/* ==========================================
   Reset & Base Styles
   ========================================== */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

:root {
    /* カラーパレット */
    --color-primary: #D4AF37; /* ゴールド */
    --color-secondary: #F5E6D3; /* ベージュ */
    --color-accent: #FFB84D; /* 明るいゴールド */
    --color-white: #FFFFFF;
    --color-text: #5A4A3A;
    --color-text-light: #8B7355;
    --color-shadow: rgba(212, 175, 55, 0.2);
    
    /* グラデーション */
    --gradient-primary: linear-gradient(135deg, #F5E6D3 0%, #FFF8E7 50%, #FFE5B4 100%);
    --gradient-gold: linear-gradient(135deg, #D4AF37 0%, #FFB84D 100%);
    --gradient-overlay: linear-gradient(180deg, rgba(255, 255, 255, 0) 0%, rgba(245, 230, 211, 0.3) 100%);
    
    /* フォント */
    --font-primary: 'Noto Sans JP', sans-serif;
    --font-display: 'Pacifico', cursive;
    --font-handwriting: 'Caveat', cursive;
    
    /* スペーシング */
    --spacing-xs: 0.5rem;
    --spacing-sm: 1rem;
    --spacing-md: 2rem;
    --spacing-lg: 4rem;
    --spacing-xl: 6rem;
    
    /* ブレイクポイント */
    --breakpoint-sm: 576px;
    --breakpoint-md: 768px;
    --breakpoint-lg: 992px;
    --breakpoint-xl: 1200px;
}

html {
    scroll-behavior: smooth;
    font-size: 16px;
}

body {
    font-family: var(--font-primary);
    color: var(--color-text);
    background: var(--gradient-primary);
    line-height: 1.6;
    overflow-x: hidden;
}

.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 var(--spacing-md);
}

/* ==========================================
   Confetti Animation Container
   ========================================== */
#confetti-container {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    pointer-events: none;
    z-index: 9999;
    overflow: hidden;
}

.confetti {
    position: absolute;
    font-size: 1.5rem;
    animation: fall linear infinite;
    opacity: 0.8;
}

@keyframes fall {
    0% {
        transform: translateY(-10vh) rotate(0deg);
        opacity: 1;
    }
    100% {
        transform: translateY(110vh) rotate(360deg);
        opacity: 0.3;
    }
}

/* ==========================================
   Hero Section
   ========================================== */
.hero-section {
    position: relative;
    min-height: 100vh;
    display: flex;
    align-items: center;
    justify-content: center;
    text-align: center;
    overflow: hidden;
    background: var(--gradient-primary);
    background-attachment: fixed;
}

.hero-content {
    position: relative;
    z-index: 2;
    padding: var(--spacing-md);
    animation: fadeInUp 1s ease-out;
}

.birthday-badge {
    display: inline-flex;
    align-items: center;
    gap: var(--spacing-xs);
    background: var(--color-white);
    padding: var(--spacing-xs) var(--spacing-md);
    border-radius: 50px;
    box-shadow: 0 4px 20px var(--color-shadow);
    margin-bottom: var(--spacing-md);
    font-weight: 500;
    color: var(--color-primary);
    animation: bounceIn 1s ease-out 0.5s both;
}

.birthday-badge i {
    color: var(--color-accent);
    font-size: 1.2rem;
}

.main-title {
    margin-bottom: var(--spacing-md);
}

.title-line-1 {
    display: block;
    font-family: var(--font-display);
    font-size: clamp(2.5rem, 8vw, 5rem);
    color: var(--color-primary);
    line-height: 1.2;
    text-shadow: 2px 2px 4px rgba(0, 0, 0, 0.1);
    animation: slideInLeft 1s ease-out 0.7s both;
}

.title-line-2 {
    display: block;
    font-family: var(--font-display);
    font-size: clamp(3rem, 10vw, 6rem);
    background: var(--gradient-gold);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
    line-height: 1.2;
    animation: slideInRight 1s ease-out 0.9s both;
}

.hero-subtitle {
    font-size: clamp(1rem, 2.5vw, 1.3rem);
    color: var(--color-text-light);
    margin-bottom: var(--spacing-lg);
    animation: fadeIn 1s ease-out 1.1s both;
}

.scroll-indicator {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: var(--spacing-xs);
    color: var(--color-primary);
    font-size: 0.9rem;
    animation: bounce 2s ease-in-out infinite;
    cursor: pointer;
}

.scroll-indicator i {
    font-size: 1.5rem;
}

/* Hero Decorations */
.hero-decorations {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    pointer-events: none;
    z-index: 1;
}

.balloon {
    position: absolute;
    font-size: 3rem;
    animation: float 6s ease-in-out infinite;
}

.balloon-1 {
    top: 20%;
    left: 10%;
    animation-delay: 0s;
}

.balloon-2 {
    top: 60%;
    right: 15%;
    animation-delay: 1s;
}

.balloon-3 {
    top: 40%;
    left: 80%;
    animation-delay: 2s;
}

.star {
    position: absolute;
    font-size: 2rem;
    animation: twinkle 3s ease-in-out infinite;
}

.star-1 {
    top: 15%;
    right: 20%;
    animation-delay: 0s;
}

.star-2 {
    top: 70%;
    left: 20%;
    animation-delay: 1s;
}

.star-3 {
    top: 50%;
    right: 10%;
    animation-delay: 2s;
}

/* ==========================================
   Section Styles
   ========================================== */
section {
    padding: var(--spacing-xl) 0;
    position: relative;
}

.section-title {
    font-size: clamp(2rem, 5vw, 3rem);
    text-align: center;
    margin-bottom: var(--spacing-lg);
    color: var(--color-text);
    font-weight: 700;
}

.title-decoration {
    display: inline-block;
    font-size: 1.5rem;
    margin: 0 var(--spacing-sm);
}

/* ==========================================
   Reason Section
   ========================================== */
.reason-section {
    background: var(--color-white);
}

.reason-cards {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: var(--spacing-md);
    margin-top: var(--spacing-lg);
}

.reason-card {
    background: var(--gradient-primary);
    padding: var(--spacing-lg);
    border-radius: 20px;
    text-align: center;
    box-shadow: 0 10px 30px rgba(0, 0, 0, 0.1);
    transition: transform 0.3s ease, box-shadow 0.3s ease;
}

.reason-card:hover {
    transform: translateY(-10px);
    box-shadow: 0 15px 40px rgba(212, 175, 55, 0.3);
}

.card-icon {
    font-size: 4rem;
    margin-bottom: var(--spacing-md);
}

.reason-card h3 {
    font-size: 1.5rem;
    margin-bottom: var(--spacing-sm);
    color: var(--color-text);
}

.reason-card p {
    color: var(--color-text-light);
    line-height: 1.8;
}

/* ==========================================
   Message Section
   ========================================== */
.message-section {
    background: var(--gradient-overlay);
}

.message-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(300px, 1fr));
    gap: var(--spacing-md);
    margin-bottom: var(--spacing-xl);
}

.message-card {
    background: var(--color-white);
    padding: var(--spacing-md);
    border-radius: 15px;
    box-shadow: 0 5px 20px rgba(0, 0, 0, 0.08);
    border-left: 4px solid var(--color-primary);
    transition: transform 0.3s ease;
    animation: fadeInUp 0.6s ease-out both;
}

.message-card:hover {
    transform: translateY(-5px);
    box-shadow: 0 10px 30px rgba(0, 0, 0, 0.15);
}

.message-header {
    display: flex;
    align-items: center;
    gap: var(--spacing-sm);
    margin-bottom: var(--spacing-sm);
}

.message-avatar {
    width: 50px;
    height: 50px;
    border-radius: 50%;
    background: var(--gradient-gold);
    display: flex;
    align-items: center;
    justify-content: center;
    color: var(--color-white);
    font-weight: bold;
    font-size: 1.2rem;
}

.message-info h4 {
    font-size: 1.1rem;
    color: var(--color-text);
    margin-bottom: 0.2rem;
}

.message-relationship {
    font-size: 0.85rem;
    color: var(--color-text-light);
    display: inline-block;
    padding: 0.2rem 0.6rem;
    background: var(--color-secondary);
    border-radius: 20px;
}

.message-content {
    font-family: var(--font-handwriting);
    font-size: 1.2rem;
    line-height: 1.8;
    color: var(--color-text);
    padding: var(--spacing-sm) 0;
}

/* Message Form */
.message-form-container {
    max-width: 600px;
    margin: var(--spacing-xl) auto 0;
    background: var(--color-white);
    padding: var(--spacing-lg);
    border-radius: 20px;
    box-shadow: 0 10px 40px rgba(0, 0, 0, 0.1);
}

.form-title {
    font-size: 1.8rem;
    text-align: center;
    margin-bottom: var(--spacing-md);
    color: var(--color-primary);
}

.form-group {
    margin-bottom: var(--spacing-md);
}

.form-group label {
    display: flex;
    align-items: center;
    gap: var(--spacing-xs);
    font-weight: 500;
    margin-bottom: var(--spacing-xs);
    color: var(--color-text);
}

.form-group label i {
    color: var(--color-primary);
}

.form-group input,
.form-group select,
.form-group textarea {
    width: 100%;
    padding: var(--spacing-sm);
    border: 2px solid var(--color-secondary);
    border-radius: 10px;
    font-family: var(--font-primary);
    font-size: 1rem;
    transition: border-color 0.3s ease;
}

.form-group input:focus,
.form-group select:focus,
.form-group textarea:focus {
    outline: none;
    border-color: var(--color-primary);
}

.form-group textarea {
    resize: vertical;
    min-height: 120px;
}

.submit-btn {
    width: 100%;
    padding: var(--spacing-md);
    background: var(--gradient-gold);
    color: var(--color-white);
    border: none;
    border-radius: 50px;
    font-size: 1.1rem;
    font-weight: 600;
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    gap: var(--spacing-sm);
    transition: transform 0.3s ease, box-shadow 0.3s ease;
}

.submit-btn:hover {
    transform: translateY(-2px);
    box-shadow: 0 10px 30px rgba(212, 175, 55, 0.4);
}

.submit-btn:active {
    transform: translateY(0);
}

/* ==========================================
   Gallery Section
   ========================================== */
.gallery-section {
    background: var(--color-white);
}

.gallery-description {
    text-align: center;
    color: var(--color-text-light);
    font-size: 1.1rem;
    margin-bottom: var(--spacing-lg);
}

.gallery-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: var(--spacing-md);
    margin-bottom: var(--spacing-md);
}

.gallery-item {
    position: relative;
    aspect-ratio: 1;
    border-radius: 15px;
    overflow: hidden;
    box-shadow: 0 5px 20px rgba(0, 0, 0, 0.1);
    transition: transform 0.3s ease;
}

.gallery-item:hover {
    transform: scale(1.05);
}

.gallery-item img {
    width: 100%;
    height: 100%;
    object-fit: cover;
}

.placeholder-item {
    background: var(--gradient-primary);
    display: flex;
    align-items: center;
    justify-content: center;
}

.placeholder-content {
    text-align: center;
    color: var(--color-text-light);
}

.placeholder-content i {
    font-size: 3rem;
    margin-bottom: var(--spacing-sm);
    color: var(--color-primary);
}

.gallery-note {
    text-align: center;
    color: var(--color-text-light);
    font-size: 0.9rem;
    font-style: italic;
}

.gallery-note i {
    color: var(--color-primary);
}

/* ==========================================
   Thanks Section
   ========================================== */
.thanks-section {
    background: var(--gradient-overlay);
}

.thanks-card {
    max-width: 700px;
    margin: 0 auto;
    background: var(--color-white);
    padding: var(--spacing-xl);
    border-radius: 20px;
    box-shadow: 0 10px 40px rgba(0, 0, 0, 0.1);
    text-align: center;
}

.thanks-icon {
    font-size: 4rem;
    margin-bottom: var(--spacing-md);
}

.thanks-title {
    font-size: 2.5rem;
    color: var(--color-primary);
    margin-bottom: var(--spacing-md);
}

.thanks-message {
    font-size: 1.1rem;
    line-height: 2;
    color: var(--color-text);
    margin-bottom: var(--spacing-md);
}

.thanks-signature {
    font-family: var(--font-handwriting);
    font-size: 1.5rem;
    color: var(--color-text-light);
    margin-top: var(--spacing-md);
}

/* ==========================================
   Footer
   ========================================== */
.footer {
    background: linear-gradient(135deg, #D4AF37 0%, #A88B34 100%);
    color: var(--color-white);
    padding: var(--spacing-lg) 0;
    text-align: center;
}

.social-share {
    margin-bottom: var(--spacing-md);
}

.share-text {
    font-size: 1.1rem;
    margin-bottom: var(--spacing-sm);
}

.hashtag {
    font-family: var(--font-handwriting);
    font-size: 1.8rem;
    margin-bottom: var(--spacing-md);
    color: #FFF8E7;
}

.share-buttons {
    display: flex;
    justify-content: center;
    gap: var(--spacing-sm);
    margin-bottom: var(--spacing-md);
}

.share-btn {
    width: 50px;
    height: 50px;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    background: var(--color-white);
    color: var(--color-primary);
    text-decoration: none;
    transition: transform 0.3s ease, background-color 0.3s ease;
    font-size: 1.2rem;
}

.share-btn:hover {
    transform: translateY(-5px) scale(1.1);
}

.twitter-btn:hover {
    background: #1DA1F2;
    color: var(--color-white);
}

.facebook-btn:hover {
    background: #1877F2;
    color: var(--color-white);
}

.line-btn:hover {
    background: #00B900;
    color: var(--color-white);
}

.footer-decoration {
    font-size: 2rem;
    margin: var(--spacing-md) 0;
}

.copyright {
    font-size: 0.9rem;
    opacity: 0.9;
}

.copyright i {
    color: #FF6B6B;
    animation: heartBeat 1.5s ease-in-out infinite;
}

/* ==========================================
   BGM Toggle Button
   ========================================== */
.bgm-toggle {
    position: fixed;
    bottom: 30px;
    right: 30px;
    width: 60px;
    height: 60px;
    border-radius: 50%;
    background: var(--gradient-gold);
    border: none;
    color: var(--color-white);
    font-size: 1.5rem;
    cursor: pointer;
    box-shadow: 0 5px 20px rgba(212, 175, 55, 0.4);
    z-index: 1000;
    transition: transform 0.3s ease, box-shadow 0.3s ease;
}

.bgm-toggle:hover {
    transform: scale(1.1);
    box-shadow: 0 8px 30px rgba(212, 175, 55, 0.6);
}

.bgm-toggle.playing {
    animation: pulse 2s ease-in-out infinite;
}

/* ==========================================
   Animations
   ========================================== */
@keyframes fadeIn {
    from {
        opacity: 0;
    }
    to {
        opacity: 1;
    }
}

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

@keyframes slideInLeft {
    from {
        opacity: 0;
        transform: translateX(-50px);
    }
    to {
        opacity: 1;
        transform: translateX(0);
    }
}

@keyframes slideInRight {
    from {
        opacity: 0;
        transform: translateX(50px);
    }
    to {
        opacity: 1;
        transform: translateX(0);
    }
}

@keyframes bounceIn {
    0% {
        opacity: 0;
        transform: scale(0.3);
    }
    50% {
        transform: scale(1.05);
    }
    70% {
        transform: scale(0.9);
    }
    100% {
        opacity: 1;
        transform: scale(1);
    }
}

@keyframes bounce {
    0%, 100% {
        transform: translateY(0);
    }
    50% {
        transform: translateY(-10px);
    }
}

@keyframes float {
    0%, 100% {
        transform: translateY(0) rotate(0deg);
    }
    50% {
        transform: translateY(-20px) rotate(10deg);
    }
}

@keyframes twinkle {
    0%, 100% {
        opacity: 1;
        transform: scale(1);
    }
    50% {
        opacity: 0.5;
        transform: scale(0.8);
    }
}

@keyframes heartBeat {
    0%, 100% {
        transform: scale(1);
    }
    25% {
        transform: scale(1.2);
    }
    50% {
        transform: scale(1);
    }
}

@keyframes pulse {
    0%, 100% {
        transform: scale(1);
    }
    50% {
        transform: scale(1.05);
    }
}

/* ==========================================
   Utility Classes
   ========================================== */
.fade-in {
    animation: fadeInUp 0.8s ease-out both;
}

.fade-in:nth-child(1) { animation-delay: 0.1s; }
.fade-in:nth-child(2) { animation-delay: 0.2s; }
.fade-in:nth-child(3) { animation-delay: 0.3s; }
.fade-in:nth-child(4) { animation-delay: 0.4s; }
.fade-in:nth-child(5) { animation-delay: 0.5s; }

/* ==========================================
   Responsive Design
   ========================================== */
@media (max-width: 768px) {
    :root {
        --spacing-lg: 3rem;
        --spacing-xl: 4rem;
    }
    
    .hero-content {
        padding: var(--spacing-sm);
    }
    
    .reason-cards,
    .message-grid,
    .gallery-grid {
        grid-template-columns: 1fr;
    }
    
    .message-form-container {
        padding: var(--spacing-md);
    }
    
    .thanks-card {
        padding: var(--spacing-md);
    }
    
    .bgm-toggle {
        width: 50px;
        height: 50px;
        bottom: 20px;
        right: 20px;
        font-size: 1.2rem;
    }
    
    .balloon,
    .star {
        font-size: 2rem;
    }
}

@media (max-width: 480px) {
    .share-buttons {
        flex-wrap: wrap;
    }
    
    .section-title {
        font-size: 1.8rem;
    }
    
    .title-decoration {
        font-size: 1.2rem;
        margin: 0 var(--spacing-xs);
    }
}