
    z-index: 0;
}

/* 인증 카드 */
.auth-card {
    width: 100%;
    background: var(--card-bg);
    border-radius: var(--radius);
    padding: 32px 24px 28px;
    box-shadow: var(--shadow);
    z-index: 1;
    position: relative;
}

/* 로고 */
.logo-section {
    text-align: center;
    margin-bottom: 24px;
}

.logo-icon {
    font-size: 40px;
    margin-bottom: 8px;
}

.logo-text {
    font-size: 26px;
    font-weight: 900;
    letter-spacing: -1px;
    color: var(--primary-dark);
}

.logo-sub {
    font-size: 13px;
    color: var(--text-muted);
    margin-top: 4px;
}

/* 탭 전환 */
.tab-switch {
    display: flex;
    position: relative;
    background: #F0F2F6;
    border-radius: 14px;
    padding: 4px;
    margin-bottom: 28px;
}

.tab-btn {
    flex: 1;
    background: transparent;
    border: none;
    padding: 12px;
    font-size: 15px;
    font-weight: 700;
    color: var(--text-muted);
    border-radius: 12px;
    cursor: pointer;
    transition: color 0.25s;
    position: relative;
    z-index: 1;
}

.tab-btn.active {
    color: var(--primary-dark);
}

.tab-indicator {
    position: absolute;
    top: 4px;
    bottom: 4px;
    left: 4px;
    width: calc(50% - 4px);
    background: white;
    border-radius: 12px;
    box-shadow: 0 2px 8px rgba(0,0,0,0.06);
    transition: transform 0.3s cubic-bezier(0.4, 0, 0.2, 1);
}

/* 폼 */
.auth-form {
    display: none;
    flex-direction: column;
    gap: 18px;
}

.auth-form.active {
    display: flex;
}

.input-group {
    display: flex;
    flex-direction: column;
    gap: 6px;
}

.input-group label {
    font-size: 13px;
    font-weight: 600;
    color: var(--text-secondary);
}

.input-group input {
    width: 100%;
    height: 48px;
    border: 1.5px solid var(--border);
    border-radius: 12px;
    padding: 0 14px;
    font-size: 15px;
    font-weight: 500;
    color: var(--text-primary);
    background: #FAFBFD;
    outline: none;
    transition: border 0.2s, box-shadow 0.2s;
}

.input-group input:focus {
    border-color: var(--primary-light);
    box-shadow: 0 0 0 3px rgba(84,114,211,0.1);
}

.error-msg {
    font-size: 11px;
    color: var(--accent);
    min-height: 16px;
    visibility: hidden;
}

.input-group.error input {
    border-color: var(--accent);
}

.input-group.error .error-msg {
    visibility: visible;
}

/* 약관 */
.terms-group {
    margin-top: 4px;
}

.checkbox-label {
    display: flex;
    align-items: flex-start;
    gap: 8px;
    font-size: 13px;
    color: var(--text-secondary);
    cursor: pointer;
}

.checkbox-label input {
    display: none;
}

.checkmark {
    width: 20px;
    height: 20px;
    border: 2px solid var(--border);
    border-radius: 6px;
    display: inline-block;
    position: relative;
    flex-shrink: 0;
    margin-top: 1px;
}

.checkbox-label input:checked + .checkmark {
    background: var(--primary);
    border-color: var(--primary);
}

.checkbox-label input:checked + .checkmark::after {
    content: '';
    position: absolute;
    left: 5px;
    top: 1px;
    width: 6px;
    height: 12px;
    border: solid white;
    border-width: 0 2px 2px 0;
    transform: rotate(45deg);
}

.terms-text a {
    color: var(--primary);
    font-weight: 600;
    text-decoration: none;
}

/* 제출 버튼 */
.submit-btn {
    width: 100%;
    height: 50px;
    background: var(--primary);
    color: white;
    border: none;
    border-radius: 14px;
    font-size: 16px;
    font-weight: 700;
    cursor: pointer;
    transition: background 0.2s, transform 0.1s;
    margin-top: 4px;
}

.submit-btn:active {
    transform: scale(0.98);
    background: var(--primary-dark);
}

/* 폼 하단 */
.form-footer {
    text-align: center;
    font-size: 13px;
    color: var(--text-muted);
    display: flex;
    justify-content: center;
    gap: 8px;
    margin-top: 4px;
}

.form-footer a {
    color: var(--primary);
    font-weight: 600;
    text-decoration: none;
}

.divider {
    color: var(--border);
}

/* 소셜 로그인 */
.social-login {
    text-align: center;
    margin-top: 8px;
}

.social-text {
    font-size: 12px;
    color: var(--text-muted);
    display: block;
    margin-bottom: 12px;
    position: relative;
}

.social-text::before,
.social-text::after {
    content: '';
    position: absolute;
    top: 50%;
    width: 30%;
    height: 1px;
    background: var(--border);
}

.social-text::before { left: 0; }
.social-text::after { right: 0; }

.social-icons {
    display: flex;
    justify-content: center;
    gap: 16px;
}

.social-btn {
    width: 42px;
    height: 42px;
    border-radius: 12px;
    border: none;
    font-size: 18px;
    font-weight: 800;
    color: white;
    cursor: pointer;
}

.social-btn.kakao { background: #FEE500; color: #3C1E1E; }
.social-btn.naver { background: #03C75A; }
.social-btn.google { background: #F1F3F4; color: #444; border: 1px solid #ddd; }

/* 하단 */
.footer-text {
    font-size: 11px;
    color: var(--text-muted);
    margin-top: 20px;
    z-index: 1;
}

/* 반응형 */
@media (max-width: 360px) {
    .auth-card {
        padding: 24px 18px 22px;
    }
}



/* 정책 텍스트 영역 */
.policy-box {
    background: #F8FAFC;
    border: 1px solid var(--border);
    border-radius: 14px;
    padding: 16px;
    margin-bottom: 24px;
    max-height: 320px;
    overflow-y: auto;
    font-size: 13px;
    line-height: 1.7;
    color: var(--text-secondary);
}
.policy-box h2 {
    font-size: 16px;
    font-weight: 700;
    color: var(--text-primary);
    margin-bottom: 12px;
}
.policy-box h3 {
    font-size: 14px;
    font-weight: 600;
    color: var(--primary-dark);
    margin-top: 16px;
    margin-bottom: 6px;
}
.policy-box p,
.policy-box li {
    margin-bottom: 6px;
}
.policy-box ul {
    padding-left: 18px;
    list-style-type: disc;
}
/* 폼 요소 */
.input-group {
    display: flex;
    flex-direction: column;
    gap: 6px;
    margin-bottom: 18px;
}
.input-group label {
    font-size: 13px;
    font-weight: 600;
    color: var(--text-secondary);
}
.input-group input {
    width: 100%;
    height: 48px;
    border: 1.5px solid var(--border);
    border-radius: 12px;
    padding: 0 14px;
    font-size: 15px;
    font-weight: 500;
    color: var(--text-primary);
    background: #FAFBFD;
    outline: none;
    transition: border 0.2s, box-shadow 0.2s;
}
.input-group input:focus {
    border-color: var(--primary-light);
    box-shadow: 0 0 0 3px rgba(84,114,211,0.1);
}
.error-msg {
    display: none;
    font-size: 11px;
    color: var(--accent);
    min-height: 16px;
    visibility: hidden;
}
.input-group.error input {
    border-color: var(--accent);
}
.input-group.error .error-msg {
    visibility: visible;
}
.submit-btn {
    width: 100%;
    height: 50px;
    background: var(--primary);
    color: white;
    border: none;
    border-radius: 14px;
    font-size: 16px;
    font-weight: 700;
    cursor: pointer;
    transition: background 0.2s, transform 0.1s;
    margin-top: 4px;
}
.submit-btn:active {
    transform: scale(0.98);
    background: var(--primary-dark);
}
.submit-btn.secondary {
    background: #E0E7FF;
    color: var(--primary-dark);
}
.agreement-reminder {
    background: #E8F0FE;
    border-radius: 10px;
    padding: 10px 14px;
    font-size: 12px;
    color: var(--primary-dark);
    display: flex;
    align-items: center;
    gap: 6px;
    margin-bottom: 20px;
}
.footer-text {
    font-size: 11px;
    color: var(--text-muted);
    margin-top: 20px;
    z-index: 1;
    text-align: center;
}