/* ============================================================ */
/* Week 3: UX 개선 - 애니메이션 & 트랜지션 */
/* ============================================================ */

/* 전역 트랜지션 설정 */
* {
    transition-timing-function: cubic-bezier(0.4, 0, 0.2, 1);
}

/* ============================================================ */
/* 로딩 스피너 */
/* ============================================================ */

.loading-spinner {
    display: inline-block;
    width: 20px;
    height: 20px;
    border: 3px solid rgba(255, 255, 255, 0.3);
    border-radius: 50%;
    border-top-color: var(--color-white);
    animation: spin 0.8s linear infinite;
}

.loading-spinner.large {
    width: 40px;
    height: 40px;
    border-width: 4px;
}

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

/* 로딩 메시지 (타이핑 애니메이션) */
.loading-dots::after {
    content: '';
    animation: loadingDots 1.5s steps(4, end) infinite;
}

@keyframes loadingDots {
    0%, 20% {
        content: '';
    }
    40% {
        content: '.';
    }
    60% {
        content: '..';
    }
    80%, 100% {
        content: '...';
    }
}

/* ============================================================ */
/* 메시지 등장 애니메이션 */
/* ============================================================ */

.message {
    animation: messageSlideIn 0.3s ease-out;
}

.message.bot {
    animation: messageSlideInLeft 0.3s ease-out;
}

.message.user {
    animation: messageSlideInRight 0.3s ease-out;
}

@keyframes messageSlideIn {
    from {
        opacity: 0;
        transform: translateY(10px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

@keyframes messageSlideInLeft {
    from {
        opacity: 0;
        transform: translateX(-20px);
    }
    to {
        opacity: 1;
        transform: translateX(0);
    }
}

@keyframes messageSlideInRight {
    from {
        opacity: 0;
        transform: translateX(20px);
    }
    to {
        opacity: 1;
        transform: translateX(0);
    }
}

/* ============================================================ */
/* 버튼 인터랙션 효과 */
/* ============================================================ */

/* Ripple 효과 */
.ripple {
    position: relative;
    overflow: hidden;
}

.ripple::after {
    content: '';
    position: absolute;
    top: 50%;
    left: 50%;
    width: 0;
    height: 0;
    border-radius: 50%;
    background: rgba(255, 255, 255, 0.5);
    transform: translate(-50%, -50%);
    transition: width 0.6s, height 0.6s;
}

.ripple:active::after {
    width: 200px;
    height: 200px;
}

/* 버튼 호버 효과 강화 */
@media (hover: hover) {
    .send-button:hover,
    .confirm-button:hover {
        box-shadow: 0 6px 20px rgba(102, 126, 234, 0.4);
        transform: translateY(-2px) scale(1.02);
    }

    .photo-button:hover {
        background-color: rgba(0, 0, 0, 0.05);
        transform: scale(1.1);
    }
}

/* 버튼 클릭 효과 */
button:active,
.send-button:active,
.photo-button:active,
.confirm-button:active {
    transform: scale(0.95);
}

/* ============================================================ */
/* 입력 포커스 효과 */
/* ============================================================ */

.message-input:focus,
.confirm-card-food-input:focus {
    animation: inputFocusPulse 0.3s ease-out;
}

@keyframes inputFocusPulse {
    0% {
        box-shadow: 0 0 0 0 rgba(102, 126, 234, 0.4);
    }
    50% {
        box-shadow: 0 0 0 8px rgba(102, 126, 234, 0);
    }
    100% {
        box-shadow: 0 2px 12px rgba(102, 126, 234, 0.3);
    }
}

/* ============================================================ */
/* 카드 등장 애니메이션 (향상) */
/* ============================================================ */

.nutrition-card,
.confirm-card {
    animation: cardSlideUp 0.4s cubic-bezier(0.34, 1.56, 0.64, 1);
}

@keyframes cardSlideUp {
    from {
        opacity: 0;
        transform: translateY(30px) scale(0.95);
    }
    to {
        opacity: 1;
        transform: translateY(0) scale(1);
    }
}

/* ============================================================ */
/* 스켈레톤 로딩 UI */
/* ============================================================ */

.skeleton {
    background: linear-gradient(
        90deg,
        rgba(255, 255, 255, 0.1) 25%,
        rgba(255, 255, 255, 0.2) 50%,
        rgba(255, 255, 255, 0.1) 75%
    );
    background-size: 200% 100%;
    animation: skeletonLoading 1.5s ease-in-out infinite;
    border-radius: var(--border-radius-md);
}

@keyframes skeletonLoading {
    0% {
        background-position: 200% 0;
    }
    100% {
        background-position: -200% 0;
    }
}

.skeleton-card {
    width: 100%;
    height: 200px;
}

.skeleton-text {
    width: 80%;
    height: 20px;
    margin: var(--spacing-sm) 0;
}

.skeleton-text.short {
    width: 50%;
}

/* ============================================================ */
/* 페이드 인/아웃 */
/* ============================================================ */

.fade-in {
    animation: fadeIn 0.3s ease-in;
}

.fade-out {
    animation: fadeOut 0.3s ease-out;
}

@keyframes fadeIn {
    from {
        opacity: 0;
    }
    to {
        opacity: 1;
    }
}

@keyframes fadeOut {
    from {
        opacity: 1;
    }
    to {
        opacity: 0;
    }
}

/* ============================================================ */
/* 에러 Shake 애니메이션 */
/* ============================================================ */

.shake {
    animation: shake 0.4s cubic-bezier(0.36, 0.07, 0.19, 0.97);
}

@keyframes shake {
    0%, 100% {
        transform: translateX(0);
    }
    10%, 30%, 50%, 70%, 90% {
        transform: translateX(-5px);
    }
    20%, 40%, 60%, 80% {
        transform: translateX(5px);
    }
}

/* ============================================================ */
/* 성공 체크 애니메이션 */
/* ============================================================ */

.success-check {
    width: 60px;
    height: 60px;
    border-radius: 50%;
    background: linear-gradient(135deg, #11998e 0%, #38ef7d 100%);
    display: flex;
    align-items: center;
    justify-content: center;
    animation: successPopIn 0.5s cubic-bezier(0.68, -0.55, 0.265, 1.55);
}

.success-check::after {
    content: '✓';
    color: white;
    font-size: 2rem;
    font-weight: bold;
    animation: checkmarkDraw 0.3s 0.2s ease-out forwards;
    opacity: 0;
}

@keyframes successPopIn {
    0% {
        transform: scale(0);
        opacity: 0;
    }
    50% {
        transform: scale(1.1);
    }
    100% {
        transform: scale(1);
        opacity: 1;
    }
}

@keyframes checkmarkDraw {
    to {
        opacity: 1;
    }
}

/* ============================================================ */
/* 스크롤 부드럽게 */
/* ============================================================ */

html {
    scroll-behavior: smooth;
}

.messages {
    scroll-behavior: smooth;
}

/* ============================================================ */
/* 숫자 카운트업 효과 (선택사항) */
/* ============================================================ */

.count-up {
    animation: countUp 0.8s ease-out;
}

@keyframes countUp {
    from {
        transform: translateY(20px);
        opacity: 0;
    }
    to {
        transform: translateY(0);
        opacity: 1;
    }
}

/* ============================================================ */
/* 펄스 효과 (주목을 끌 때) */
/* ============================================================ */

.pulse {
    animation: pulse 2s cubic-bezier(0.4, 0, 0.6, 1) infinite;
}

@keyframes pulse {
    0%, 100% {
        opacity: 1;
    }
    50% {
        opacity: 0.7;
    }
}

/* ============================================================ */
/* 바운스 효과 */
/* ============================================================ */

.bounce {
    animation: bounce 1s ease infinite;
}

@keyframes bounce {
    0%, 20%, 50%, 80%, 100% {
        transform: translateY(0);
    }
    40% {
        transform: translateY(-10px);
    }
    60% {
        transform: translateY(-5px);
    }
}

/* ============================================================ */
/* 성능 최적화 */
/* ============================================================ */

/* GPU 가속 활성화 */
.nutrition-card,
.confirm-card,
.message,
.send-button,
.photo-button {
    will-change: transform, opacity;
}

/* 애니메이션 완료 후 will-change 제거 */
.animation-complete {
    will-change: auto;
}

/* ============================================================ */
/* 접근성: 모션 감소 설정 존중 */
/* ============================================================ */

@media (prefers-reduced-motion: reduce) {
    *,
    *::before,
    *::after {
        animation-duration: 0.01ms !important;
        animation-iteration-count: 1 !important;
        transition-duration: 0.01ms !important;
        scroll-behavior: auto !important;
    }
}