/* Custom App Palette & Reset */
:root {
    --bg-app: #e0f2fe;         /* Soft, comforting pastel sky blue */
    --card-bg: #ffffff;        /* Pure white for clean content panels */
    --accent-blue: #38bdf8;    /* Cheerful mid-tone pastel blue for primary buttons */
    --accent-hover: #0ea5e9;   /* Slightly deeper blue for button hover effects */
    --text-dark: #0f172a;      /* Dark slate for readable headings */
    --text-sub: #475569;       /* Soft charcoal for secondary text details */
}

* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
    font-family: 'Inter', system-ui, -apple-system, sans-serif;
}

body {
    background-color: var(--bg-app);
    color: var(--text-dark);
    padding: 30px 16px;
    min-height: 100vh;
}

/* Friendly App Header */
header {
    text-align: center;
    margin-bottom: 35px;
}

header h1 {
    font-size: 2.2rem;
    font-weight: 800;
    color: #0369a1; /* Deep ocean blue for a punchy, friendly title */
    margin-bottom: 6px;
    letter-spacing: -0.02em;
}

header p {
    color: var(--text-sub);
    font-size: 0.95rem;
    font-weight: 500;
}

/* Casual Upload Interface Card */
.upload-container {
    max-width: 500px;
    margin: 0 auto 40px auto;
    background: var(--card-bg);
    padding: 20px;
    border-radius: 20px; /* Generous rounding for a friendly, app-like appearance */
    box-shadow: 0 8px 20px rgba(14, 165, 233, 0.1); /* Soft, colored drop shadow */
    display: flex;
    gap: 12px;
    align-items: center;
}

/* Customized Web File Input Component */
#photo-input {
    flex-grow: 1;
    color: var(--text-sub);
    font-size: 0.85rem;
}

#photo-input::file-selector-button {
    background: #f0f9ff;
    color: #0369a1;
    border: 1px solid #bae6fd;
    padding: 8px 14px;
    border-radius: 12px;
    cursor: pointer;
    font-weight: 600;
    margin-right: 8px;
    transition: all 0.2s ease;
}

#photo-input::file-selector-button:hover {
    background: #e0f2fe;
}

/* Rounded Upload Execution Button */
#upload-btn {
    background-color: var(--accent-blue);
    color: white;
    border: none;
    padding: 10px 20px;
    border-radius: 14px;
    cursor: pointer;
    font-weight: 700;
    font-size: 0.9rem;
    transition: all 0.2s ease;
    box-shadow: 0 4px 10px rgba(56, 189, 248, 0.3);
}

#upload-btn:hover {
    background-color: var(--accent-hover);
    transform: translateY(-1px);
}

/* Dynamic Photo Grid Feed */
.gallery-container {
    max-width: 1100px;
    margin: 0 auto;
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(260px, 1fr));
    gap: 20px;
}

/* Cozy Photo Card Treatments */
.gallery-container img {
    width: 100%;
    height: 280px;
    object-fit: cover;
    border-radius: 18px; /* Smooth rounded images match the interface card */
    background-color: var(--card-bg);
    border: 4px solid var(--card-bg); /* Elegant white polaroid-style border framework */
    box-shadow: 0 6px 15px rgba(15, 23, 42, 0.06);
    transition: transform 0.25s ease;
}

.gallery-container img:hover {
    transform: scale(1.03); /* Tiny responsive swell animation when hovering */
    box-shadow: 0 10px 22px rgba(15, 23, 42, 0.12);
}