/* ========================================
   Global Styles for AI Agent Book Site
   ======================================== */

:root {
    --navy: #0a1628;
    --navy-light: #1a2744;
    --cyan: #00d9ff;
    --cyan-dark: #0099cc;
    --warm-white: #f5f1e8;
    --gray: #8892a6;
}

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

body {
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "Noto Sans JP", "Hiragino Sans", "Hiragino Kaku Gothic ProN", "Yu Gothic", "游ゴシック体", "Meiryo", sans-serif;
    background: var(--warm-white);
    color: var(--navy);
    line-height: 1.7;
    overflow-x: hidden;
}

.mono {
    font-family: 'JetBrains Mono', monospace;
}

/* ========================================
   Header
   ======================================== */

.site-header {
    background: var(--navy);
    color: var(--warm-white);
    padding: 3rem 2rem;
    position: relative;
    overflow: hidden;
}

.site-header::before {
    content: '';
    position: absolute;
    top: -50%;
    right: -20%;
    width: 100%;
    height: 200%;
    background: linear-gradient(135deg, var(--cyan) 0%, transparent 70%);
    opacity: 0.03;
    transform: rotate(-12deg);
}

.header-content {
    max-width: 1200px;
    margin: 0 auto;
    position: relative;
    z-index: 2;
}

.back-link {
    display: inline-block;
    color: var(--cyan);
    text-decoration: none;
    font-size: 0.9rem;
    margin-bottom: 1rem;
    transition: color 0.3s;
}

.back-link:hover {
    color: var(--warm-white);
}

.page-title {
    font-size: clamp(2rem, 6vw, 3.5rem);
    font-weight: 700;
    margin-bottom: 0.5rem;
}

.page-subtitle {
    color: var(--gray);
    font-size: clamp(1rem, 2.5vw, 1.3rem);
}

/* ========================================
   Main Container
   ======================================== */

.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 4rem 2rem;
}

/* ========================================
   Section Headers
   ======================================== */

.section-label {
    font-size: 0.75rem;
    letter-spacing: 0.3em;
    text-transform: uppercase;
    color: var(--cyan-dark);
    margin-bottom: 1rem;
    font-weight: 700;
}

.section-title {
    font-size: clamp(1.8rem, 4vw, 2.5rem);
    font-weight: 700;
    margin-bottom: 1.5rem;
    color: var(--navy);
}

/* ========================================
   Cards
   ======================================== */

.card {
    background: white;
    padding: 3rem 2rem;
    border-radius: 16px;
    border-left: 3px solid var(--navy);
    position: relative;
}

.card::before {
    content: '';
    position: absolute;
    top: 0;
    right: 0;
    width: 60px;
    height: 60px;
    background: var(--cyan);
    opacity: 0.05;
    clip-path: polygon(100% 0, 100% 100%, 0 0);
}

.text-center {
    text-align: center;
}

/* ========================================
   Buttons
   ======================================== */

.btn {
    padding: 1rem 2.5rem;
    font-size: 1rem;
    font-weight: 600;
    text-decoration: none;
    border: none;
    cursor: pointer;
    transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
    position: relative;
    overflow: hidden;
    display: inline-block;
}

.btn-primary {
    background: var(--cyan);
    color: var(--navy);
    border-radius: 12px;
}

.btn-primary::before {
    content: '';
    position: absolute;
    inset: 0;
    background: linear-gradient(135deg, rgba(255,255,255,0.3), transparent);
    opacity: 0;
    transition: opacity 0.3s;
}

.btn-primary:hover::before {
    opacity: 1;
}

.btn-primary:hover {
    transform: translateY(-2px);
    box-shadow: 0 10px 30px rgba(0, 217, 255, 0.3);
}

.btn-secondary {
    background: transparent;
    color: var(--navy);
    border: 2px solid var(--navy);
    border-radius: 12px;
}

.btn-secondary:hover {
    background: var(--navy);
    color: var(--warm-white);
    transform: translateY(-2px);
}

/* ========================================
   Forms
   ======================================== */

.form-label {
    display: block;
    font-weight: 600;
    color: var(--navy);
    margin-bottom: 0.5rem;
    font-size: 0.95rem;
}

.form-input,
.form-select,
.form-textarea {
    width: 100%;
    padding: 0.875rem 1rem;
    font-size: 1rem;
    font-family: inherit;
    border: 2px solid #e5e7eb;
    background: white;
    color: var(--navy);
    transition: all 0.3s;
    border-radius: 10px;
}

.form-input:focus,
.form-select:focus,
.form-textarea:focus {
    outline: none;
    border-color: var(--cyan);
    box-shadow: 0 0 0 3px rgba(0, 217, 255, 0.1);
}

.form-textarea {
    resize: vertical;
    min-height: 120px;
    line-height: 1.6;
}

/* ========================================
   Footer
   ======================================== */

footer {
    background: var(--navy);
    color: var(--gray);
    padding: 3rem 2rem;
    text-align: center;
    border-top: 1px solid var(--navy-light);
}

footer a {
    color: var(--cyan);
    text-decoration: none;
    transition: color 0.3s;
}

footer a:hover {
    color: var(--warm-white);
}

/* ========================================
   Responsive
   ======================================== */

@media (max-width: 768px) {
    .container {
        padding: 3rem 1.5rem;
    }

    .site-header {
        padding: 2rem 1.5rem;
    }

    .card {
        padding: 2rem 1.5rem;
    }

    .btn {
        width: 100%;
        text-align: center;
    }
}

@media (max-width: 480px) {
    .container {
        padding: 2rem 1rem;
    }

    .site-header {
        padding: 1.5rem 1rem;
    }
}