@font-face {
    font-family: 'Noto Sans SC';
    src: url('../assets/fonts/noto-sans-sc-site.woff') format('woff');
    font-style: normal;
    font-weight: 100 900;
    font-display: swap;
}

@font-face {
    font-family: 'Boring Wind Display';
    src: url('../assets/fonts/smiley-sans-site.woff') format('woff');
    font-style: normal;
    font-weight: 400;
    font-display: swap;
}

/* ============================================
   1. Custom Properties
   ============================================ */

:root {
    /* Colors */
    --bg-color: #fffdf8;
    --text-main: #1a1a1a;
    --text-sub: #8e8e93;
    --line-color: #D49A2A;
    --footer-text: #aeaeb2;
    --footer-hover: #1a1a1a;
    --accent-color: #FF6B6B;
    --success-color: #FF6B6B;

    /* Components */
    --ctrl-bg: rgba(74, 45, 10, 0.045);
    --ctrl-border: rgba(118, 76, 18, 0.075);
    --ctrl-hover-bg: rgba(118, 76, 18, 0.09);
    --overlay-bg: rgba(38, 27, 12, 0.22);
    --modal-bg: rgba(255, 254, 250, 0.92);
    --modal-border: rgba(118, 76, 18, 0.12);
    --shadow-heavy: 0 24px 72px rgba(75, 48, 10, 0.16), 0 3px 12px rgba(75, 48, 10, 0.06);
    --email-bg: rgba(118, 76, 18, 0.045);
    --email-border: rgba(118, 76, 18, 0.1);
    --email-hover-bg: rgba(118, 76, 18, 0.075);
    --icon-hover-bg: rgba(0, 0, 0, 0.06);
    --modal-focus: rgba(255, 107, 107, 0.28);
    --logo-shadow: drop-shadow(0 8px 16px rgba(92, 56, 8, 0.075));
    --text-shadow-h1: 0 20px 40px rgba(132, 86, 18, 0.055);

    /* Typography */
    --font-sans: 'Noto Sans SC', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
    --font-email: 'Noto Sans SC', -apple-system, BlinkMacSystemFont, sans-serif;
    --font-brand: 'Boring Wind Display', 'Noto Sans SC', sans-serif;

    /* Sizing */
    --logo-size: 120px;

    /* Motion */
    --dur-slow: 0.8s;
    --dur-normal: 0.35s;

    /* Spacing */
    --space-md: 20px;
    --space-lg: 24px;
}

.dark-mode {
    --bg-color: #03040a;
    --text-main: #f7f8ff;
    --text-sub: #b7bdd4;
    --line-color: #7DD3FC;
    --footer-text: #858da8;
    --footer-hover: #f7f8ff;
    --success-color: #30d158;
    --ctrl-bg: rgba(247, 248, 255, 0.08);
    --ctrl-border: rgba(210, 224, 255, 0.12);
    --ctrl-hover-bg: rgba(210, 224, 255, 0.16);
    --overlay-bg: rgba(0, 0, 0, 0.5);
    --modal-bg: rgba(9, 11, 20, 0.9);
    --modal-border: rgba(210, 224, 255, 0.16);
    --shadow-heavy: 0 28px 88px rgba(0, 0, 0, 0.48), 0 3px 14px rgba(0, 0, 0, 0.24);
    --email-bg: rgba(210, 224, 255, 0.055);
    --email-border: rgba(210, 224, 255, 0.12);
    --email-hover-bg: rgba(210, 224, 255, 0.09);
    --icon-hover-bg: rgba(210, 224, 255, 0.12);
    --modal-focus: rgba(155, 188, 255, 0.3);
    --logo-shadow: drop-shadow(0 0 22px rgba(170, 205, 255, 0.28));
    --text-shadow-h1: 0 22px 46px rgba(90, 128, 255, 0.18);
}

/* ============================================
   2. Reset & Base
   ============================================ */

* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
    -webkit-tap-highlight-color: transparent;
}

body {
    background-color: var(--bg-color);
    color: var(--text-main);
    font-family: var(--font-sans);
    overflow: hidden;
    height: 100vh;
    height: 100dvh;
    width: 100%;
    display: flex;
    justify-content: center;
    align-items: center;
    user-select: none;
    cursor: none;
    overscroll-behavior: none;
    touch-action: none;
    transition: background-color var(--dur-slow) ease, color var(--dur-slow) ease;
}

body.modal-open { cursor: default }
body.modal-open .email-box,
body.modal-open .modal-close { cursor: pointer }
body::before {
    content: "";
    position: fixed;
    inset: 0;
    z-index: 0;
    pointer-events: none;
    background:
        radial-gradient(62% 52% at 50% 42%, rgba(255, 225, 150, 0.095), rgba(255, 255, 255, 0) 70%),
        radial-gradient(86% 70% at 50% 100%, rgba(255, 204, 120, 0.045), rgba(255, 255, 255, 0) 68%);
    opacity: 1;
    transition: opacity var(--dur-slow) ease;
}

.dark-mode body::before {
    opacity: 0;
}

a, button, .email-box, .slogan { cursor: pointer; touch-action: manipulation }
button { background: none; border: none; padding: 0; font: inherit; color: inherit; }

/* ============================================
   3. Canvas Layers
   ============================================ */

#bg-canvas, #trail-canvas {
    position: absolute;
    inset: 0;
    z-index: 0;
    width: 100%;
    height: 100%;
    display: block;
    pointer-events: none;
    contain: strict;
}

#trail-canvas {
    z-index: 1;
}

/* ============================================
   4. Top Controls
   ============================================ */

.top-bar {
    position: absolute;
    top: calc(var(--space-md) + env(safe-area-inset-top));
    right: calc(var(--space-md) + env(safe-area-inset-right));
    z-index: 100;
    display: flex;
    gap: 16px;
}

.ctrl-btn {
    width: 44px;
    height: 44px;
    border-radius: 50%;
    background: var(--ctrl-bg);
    border: 1px solid var(--ctrl-border);
    display: flex;
    align-items: center;
    justify-content: center;
    position: relative;
    transition: transform var(--dur-normal) cubic-bezier(0.25, 0.8, 0.25, 1), background var(--dur-normal);
    overflow: hidden;
}

.ctrl-btn:hover {
    transform: scale(1.1) rotate(15deg);
    background: var(--ctrl-hover-bg);
}

.lang-btn {
    font-size: 18px;
    font-weight: 600;
    letter-spacing: 0;
    color: var(--text-main);
    transition: transform var(--dur-normal) cubic-bezier(0.25, 0.8, 0.25, 1), background var(--dur-normal), color var(--dur-slow) ease;
}

.ctrl-icon {
    width: 22px;
    height: 22px;
    fill: none;
    stroke: var(--text-main);
    stroke-width: 2;
    stroke-linecap: round;
    stroke-linejoin: round;
    transition: stroke var(--dur-slow) ease;
}

/* ============================================
   5. Theme Icon Crossfade
   ============================================ */

.theme-icon {
    position: absolute;
    transition: opacity 0.4s ease, transform 0.4s ease;
}

#icon-moon { opacity: 1; transform: rotate(0deg) scale(1) }
#icon-sun  { opacity: 0; transform: rotate(-90deg) scale(0.5) }

.dark-mode #icon-moon { opacity: 0; transform: rotate(90deg) scale(0.5) }
.dark-mode #icon-sun  { opacity: 1; transform: rotate(0deg) scale(1) }

/* ============================================
   6. Modal
   ============================================ */

.modal-overlay {
    position: fixed;
    inset: 0;
    z-index: 1000;
    background: var(--overlay-bg);
    -webkit-backdrop-filter: blur(10px) saturate(110%);
    backdrop-filter: blur(10px) saturate(110%);
    display: flex;
    justify-content: center;
    align-items: center;
    padding:
        calc(18px + env(safe-area-inset-top))
        calc(18px + env(safe-area-inset-right))
        calc(18px + env(safe-area-inset-bottom))
        calc(18px + env(safe-area-inset-left));
    opacity: 0;
    pointer-events: none;
    transition: opacity 0.26s ease;
}

.modal-overlay.active {
    opacity: 1;
    pointer-events: auto;
}

.modal-box {
    position: relative;
    background: var(--modal-bg);
    border: 1px solid var(--modal-border);
    padding: 32px 30px 24px;
    border-radius: 8px;
    text-align: center;
    box-shadow: var(--shadow-heavy);
    opacity: 0;
    transform: translateY(14px) scale(0.975);
    transition:
        opacity 0.24s ease,
        transform 0.34s cubic-bezier(0.2, 0.8, 0.2, 1),
        background-color var(--dur-slow) ease,
        border-color var(--dur-slow) ease;
    width: min(408px, 100%);
    color: var(--text-main);
}

.modal-overlay.active .modal-box {
    opacity: 1;
    transform: scale(1) translateY(0);
}

.modal-close {
    position: absolute;
    top: 16px;
    right: 16px;
    width: 36px;
    height: 36px;
    border-radius: 50%;
    border: 1px solid transparent;
    display: flex;
    align-items: center;
    justify-content: center;
    transition: background 0.2s ease, border-color 0.2s ease, color 0.2s ease, transform 0.2s ease;
    color: var(--text-sub);
}

.modal-close:hover {
    background: var(--icon-hover-bg);
    border-color: var(--modal-border);
    color: var(--text-main);
}

.modal-close:active { transform: scale(0.92) }

.modal-close:focus-visible,
.email-box:focus-visible {
    outline: 3px solid var(--modal-focus);
    outline-offset: 2px;
}

.modal-close svg { width: 18px; height: 18px; stroke-width: 2.2 }

.modal-title {
    min-height: 36px;
    padding: 5px 44px 0;
    margin-bottom: 22px;
    font-size: 1.08rem;
    line-height: 1.45;
    font-weight: 650;
    letter-spacing: 0;
}

.email-box {
    background: var(--email-bg);
    min-height: 54px;
    padding: 15px 18px;
    border-radius: 6px;
    font-family: var(--font-email);
    font-weight: 500;
    font-size: 0.9rem;
    line-height: 1.45;
    letter-spacing: 0;
    display: flex;
    align-items: center;
    justify-content: center;
    overflow-wrap: anywhere;
    border: 1px solid var(--email-border);
    user-select: text;
    transition:
        transform 0.2s cubic-bezier(0.2, 0.8, 0.2, 1),
        background-color 0.2s ease,
        border-color 0.2s ease;
}

.email-box:hover {
    background: var(--email-hover-bg);
    border-color: var(--modal-border);
    transform: translateY(-1px);
}

.email-box:active { transform: translateY(0) scale(0.99) }

.copy-tip {
    font-size: 0.74rem;
    line-height: 1.5;
    letter-spacing: 0;
    color: var(--text-sub);
    margin-top: 12px;
    min-height: 1.5em;
    opacity: 0.78;
}

/* ============================================
   7. Content & Logo
   ============================================ */

.content {
    position: relative;
    z-index: 10;
    text-align: center;
    max-width: 90%;
    animation: fadeUp 1.5s cubic-bezier(0.2, 0.8, 0.2, 1) both;
    display: flex;
    flex-direction: column;
    align-items: center;
    transform-style: preserve-3d;
}

@keyframes fadeUp {
    from { opacity: 0; transform: scale(0.95) translateY(20px) }
    to { opacity: 1; transform: scale(1) translateY(0) }
}

.logo-wrap {
    position: relative;
    width: var(--logo-size);
    height: var(--logo-size);
    margin-bottom: 20px;
    transform: translateZ(30px);
}

.main-logo {
    width: var(--logo-size);
    height: auto;
    object-fit: contain;
    filter: var(--logo-shadow);
    transition: opacity 0.5s ease, filter var(--dur-slow) ease;
    position: absolute;
    top: 0;
    left: 0;
}

.logo-light { opacity: 0 }

.dark-mode #logo-dark  { opacity: 0 }
.dark-mode #logo-light { opacity: 1 }

.content h1 {
    font-family: var(--font-brand);
    font-size: 5.5rem;
    font-weight: 400;
    letter-spacing: 0;
    line-height: 1;
    margin-bottom: 1.5rem;
    color: var(--text-main);
    text-shadow: var(--text-shadow-h1);
    transform: translateZ(20px);
    transition: color var(--dur-slow) ease;
}

.slogan {
    font-family: var(--font-brand);
    font-size: 1.6rem;
    color: var(--text-main);
    font-weight: 400;
    letter-spacing: 0;
    margin-top: 1rem;
    display: inline-block;
    position: relative;
    padding-bottom: 4px;
    transform: translateZ(10px);
    transition: color var(--dur-slow) ease;
}

.slogan::after {
    content: "";
    position: absolute;
    bottom: -2px;
    left: 0;
    width: 100%;
    height: 2px;
    background: var(--line-color);
    border-radius: 2px;
    transform: scaleX(0);
    transform-origin: center;
    transition: transform 0.3s cubic-bezier(0.25, 0.46, 0.45, 0.94), background var(--dur-slow) ease;
}

.slogan:hover::after { transform: scaleX(1) }

/* ============================================
   8. Footer
   ============================================ */

body > footer {
    position: absolute;
    bottom: calc(var(--space-lg) + env(safe-area-inset-bottom));
    width: 100%;
    text-align: center;
    z-index: 10;
    display: flex;
    flex-wrap: wrap;
    gap: 15px;
    align-items: center;
    justify-content: center;
    padding: 0 var(--space-md);
    transition: color var(--dur-slow) ease;
}

html:not(.dark-mode) body > footer { mix-blend-mode: multiply }

.ft {
    font-size: 12px;
    color: var(--footer-text);
    text-decoration: none;
    display: flex;
    align-items: center;
    gap: 6px;
    transition: color var(--dur-slow) ease;
    white-space: nowrap;
}

.ft:hover { color: var(--footer-hover) }

.ft-icon {
    width: 14px;
    height: 14px;
    vertical-align: -2px;
    object-fit: contain;
}

/* ============================================
   9. Responsive
   ============================================ */

@media (max-width: 768px) {
    .modal-overlay {
        -webkit-backdrop-filter: blur(7px) saturate(108%);
        backdrop-filter: blur(7px) saturate(108%);
    }

    .content {
        max-width: min(88%, 560px);
        margin-bottom: 34px;
    }

    .content h1 {
        font-size: clamp(2.65rem, 12vw, 3.6rem);
        letter-spacing: 0;
    }

    .slogan {
        font-size: clamp(1rem, 4.2vw, 1.15rem);
        max-width: 86%;
        line-height: 1.55;
        letter-spacing: 0;
    }

    body > footer {
        gap: 8px 12px;
        bottom: calc(14px + env(safe-area-inset-bottom));
        padding: 0 calc(16px + env(safe-area-inset-left)) 0 calc(16px + env(safe-area-inset-right));
    }

    .ft { font-size: 11px }
    .logo-wrap { --logo-size: 88px }
    .main-logo { width: var(--logo-size) }
    .modal-box { padding: 30px 24px 22px }
}

@media (max-width: 480px) {
    .content {
        max-width: 92%;
        margin-bottom: 58px;
    }

    .content h1 {
        font-size: clamp(2.25rem, 13vw, 2.8rem);
        letter-spacing: 0;
    }

    .slogan {
        font-size: clamp(0.92rem, 4.4vw, 1rem);
        letter-spacing: 0;
        max-width: 92%;
    }

    .logo-wrap { --logo-size: 72px }
    .main-logo { width: var(--logo-size) }

    body > footer {
        flex-direction: column;
        gap: 5px;
        bottom: calc(10px + env(safe-area-inset-bottom));
    }

    .top-bar {
        top: calc(10px + env(safe-area-inset-top));
        right: calc(10px + env(safe-area-inset-right));
        gap: 8px;
    }

    .ctrl-btn { width: 44px; height: 44px }
    .ctrl-icon { width: 19px; height: 19px }

    .modal-overlay {
        padding:
            calc(12px + env(safe-area-inset-top))
            calc(12px + env(safe-area-inset-right))
            calc(12px + env(safe-area-inset-bottom))
            calc(12px + env(safe-area-inset-left));
    }

    .modal-box { padding: 26px 18px 20px }
    .modal-title { margin-bottom: 18px }
    .email-box { padding: 14px 10px; font-size: 0.82rem }
}

@media (max-height: 620px) and (max-width: 768px) {
    .content { margin-bottom: 82px }
    .logo-wrap { --logo-size: 58px; margin-bottom: 12px }
    .content h1 { font-size: clamp(2rem, 10vw, 2.5rem); margin-bottom: 0.9rem }
    .slogan { margin-top: 0.4rem }
    body > footer { display: none }
}

@media (pointer: coarse) {
    body { cursor: default }
    .ctrl-btn:hover { transform: none }
    .slogan:hover::after { transform: scaleX(0) }
    .email-box:hover { transform: none }
}

/* ============================================
   10. Accessibility
   ============================================ */

@media (prefers-reduced-motion: reduce) {
    * {
        animation-duration: 0s !important;
        transition-duration: 0s !important;
    }
}