/* ==========================================
   StudyManage LP — Main Stylesheet
   ========================================== */

/* Base */
html {
    scroll-behavior: smooth;
    overflow-x: hidden;
}
body {
    font-family: 'Inter', 'Noto Sans JP', sans-serif;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
    letter-spacing: -0.01em;
    overflow-x: hidden;
}
.safe-bottom {
    padding-bottom: env(safe-area-inset-bottom, 0);
}

/* Glassmorphism */
.glass {
    background: rgba(255,255,255,0.72);
    backdrop-filter: blur(20px);
    -webkit-backdrop-filter: blur(20px);
    border: 1px solid rgba(255,255,255,0.5);
    box-shadow: 0 8px 32px rgba(0,0,0,0.06);
}
.glass-subtle {
    background: rgba(255,255,255,0.5);
    backdrop-filter: blur(12px);
    -webkit-backdrop-filter: blur(12px);
    border: 1px solid rgba(255,255,255,0.3);
}

/* Hover lift for cards */
.hover-lift {
    transition: transform 0.3s cubic-bezier(0.34,1.56,0.64,1), box-shadow 0.3s ease;
}
.hover-lift:hover {
    transform: translateY(-4px) scale(1.02);
    box-shadow: 0 16px 48px rgba(0,0,0,0.1);
}

/* Scale press for buttons */
.btn-press {
    transition: transform 0.2s ease, box-shadow 0.2s ease, background 0.2s ease;
}
.btn-press:hover {
    transform: scale(1.02);
}
.btn-press:active {
    transform: scale(0.975);
}

/* Fade-in on scroll */
.fade-in {
    opacity: 0;
    transform: translateY(24px);
    transition: opacity 0.7s cubic-bezier(0.16,1,0.3,1), transform 0.7s cubic-bezier(0.16,1,0.3,1);
}
.fade-in.visible {
    opacity: 1;
    transform: translateY(0);
}
.fade-in-delay-1 { transition-delay: 0.1s; }
.fade-in-delay-2 { transition-delay: 0.2s; }
.fade-in-delay-3 { transition-delay: 0.3s; }

/* Subtle gradient background mesh */
.bg-mesh {
    background-image:
        radial-gradient(at 20% 20%, rgba(37,99,235,0.06) 0, transparent 50%),
        radial-gradient(at 80% 80%, rgba(139,92,246,0.05) 0, transparent 50%),
        radial-gradient(at 50% 50%, rgba(37,99,235,0.03) 0, transparent 70%);
}

/* Section divider gradient */
.section-divider {
    height: 1px;
    background: linear-gradient(90deg, transparent, rgba(37,99,235,0.12), transparent);
}

/* Heading styles */
h1, h2, h3 {
    letter-spacing: -0.025em;
}

/* Smooth transitions on interactive elements */
a, button, input {
    transition-property: color, background-color, border-color, box-shadow, transform, opacity;
    transition-duration: 0.2s;
    transition-timing-function: ease;
}

/* Off-screen section rendering optimization */
section:not(:first-child) {
    content-visibility: auto;
    contain-intrinsic-size: auto 800px;
}