/* ========================================
   AI 자가진단 설문 — 미니멀 B&W 디자인
   ======================================== */

:root {
    --black: #0a0a0a;
    --white: #ffffff;
    --gray-50: #fafafa;
    --gray-100: #f5f5f5;
    --gray-200: #e5e5e5;
    --gray-300: #d4d4d4;
    --gray-400: #a3a3a3;
    --gray-500: #737373;
    --gray-600: #525252;
    --gray-700: #404040;
    --gray-800: #262626;
    --gray-900: #171717;
    --accent: #2563eb;
    --accent-light: #dbeafe;
    --font: 'Paperlogy', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
}

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

html {
    font-size: 16px;
    scroll-behavior: smooth;
    -webkit-text-size-adjust: 100%;
}

body {
    font-family: var(--font);
    font-weight: 500;
    color: var(--black);
    background: var(--white);
    line-height: 1.6;
    min-height: 100vh;
    overflow-x: hidden;
}

/* ========== INTRO SCREEN ========== */

.intro-screen {
    display: flex;
    flex-direction: column;
    justify-content: center;
    align-items: center;
    padding: 4rem 2rem 3rem;
    text-align: center;
    position: relative;
}

.intro-content {
    max-width: 560px;
}

.intro-label {
    font-size: 0.75rem;
    font-weight: 600;
    letter-spacing: 0.2em;
    text-transform: uppercase;
    color: var(--gray-500);
    margin-bottom: 2rem;
}

.intro-title {
    font-size: clamp(2.5rem, 8vw, 5rem);
    font-weight: 900;
    line-height: 1.1;
    letter-spacing: -0.03em;
    margin-bottom: 1.5rem;
    color: var(--black);
}

.intro-desc {
    font-size: 1.05rem;
    font-weight: 400;
    color: var(--gray-600);
    line-height: 1.8;
    margin-bottom: 2rem;
}

.intro-meta {
    display: flex;
    justify-content: center;
    align-items: center;
    gap: 0.75rem;
    font-size: 0.85rem;
    font-weight: 600;
    color: var(--gray-500);
    margin-bottom: 3rem;
}

.intro-meta .dot {
    width: 3px;
    height: 3px;
    background: var(--gray-400);
    border-radius: 50%;
}

.btn-start {
    display: inline-block;
    padding: 1rem 3rem;
    font-family: var(--font);
    font-size: 1rem;
    font-weight: 700;
    color: var(--white);
    background: var(--black);
    border: none;
    border-radius: 0;
    cursor: pointer;
    transition: all 0.3s ease;
    letter-spacing: 0.05em;
}

.btn-start:hover {
    background: var(--gray-800);
    transform: translateY(-2px);
    box-shadow: 0 8px 24px rgba(0,0,0,0.15);
}

.intro-footer {
    margin-top: 2rem;
    font-size: 0.7rem;
    color: var(--gray-400);
    font-weight: 300;
}

/* ========== SURVEY SCREEN ========== */

.survey-screen {
    max-width: 720px;
    margin: 0 auto;
    padding: 0 1.5rem 1rem;
}

/* Progress Bar */
.progress-container {
    position: sticky;
    top: 0;
    z-index: 100;
    background: var(--white);
    padding: 1.5rem 0 1rem;
    border-bottom: 1px solid var(--gray-100);
}

.progress-bar {
    width: 100%;
    height: 2px;
    background: var(--gray-200);
    overflow: hidden;
}

.progress-fill {
    height: 100%;
    width: 0%;
    background: var(--black);
    transition: width 0.5s ease;
}

.progress-info {
    display: flex;
    justify-content: space-between;
    margin-top: 0.5rem;
    font-size: 0.7rem;
    font-weight: 600;
    color: var(--gray-500);
    letter-spacing: 0.1em;
}

/* Step Header */
.step-header {
    padding: 3rem 0 2rem;
}

.step-number {
    display: inline-block;
    font-size: 0.7rem;
    font-weight: 700;
    letter-spacing: 0.15em;
    color: var(--gray-400);
    margin-bottom: 0.75rem;
}

.step-title {
    font-size: clamp(1.75rem, 5vw, 2.5rem);
    font-weight: 800;
    line-height: 1.2;
    letter-spacing: -0.02em;
    margin-bottom: 0.5rem;
}

.step-desc {
    font-size: 0.95rem;
    font-weight: 400;
    color: var(--gray-500);
}

/* Questions */
.question-group {
    display: flex;
    flex-direction: column;
    gap: 3rem;
}

.question {
    opacity: 1;
}

.q-label {
    display: block;
    font-size: 1rem;
    font-weight: 700;
    line-height: 1.7;
    margin-bottom: 1rem;
    color: var(--black);
}

.q-num {
    display: inline-block;
    font-size: 0.75rem;
    font-weight: 800;
    color: var(--gray-500);
    margin-right: 0.5rem;
    font-variant-numeric: tabular-nums;
}

.required {
    color: var(--black);
    font-weight: 800;
}

.q-hint {
    display: block;
    font-size: 0.8rem;
    font-weight: 500;
    color: var(--gray-500);
    margin-top: 0.25rem;
}

/* Text Input */
.input-text {
    width: 100%;
    padding: 0.875rem 0;
    font-family: var(--font);
    font-size: 1rem;
    font-weight: 500;
    color: var(--black);
    background: transparent;
    border: none;
    border-bottom: 2px solid var(--gray-300);
    outline: none;
    transition: border-color 0.3s ease;
}

.input-text::placeholder {
    color: var(--gray-400);
    font-weight: 400;
}

.input-text:focus {
    border-bottom-color: var(--black);
}

/* Radio Cards (for selections like 업종, 업무분야) */
.radio-group {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(160px, 1fr));
    gap: 0.5rem;
}

.radio-group--row {
    grid-template-columns: repeat(auto-fill, minmax(120px, 1fr));
}

.radio-card {
    display: flex;
    align-items: center;
    padding: 0.75rem 1rem;
    border: 1.5px solid var(--gray-200);
    cursor: pointer;
    transition: all 0.2s ease;
    font-size: 0.9rem;
    font-weight: 500;
    color: var(--gray-700);
}

.radio-card:hover {
    border-color: var(--gray-400);
}

.radio-card input {
    display: none;
}

.radio-card input:checked + span {
    font-weight: 700;
}

.radio-card:has(input:checked) {
    border-color: var(--black);
    background: var(--black);
    color: var(--white);
}

/* Scale Cards (1-5 scale) */
.scale-group {
    display: grid;
    grid-template-columns: repeat(5, 1fr);
    gap: 0.5rem;
}

.scale-card {
    display: flex;
    flex-direction: column;
    align-items: center;
    text-align: center;
    padding: 1rem 0.5rem;
    border: 1.5px solid var(--gray-200);
    cursor: pointer;
    transition: all 0.2s ease;
}

.scale-card:hover {
    border-color: var(--gray-400);
}

.scale-card input {
    display: none;
}

.scale-num {
    display: block;
    font-size: 1.25rem;
    font-weight: 800;
    color: var(--gray-400);
    margin-bottom: 0.5rem;
    transition: color 0.2s ease;
}

.scale-text {
    font-size: 0.7rem;
    font-weight: 500;
    color: var(--gray-600);
    line-height: 1.4;
    transition: color 0.2s ease;
}

.scale-card:has(input:checked) {
    border-color: var(--black);
    background: var(--black);
}

.scale-card:has(input:checked) .scale-num {
    color: var(--white);
}

.scale-card:has(input:checked) .scale-text {
    color: var(--gray-300);
}

/* Checkbox Cards */
.checkbox-group {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(180px, 1fr));
    gap: 0.5rem;
}

.check-card {
    display: flex;
    align-items: center;
    padding: 0.75rem 1rem;
    border: 1.5px solid var(--gray-200);
    cursor: pointer;
    transition: all 0.2s ease;
    font-size: 0.9rem;
    font-weight: 500;
    color: var(--gray-700);
}

.check-card:hover {
    border-color: var(--gray-400);
}

.check-card input {
    display: none;
}

.check-card:has(input:checked) {
    border-color: var(--black);
    background: var(--black);
    color: var(--white);
}

.check-card:has(input:checked) span {
    font-weight: 600;
}

/* Navigation Buttons */
.nav-buttons {
    display: flex;
    justify-content: center;
    gap: 1rem;
    padding: 2rem 1.5rem 3rem;
}

.btn-prev, .btn-next, .btn-submit {
    font-family: var(--font);
    font-size: 0.9rem;
    font-weight: 700;
    padding: 0.875rem 2.5rem;
    cursor: pointer;
    transition: all 0.2s ease;
    border: none;
    letter-spacing: 0.05em;
}

.btn-prev {
    background: transparent;
    color: var(--gray-500);
    border: 1px solid var(--gray-300);
}

.btn-prev:hover {
    color: var(--black);
    border-color: var(--black);
}

.btn-next {
    background: var(--black);
    color: var(--white);
}

.btn-next:hover {
    background: var(--gray-800);
    transform: translateY(-1px);
}

.btn-submit {
    background: var(--black);
    color: var(--white);
    padding: 0.875rem 3rem;
}

.btn-submit:hover {
    background: var(--gray-800);
    transform: translateY(-1px);
}

/* Validation Error */
.question.error .input-text {
    border-bottom-color: #dc2626;
}

.question.error .q-label {
    color: #dc2626;
}

.question.error .scale-group,
.question.error .radio-group,
.question.error .checkbox-group {
    outline: 1px solid #dc2626;
    outline-offset: 4px;
}

/* ========== LOADING SCREEN ========== */

.loading-screen {
    display: flex;
    justify-content: center;
    align-items: center;
    min-height: 100vh;
    text-align: center;
}

.loading-content {
    max-width: 400px;
}

.loading-spinner {
    width: 40px;
    height: 40px;
    border: 2px solid var(--gray-200);
    border-top-color: var(--black);
    border-radius: 50%;
    animation: spin 0.8s linear infinite;
    margin: 0 auto 2rem;
}

@keyframes spin {
    to { transform: rotate(360deg); }
}

.loading-text {
    font-size: 1.1rem;
    font-weight: 700;
    margin-bottom: 0.5rem;
}

.loading-sub {
    font-size: 0.85rem;
    font-weight: 300;
    color: var(--gray-500);
}

/* ========== RESPONSIVE ========== */

@media (max-width: 768px) {
    .survey-screen {
        padding: 0 1rem 5rem;
    }

    .scale-group {
        grid-template-columns: repeat(5, 1fr);
        gap: 0.25rem;
    }

    .scale-card {
        padding: 0.75rem 0.25rem;
    }

    .scale-num {
        font-size: 1rem;
    }

    .scale-text {
        font-size: 0.55rem;
    }

    .radio-group {
        grid-template-columns: repeat(auto-fill, minmax(140px, 1fr));
    }

    .checkbox-group {
        grid-template-columns: 1fr;
    }

    .nav-buttons {
        gap: 0.5rem;
        padding: 0.75rem 1rem;
    }

    .btn-prev, .btn-next, .btn-submit {
        padding: 0.75rem 1.5rem;
        font-size: 0.85rem;
    }
}

@media (max-width: 480px) {
    .intro-title {
        font-size: 2.25rem;
    }

    .step-header {
        padding: 2rem 0 1.5rem;
    }

    .question-group {
        gap: 2.5rem;
    }

    .scale-group {
        grid-template-columns: repeat(5, 1fr);
        gap: 0.2rem;
    }

    .scale-card {
        padding: 0.6rem 0.15rem;
    }

    .scale-text {
        font-size: 0.5rem;
    }

    .radio-group {
        grid-template-columns: 1fr 1fr;
    }
}

/* "기타" 입력창 */
.input-other {
    margin-top: 0.5rem;
    border-bottom-color: var(--gray-400);
}

/* 퀴즈형 라디오 그룹 */
.radio-group--quiz {
    grid-template-columns: repeat(auto-fill, minmax(140px, 1fr));
}

/* 더 밀집된 체크박스 그리드 */
.checkbox-group--dense {
    grid-template-columns: repeat(auto-fill, minmax(150px, 1fr));
}

/* 레벨별 체크카드 (Q28 AI 활용 수준) */
.checkbox-group--level {
    grid-template-columns: 1fr;
}

.check-card--level1 { border-left: 3px solid #d4d4d4; }
.check-card--level2 { border-left: 3px solid #a3a3a3; }
.check-card--level3 { border-left: 3px solid #737373; }
.check-card--level4 { border-left: 3px solid #404040; }
.check-card--level5 { border-left: 3px solid #171717; }
.check-card--level6 { border-left: 3px solid #0a0a0a; }

.check-card--low {
    opacity: 0.7;
}

.check-card--mid {
    opacity: 0.85;
}

/* ========== ANIMATIONS (GSAP classes) ========== */

.form-step {
    will-change: transform, opacity;
}

.fade-in {
    opacity: 0;
    transform: translateY(20px);
}