/* ==================== */
/* Variables & Reset */
/* ==================== */
:root {
    --primary-color: #1a2a3a;
    --secondary-color: #2c3e50;
    --accent-color: #3498db;
    --dark-color: #1a1a1a;
    --light-color: #f0f4f8;
    --text-color: #2c3e50;
    --text-muted: #7f8c8d;
    --card-shadow: 0 2px 8px rgba(0, 0, 0, 0.08);
    --card-shadow-hover: 0 4px 16px rgba(0, 0, 0, 0.12);
    --transition: all 0.2s ease;
}

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

html {
    scroll-behavior: smooth;
}

body {
    font-family: "Noto Sans JP", sans-serif;
    line-height: 1.7;
    color: var(--text-color);
    background-color: #f8f9fa;
    overflow-x: hidden;
    transition: background-color 0.3s ease, color 0.3s ease;
}

/* ==================== */
/* Dark Mode Color Calculations */
/* ==================== */
/* Light Mode Base Colors:
   - Background: #f8f9fa (248, 249, 250) → ratio to white ≈ 0.97
   - Cards: #ffffff (255, 255, 255) → ratio 1.0
   - Section BG: #f0f4f8 (240, 244, 248) → ratio ≈ 0.94
   - Text: #2c3e50 (44, 62, 80) → ratio ≈ 0.24
   - Text Muted: #7f8c8d (127, 140, 141) → ratio ≈ 0.50

   Dark Mode Formula: darkValue = 255 - (lightValue × ratio)
*/

body.dark-mode {
    background-color: #0a0a0a;
    color: #c4c4c4;
}

body.dark-mode .navbar {
    background: #101010 !important;
    box-shadow: 0 2px 8px rgba(0, 0, 0, 0.3);
}

body.dark-mode .section-padding {
    background-color: #0a0a0a;
}

body.dark-mode .section-padding.bg-light {
    background-color: #0a0a0a;
}

body.dark-mode .info-card,
body.dark-mode .profile-text-card,
body.dark-mode .article-card,
body.dark-mode .timeline-content {
    background: #141414;
    color: #c4c4c4;
    border-color: #2a2a2a;
}

body.dark-mode .info-icon {
    background: #1a1a1a;
}

body.dark-mode .article-source {
    background: #0066cc;
}

body.dark-mode .skill-tag {
    background: #1a1a1a;
    color: #c4c4c4;
    border-color: #2a2a2a;
}

body.dark-mode .skill-tag:hover {
    background: var(--accent-color);
    color: white;
}

body.dark-mode .section-title,
body.dark-mode .category-title,
body.dark-mode h4,
body.dark-mode .timeline-date {
    color: #c4c4c4;
}

body.dark-mode .text-muted {
    color: #808080 !important;
}

body.dark-mode .hero-section {
    background: linear-gradient(135deg, #0a0a0a 0%, #141414 100%);
}

body.dark-mode .hero-content {
    color: #c4c4c4;
}

body.dark-mode .hero-title {
    color: #c4c4c4;
}

body.dark-mode .hero-subtitle {
    color: #808080;
}

body.dark-mode .scroll-indicator a {
    color: #c4c4c4 !important;
}

body.dark-mode .category-title {
    color: #c4c4c4;
    border-bottom-color: #2a2a2a;
}

body.dark-mode .timeline::before {
    background: #2a2a2a;
}

body.dark-mode .timeline-date {
    color: #64b5f6;
}

body.dark-mode .timeline-content {
    border-left-color: #64b5f6;
}

body.dark-mode .article-header {
    color: #c4c4c4;
}

body.dark-mode .article-date {
    color: #64b5f6;
}

body.dark-mode .article-title {
    color: #c4c4c4;
}

body.dark-mode .article-tag {
    background: #1a1a1a;
    color: #808080;
}

body.dark-mode .footer {
    background: linear-gradient(135deg, #0a0a0a 0%, #141414 100%);
}

body.dark-mode a {
    color: #64b5f6;
}

body.dark-mode a:hover {
    color: #90caf9;
}

body.dark-mode .btn-outline-primary {
    color: #64b5f6;
    border-color: #64b5f6;
}

body.dark-mode .btn-outline-primary:hover {
    background-color: #64b5f6;
    border-color: #64b5f6;
    color: #0a0a0a;
}

body.dark-mode .skill-group-title {
    color: #c4c4c4;
    border-bottom-color: #2a2a2a;
}

body.dark-mode .profile-intro {
    color: #c4c4c4;
}

body.dark-mode .profile-intro a {
    color: #64b5f6;
}

body.dark-mode .profile-intro a:hover {
    color: #90caf9;
}

body.dark-mode .profile-bonus {
    background: linear-gradient(135deg, #1a3a4a 0%, #153a47 100%);
    border-left-color: #64b5f6;
}

body.dark-mode .navbar-brand {
    color: #c4c4c4 !important;
}

body.dark-mode .navbar-nav .nav-link {
    color: #808080 !important;
}

body.dark-mode .navbar-nav .nav-link:hover {
    color: #64b5f6 !important;
}

body.dark-mode #darkModeToggle,
body.dark-mode #languageToggle {
    color: #e0e0e0 !important;
    border-color: #555555 !important;
}

body.dark-mode #darkModeToggle:hover,
body.dark-mode #languageToggle:hover {
    color: #64b5f6 !important;
    border-color: #64b5f6 !important;
    background-color: rgba(100, 181, 246, 0.1);
}

/* ==================== */
/* Navbar */
/* ==================== */
.navbar {
    background: #f5f5f5;
    padding: 1rem 0;
    box-shadow: 0 2px 8px rgba(0, 0, 0, 0.08);
    transition: var(--transition);
}

.navbar-brand {
    font-size: 1.5rem;
    font-weight: 700;
    letter-spacing: 1px;
    color: var(--primary-color) !important;
}

#darkModeToggle,
#languageToggle {
    color: #2c3e50 !important;
    border-color: #bdc3c7 !important;
    padding: 0.4rem 0.8rem !important;
    font-weight: 500;
}

#darkModeToggle:hover,
#languageToggle:hover {
    color: #3498db !important;
    border-color: #3498db !important;
    background-color: rgba(52, 152, 219, 0.05);
}

.navbar-nav .nav-link {
    color: var(--text-muted) !important;
    font-weight: 500;
    margin: 0 0.5rem;
    padding: 0.5rem 1rem !important;
    border-radius: 4px;
    transition: var(--transition);
}

.navbar-nav .nav-link:hover {
    background-color: transparent;
    color: var(--accent-color) !important;
}

/* Hamburger Menu */
.navbar-toggler {
    border-color: #bdc3c7 !important;
    padding: 0.4rem 0.8rem !important;
}

.navbar-toggler:focus {
    box-shadow: none;
    border-color: #3498db !important;
}

.navbar-toggler-icon {
    background-image: url("data:image/svg+xml,%3csvg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 30 30'%3e%3cpath stroke='%232c3e50' stroke-linecap='round' stroke-miterlimit='10' stroke-width='2.5' d='M4 7h22M4 15h22M4 23h22'/%3e%3c/svg%3e");
}

body.dark-mode .navbar-toggler {
    border-color: #555555 !important;
}

body.dark-mode .navbar-toggler:focus {
    border-color: #64b5f6 !important;
}

body.dark-mode .navbar-toggler-icon {
    background-image: url("data:image/svg+xml,%3csvg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 30 30'%3e%3cpath stroke='%23e0e0e0' stroke-linecap='round' stroke-miterlimit='10' stroke-width='2.5' d='M4 7h22M4 15h22M4 23h22'/%3e%3c/svg%3e");
}

/* Dark Mode & Language Toggle */
#darkModeToggle {
    color: var(--text-muted) !important;
    border-color: var(--text-muted) !important;
    padding: 0.4rem 0.8rem !important;
    font-size: 1.1rem;
    transition: var(--transition);
}

#darkModeToggle:hover {
    color: var(--accent-color) !important;
    border-color: var(--accent-color) !important;
}


/* ==================== */
/* Hero Section */
/* ==================== */
.hero-section {
    min-height: 100vh;
    display: flex;
    align-items: center;
    justify-content: center;
    background: linear-gradient(135deg, #f8f9fa 0%, #eef2f5 100%);
    position: relative;
    overflow: hidden;
    padding-top: 80px;
}

.hero-section::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: transparent;
    pointer-events: none;
}

.hero-content {
    text-align: center;
    color: var(--dark-color);
    z-index: 1;
}

.profile-image {
    width: 280px;
    height: 280px;
    border-radius: 50%;
    border: none;
    box-shadow: 0 8px 24px rgba(0, 0, 0, 0.1);
    object-fit: cover;
    transition: var(--transition);
}

.profile-image:hover {
    transform: scale(1.02);
    box-shadow: 0 12px 32px rgba(0, 0, 0, 0.12);
}

.hero-title {
    font-size: 3.5rem;
    font-weight: 700;
    margin-bottom: 1rem;
    text-shadow: 2px 2px 4px rgba(0, 0, 0, 0.2);
    font-family: "Noto Serif JP", serif;
}

.hero-subtitle {
    font-size: 1.5rem;
    font-weight: 300;
    opacity: 0.8;
    color: var(--text-muted);
}

.social-links {
    display: flex;
    gap: 1.5rem;
    justify-content: center;
    flex-wrap: wrap;
}

.social-icon {
    width: 60px;
    height: 60px;
    display: flex;
    align-items: center;
    justify-content: center;
    background: rgba(255, 255, 255, 0.2);
    border-radius: 50%;
    color: white;
    font-size: 1.8rem;
    transition: var(--transition);
    backdrop-filter: blur(10px);
}

.social-icon:hover {
    background: rgba(255, 255, 255, 0.3);
    transform: translateY(-5px) scale(1.1);
    color: white;
}

/* ==================== */
/* Section Styles */
/* ==================== */
.section-padding {
    padding: 100px 0;
}

.section-title {
    font-size: 2.5rem;
    font-weight: 700;
    position: relative;
    display: inline-block;
    font-family: "Noto Serif JP", serif;
}

.section-title::after {
    content: '';
    position: absolute;
    bottom: -10px;
    left: 50%;
    transform: translateX(-50%);
    width: 60px;
    height: 3px;
    background: var(--accent-color);
    border-radius: 2px;
}

/* ==================== */
/* Info Cards */
/* ==================== */
.info-card {
    background: white;
    padding: 2rem;
    border-radius: 8px;
    box-shadow: var(--card-shadow);
    transition: var(--transition);
    height: 100%;
    border: 1px solid #e8ecf1;
}

.info-card:hover {
    transform: translateY(-2px);
    box-shadow: var(--card-shadow-hover);
}

.info-icon {
    width: 60px;
    height: 60px;
    background: #f0f4f8;
    border-radius: 8px;
    display: flex;
    align-items: center;
    justify-content: center;
    color: var(--accent-color);
    font-size: 1.8rem;
    margin-bottom: 1rem;
}

.info-card h4 {
    font-size: 1.2rem;
    font-weight: 600;
    color: var(--dark-color);
    margin-bottom: 0.5rem;
}

.info-card p, .info-card ul {
    color: var(--text-muted);
    margin: 0;
}

.info-card ul {
    padding-left: 1.2rem;
}

/* ==================== */
/* Profile Text Card */
/* ==================== */
.profile-text-card {
    background: white;
    padding: 2.5rem;
    border-radius: 8px;
    box-shadow: var(--card-shadow);
    border: 1px solid #e8ecf1;
    max-width: none;
}

.profile-intro {
    font-size: 1rem;
    line-height: 1.8;
    color: var(--text-color);
    margin-bottom: 0.8rem;
}

.profile-intro:last-child {
    margin-bottom: 0;
}

.profile-bonus {
    background: linear-gradient(135deg, #e8f4f8 0%, #f0f8fa 100%);
    border-left: 4px solid var(--accent-color);
    padding: 1.2rem;
    border-radius: 6px;
    margin-top: 1.5rem;
    font-weight: 500;
}

/* ==================== */
/* Timeline */
/* ==================== */
.category-title {
    font-size: 1.8rem;
    font-weight: 600;
    color: var(--dark-color);
    display: flex;
    align-items: center;
    padding: 1rem 0;
    border-bottom: 2px solid #e2e8f0;
}

.timeline {
    position: relative;
    padding-left: 2rem;
    margin: 2rem 0;
}

.timeline::before {
    content: '';
    position: absolute;
    left: 0;
    top: 0;
    bottom: 0;
    width: 2px;
    background: #e8ecf1;
    border-radius: 2px;
}

.timeline-item {
    position: relative;
    padding-left: 2rem;
    margin-bottom: 2.5rem;
}

.timeline-marker {
    display: none;
}

.timeline-content {
    background: white;
    padding: 1.5rem;
    border-radius: 8px;
    box-shadow: var(--card-shadow);
    transition: var(--transition);
    border-left: 3px solid var(--accent-color);
}

.timeline-content:hover {
    transform: translateX(2px);
    box-shadow: var(--card-shadow-hover);
}

.timeline-date {
    color: var(--primary-color);
    font-weight: 600;
    font-size: 0.9rem;
    margin-bottom: 0.5rem;
}

.timeline-content h4 {
    font-size: 1.3rem;
    font-weight: 600;
    color: var(--dark-color);
    margin-bottom: 0.5rem;
}

.timeline-content p {
    color: var(--text-muted);
    margin-bottom: 1rem;
}

.tech-tags {
    display: flex;
    flex-wrap: wrap;
    gap: 0.5rem;
    margin-bottom: 1rem;
}

.tech-tags .badge {
    padding: 0.4rem 0.8rem;
    font-size: 0.85rem;
    font-weight: 500;
}

/* ==================== */
/* Skills Section */
/* ==================== */
.skill-group {
    margin-bottom: 2rem;
}

.skill-group-title {
    font-size: 1.2rem;
    font-weight: 600;
    color: var(--dark-color);
    margin-bottom: 1rem;
    padding-bottom: 0.8rem;
    border-bottom: 2px solid #e2e8f0;
}

.skills-container {
    display: flex;
    flex-wrap: wrap;
    gap: 0.6rem;
}

.skill-tag {
    display: inline-block;
    padding: 0.6rem 1.2rem;
    background: white;
    color: var(--text-color);
    border: 1px solid #d0d8e0;
    border-radius: 20px;
    font-size: 0.95rem;
    font-weight: 500;
    transition: var(--transition);
    cursor: default;
}

.skill-tag:hover {
    background: var(--accent-color);
    color: white;
    border-color: var(--accent-color);
    transform: translateY(-2px);
    box-shadow: 0 4px 12px rgba(52, 152, 219, 0.2);
}

/* ==================== */
/* Article Card */
/* ==================== */
.article-card {
    background: white;
    padding: 1.5rem;
    border-radius: 8px;
    box-shadow: var(--card-shadow);
    transition: var(--transition);
    height: 100%;
    display: flex;
    flex-direction: column;
    border: 1px solid #e8ecf1;
}

.article-card:hover {
    transform: translateY(-4px);
    box-shadow: var(--card-shadow-hover);
}

.article-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 0.5rem;
}

.article-source {
    display: inline-block;
    padding: 0.3rem 0.8rem;
    background: var(--accent-color);
    color: white;
    border-radius: 4px;
    font-size: 0.75rem;
    font-weight: 600;
}

.article-likes {
    display: flex;
    align-items: center;
    gap: 0.3rem;
    color: var(--accent-color);
    font-size: 0.85rem;
    font-weight: 600;
}

.article-date {
    color: var(--accent-color);
    font-size: 0.85rem;
    font-weight: 600;
    margin-bottom: 0.5rem;
}

.article-title {
    font-size: 1.1rem;
    font-weight: 600;
    color: var(--dark-color);
    margin-bottom: 1rem;
    flex-grow: 1;
    line-height: 1.4;
}

.article-tags {
    display: flex;
    flex-wrap: wrap;
    gap: 0.4rem;
    margin-bottom: 1rem;
}

.article-tag {
    display: inline-block;
    padding: 0.3rem 0.6rem;
    background: #f0f4f8;
    color: var(--text-muted);
    border-radius: 4px;
    font-size: 0.75rem;
    font-weight: 500;
}

/* ==================== */
/* Back to Top Button */
/* ==================== */
#myBtn {
    display: none;
    position: fixed;
    bottom: 30px;
    right: 30px;
    z-index: 99;
    border: none;
    outline: none;
    background: linear-gradient(135deg, var(--primary-color), var(--secondary-color));
    color: white;
    cursor: pointer;
    padding: 15px;
    border-radius: 50%;
    font-size: 1.2rem;
    width: 60px;
    height: 60px;
    box-shadow: 0 4px 20px rgba(102, 126, 234, 0.4);
    transition: var(--transition);
}

#myBtn:hover {
    transform: translateY(-5px);
    box-shadow: 0 6px 25px rgba(102, 126, 234, 0.6);
}

/* ==================== */
/* Footer */
/* ==================== */
.footer {
    background: linear-gradient(135deg, var(--primary-color) 0%, var(--secondary-color) 100%);
    color: white;
    padding: 2rem 0;
    margin-top: 4rem;
}

/* ==================== */
/* Animations */
/* ==================== */
@keyframes fadeInUp {
    from {
        opacity: 0;
        transform: translateY(10px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

@keyframes fadeInLeft {
    from {
        opacity: 0;
        transform: translateX(-10px);
    }
    to {
        opacity: 1;
        transform: translateX(0);
    }
}

/* ==================== */
/* Scroll Indicator */
/* ==================== */
.scroll-indicator {
    animation: bounce 2s infinite;
}

.scroll-indicator a {
    color: var(--primary-color) !important;
}

.scroll-indicator i {
    filter: drop-shadow(0 2px 4px rgba(0, 0, 0, 0.2));
}

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

/* ==================== */
/* Responsive Design */
/* ==================== */
@media (max-width: 768px) {
    .hero-title {
        font-size: 2.5rem;
    }

    .hero-subtitle {
        font-size: 1.2rem;
    }

    .profile-image {
        width: 200px;
        height: 200px;
    }

    .section-title {
        font-size: 2rem;
    }

    .section-padding {
        padding: 60px 0;
    }

    .timeline {
        padding-left: 0;
    }

    .timeline::before {
        display: none;
    }

    .timeline-item {
        padding-left: 0;
        margin-bottom: 1.5rem;
    }

    .timeline-marker {
        display: none;
    }

    #myBtn {
        width: 50px;
        height: 50px;
        bottom: 20px;
        right: 20px;
        padding: 10px;
    }
}

@media (max-width: 576px) {
    .hero-title {
        font-size: 2rem;
    }

    .hero-subtitle {
        font-size: 1rem;
    }

    .social-icon {
        width: 50px;
        height: 50px;
        font-size: 1.5rem;
    }

    .navbar-brand {
        font-size: 1.2rem;
    }
}